explain xkcd - User contributions [en]

2120: Brain Hemispheres

2019-03-08T07:34:59Z

172.68.110.46:

{{comic
| number = 2120
| date = March 6, 2019
| title = Brain Hemispheres
| image = brain_hemispheres.png
| titletext = Neurologically speaking, the LEFT hand is actually the one at the end of the RIGHT arm.
}}

==Explanation==
{{incomplete|Created by an AUTONOMOUS LEG and a CHICKEN. The links "these", "two", and "left" are nonsense for a reader, please explain the content and provide a link-text revealing the title ot something similar of the linked article. Please mention here why this explanation isn't complete. Do NOT delete this tag too soon.}}

As a general rule, each cerebral hemisphere (half of the brain) innervates (feeds/supplies/controls) the contralateral (opposite side) portion of the body. So things on the left half of the body are controlled by the right side of the brain and vice-versa. As previously noted however, this is simply a rough approximation. As all things biology, God (or evolution, or pick your deity/creator of choice) enjoys unnecessary convolution [citation needed]; as always to most biology "rules" there are exceptions.

A notable exception are the cranial nerves; some do not decussate (cross over) as would be predicted from the rule above and directly innervate the ipsilateral (same side) side (eg abducens CN6). And of course, many cranial nerves innervate both ipsilateral and contralateral sides. This phenomenon is often seen, when everything is working properly, in things like the pupillary reflex (when you shine a bright light in one eye, both eyes' pupils constrict)

While the motor and sensation aspects of nerve innervation have been relatively well-established from studies, experiments, and dissections, (mostly through knockout(what happens to function if I damage/remove this part of the brain?) or stimulation studies) there is probably always going to be an exception, as you might imagine. Any number of factors may cause deviation from the normal physiology: trauma, disease, congenital birth defects, brain plasticity, etc.

With less concrete aspects of human brain function, such as logic, emotion, language processing, and creativity, establishing which brain hemisphere has control is obviously more complicated. Because a lot of these are higher order functions (these are things you tend to learn, develop, and obtain as you grow into an adult from a neonate), establishing which hemisphere has control of which function are obviously more complicated. Due again to brain plasticity or other factors, different developing brains may grow to wire control of these functions differently. So while studies have established which hemisphere is more likely to be involved with which function (eg left with language processing), again mostly through knockout studies, these generalizations are not necessarily true for every individual.

Randall spoofs these by suggesting that the right brain instead controls the upper torso, while the left brain still controls the right side. The product of this partitioning in two dimensions gives four areas of the human body (upper left, upper right, lower left, lower right) and would eventually suggest that your left leg moves independently of your brain. To explain the areas of the body controlled by both halves of the brain, Randall declares those sections "disputed," echoing a note added on maps that must display a border which is part of a {{w|territorial dispute}}. This suggests that the halves of your brain fight for control of the region, and is also described similarly to two countries disputing territory. Alternatively, he states there would be cooperative shared control (= {{w|Dual control}}) like in an airplane, where the pilot and the copilot both can control the plane with their respective yoke or stick at any time. His (fun) theory would explain, why most people are more skilled with their hands than their feet and with their right side than their left.

==Transcript==
{{incomplete transcript|Do NOT delete this tag too soon.}}
:[Cueball is shown with the right half of his brain (on the viewer's left) colored in orange and the left half (on the viewer's right) in iris blue. An iris blue box is overlaid over the right half of the body (on the viewer's left), and an orange box is overlaid over the top half. The boxes are overlapping in a greenish color on the upper right quarter of the body (on the viewer's left).]
:'''Neuroscience Fact:'''
:[An arrow pointing to the iris blue rectangle on top with the text above:]
:The ''left'' half of the brain actually controls the ''right'' half of the body...
:[An arrow pointing to the orange rectangle at the right, the text reads:]
:...while the ''right'' half of the brain actually controls the ''top'' half of the body.
:[An arrow pointing to the overlapping area (the top left body from the viewers perspective) with the text below:]
:Disputed/dual control
:[An arrow pointing to Cueball's left leg area (on the viewer's right), not highlighted by any color, and the text is:]
:This leg is fully autonomous

{{comic discussion}}

[[Category:Comics with color]]
[[Category:Comics featuring Cueball]]
[[Category:Biology]]

2120: Brain Hemispheres

2019-03-08T07:34:05Z

172.68.110.46:

{{comic
| number = 2120
| date = March 6, 2019
| title = Brain Hemispheres
| image = brain_hemispheres.png
| titletext = Neurologically speaking, the LEFT hand is actually the one at the end of the RIGHT arm.
}}

==Explanation==
{{incomplete|Created by an AUTONOMOUS LEG and a CHICKEN. The links "these", "two", and "left" are nonsense for a reader, please explain the content and provide a link-text revealing the title ot something similar of the linked article. Please mention here why this explanation isn't complete. Do NOT delete this tag too soon.}}

As a general rule, each cerebral hemisphere (half of the brain) innervates (feeds/supplies/controls) the contralateral (opposite side) portion of the body. So things on the left half of the body are controlled by the right side of the brain and vice-versa. As previously noted however, this is simply a rough approximation. As all things biology, God (or evolution, or pick your deity/creator of choice) enjoys unnecessary convolution [citation needed]; as always to most biology "rules" there are exceptions.

A notable exception are the cranial nerves; some do not decussate (cross over) as would be predicted from the rule above and directly innervate the ipsilateral (same side) side (eg abducens CN6). And of course, many cranial nerves innervate both ipsilateral and contralateral sides. This phenomenon is often seen, when everything is working properly, in things like the pupillary reflex (when you shine a bright light in one eye, both eyes' pupils constrict)

While the motor and sensation aspects of nerve innervation have been relatively well-established from studies, experiments, and dissections, (mostly through knockout(what happens to function if I damage/remove this part of the brain?) or stimulation studies) there is probably always going to be an exception, as you might imagine. Any number of factors may cause deviation from the normal physiology: trauma, disease, congenital birth defects, brain plasticity, etc.

With less concrete aspects of human brain function, such as logic, emotion, language processing, and creativity, establishing which brain hemisphere has control is obviously more complicated. Because a lot of these are higher order functions (these are things you tend to learn, develop, and obtain as you grow into an adult from a neonate), establishing which hemisphere has control of which function are obviously more complicated. Due again to brain plasticity or other factors, different developing brains may grow to wire control of these functions differently. So while studies have established which hemisphere is more likely to be involved with which function (eg left with language processing), again mostly through knockout studies, these generalizations are not necessarily true for every individual.

Randall spoofs these by suggesting that the right brain instead controls the upper torso, while the left brain still controls the right side. The product of this partitioning in two dimensions gives four areas of the human body (upper left, upper right, lower left, lower right) and would eventually suggest that your left leg moves independently of your brain. To explain the areas of the body controlled by both halves of the brain, Randall declares those sections "disputed," echoing a note added on maps that must display a border which is part of a {{w|territorial dispute}}. This suggests that the halves of your brain fight for control of the region, and is also described similarly to two countries disputing territory. Alternatively, he states there would be cooperative shared control (= {{w|Dual control}}) like in an airplane, where the pilot and the copilot both can control the plane with their yoke or stick. His (fun) theory would explain, why most people are more skilled with their hands than their feet and with their right side than their left.

==Transcript==
{{incomplete transcript|Do NOT delete this tag too soon.}}
:[Cueball is shown with the right half of his brain (on the viewer's left) colored in orange and the left half (on the viewer's right) in iris blue. An iris blue box is overlaid over the right half of the body (on the viewer's left), and an orange box is overlaid over the top half. The boxes are overlapping in a greenish color on the upper right quarter of the body (on the viewer's left).]
:'''Neuroscience Fact:'''
:[An arrow pointing to the iris blue rectangle on top with the text above:]
:The ''left'' half of the brain actually controls the ''right'' half of the body...
:[An arrow pointing to the orange rectangle at the right, the text reads:]
:...while the ''right'' half of the brain actually controls the ''top'' half of the body.
:[An arrow pointing to the overlapping area (the top left body from the viewers perspective) with the text below:]
:Disputed/dual control
:[An arrow pointing to Cueball's left leg area (on the viewer's right), not highlighted by any color, and the text is:]
:This leg is fully autonomous

{{comic discussion}}

[[Category:Comics with color]]
[[Category:Comics featuring Cueball]]
[[Category:Biology]]

Talk:2120: Brain Hemispheres

2019-03-07T08:41:48Z

172.68.110.46:

https://en.wikipedia.org/wiki/Cerebral_hemisphere#Hemisphere_lateralization
If the left side controls the top half of the body, wouldn't that mean it also controls the right half? [[Special:Contributions/108.162.241.248|108.162.241.248]] 20:04, 6 March 2019 (UTC)
: It is uncontroversial that many senses and motoric functions are swapped between the right and left side. The anatomy of the nerve swaps can also be shown. But it is still under discussion, why evolution led to this swap (source: [https://en.wikipedia.org/wiki/Contralateral_brain Contralateral brain] and the even better organized German version [https://de.wikipedia.org/wiki/Kontralateralit%C3%A4t_des_Vorderhirns Kontralateralität des Vorderhirns]) Sebastian --[[Special:Contributions/172.68.110.46|172.68.110.46]] 08:41, 7 March 2019 (UTC)

I don't think the sentence "all 3 claims are false" is accurate. I think the claim that the right side of your brain controls the left side of your body is accurate. It says so on the Wikipedia article mentioned and in several other sources. What the Wikipedia article disputes is whether or not "higher-level" functions are partitioned to one side of the brain. [[Special:Contributions/172.69.42.64|172.69.42.64]] 20:29, 6 March 2019 (UTC) Harrison
: With regard to the retina, the right half of the brain processes what the right half of each retina receives, and the left half processes what the left half of each retina receives (see e.g. [https://nba.uth.tmc.edu/neuroscience/m/s2/chapter15.html optic nerve]), but because our retina is behind the focal point of our lens so all the lightbeams cross and images hit the back of the eyeball upside-down and backwards, that means the halves of our brain process the opposite halves of what we see. But it's the same side of our body! I stopped learning neuroscience after we got to the optic nerve ;p [[Special:Contributions/108.162.221.95|108.162.221.95]] 21:48, 6 March 2019 (UTC)

:I think the "right side of your brain controls the left side of your body" is NOT accurate, it's just closer to truth than the reverse. Some parts of perception and motor control are divided that way, but unless you have corpus callosotomy the high-level control is centralized and/or distributed regardless the side. Would be hard to synchronize both hands if not. -- [[User:Hkmaly|Hkmaly]] ([[User talk:Hkmaly|talk]]) 02:05, 7 March 2019 (UTC)

Having survived an ischemic stroke on the left side of my brain, which temporarily paralyzed the right side of my body, this comic speaks to me like none other.

Talk:2120: Brain Hemispheres

2019-03-07T08:41:14Z

172.68.110.46:

https://en.wikipedia.org/wiki/Cerebral_hemisphere#Hemisphere_lateralization
If the left side controls the top half of the body, wouldn't that mean it also controls the right half? [[Special:Contributions/108.162.241.248|108.162.241.248]] 20:04, 6 March 2019 (UTC)
: It is uncontroversial that many senses and motoric functions are swapped between the right and left side. The anatomy of the nerve swaps can also be shown. But it is still under discussion, why evolution led to this swap [https://en.wikipedia.org/wiki/Contralateral_brain Contralateral brain] and the even better organized German version [https://de.wikipedia.org/wiki/Kontralateralit%C3%A4t_des_Vorderhirns Kontralateralität des Vorderhirns] Sebastian --[[Special:Contributions/172.68.110.46|172.68.110.46]] 08:41, 7 March 2019 (UTC)

I don't think the sentence "all 3 claims are false" is accurate. I think the claim that the right side of your brain controls the left side of your body is accurate. It says so on the Wikipedia article mentioned and in several other sources. What the Wikipedia article disputes is whether or not "higher-level" functions are partitioned to one side of the brain. [[Special:Contributions/172.69.42.64|172.69.42.64]] 20:29, 6 March 2019 (UTC) Harrison
: With regard to the retina, the right half of the brain processes what the right half of each retina receives, and the left half processes what the left half of each retina receives (see e.g. [https://nba.uth.tmc.edu/neuroscience/m/s2/chapter15.html optic nerve]), but because our retina is behind the focal point of our lens so all the lightbeams cross and images hit the back of the eyeball upside-down and backwards, that means the halves of our brain process the opposite halves of what we see. But it's the same side of our body! I stopped learning neuroscience after we got to the optic nerve ;p [[Special:Contributions/108.162.221.95|108.162.221.95]] 21:48, 6 March 2019 (UTC)

:I think the "right side of your brain controls the left side of your body" is NOT accurate, it's just closer to truth than the reverse. Some parts of perception and motor control are divided that way, but unless you have corpus callosotomy the high-level control is centralized and/or distributed regardless the side. Would be hard to synchronize both hands if not. -- [[User:Hkmaly|Hkmaly]] ([[User talk:Hkmaly|talk]]) 02:05, 7 March 2019 (UTC)

Having survived an ischemic stroke on the left side of my brain, which temporarily paralyzed the right side of my body, this comic speaks to me like none other.

2100: Models of the Atom

2019-01-30T09:00:49Z

172.68.110.46:

{{comic
| number = 2100
| date = January 18, 2019
| title = Models of the Atom
| image = models_of_the_atom.png
| titletext = J.J. Thompson won a Nobel Prize for his work in electricity in gases, but was unfairly passed over for his "An atom is plum pudding, and plum pudding is MADE of atoms! Duuuuude." theory.
}}

==Explanation==
{{incomplete|Created by a COMPLAINING EQUATION. Please mention here why this explanation isn't complete. Do NOT delete this tag too soon.}}

This comic humorously describes the changing view of what an {{w|atom}} is. This has happened so much it seems that we never really knew what we are looking at, and there have been many competing theories aside from the mainstream ones we are taught in school. He lists major depictions in the history of our understanding of an atom, and adds a few humorous ones in to poke fun at how diverse, contentious, and in retrospect often foolhardy, this history has been.

;Small hard ball model
The first model shown, in 1810, is said to be a "small hard ball model." Around this time, {{w|John Dalton}} published his textbook ''A New System of Chemical Philosophy'' which linked existing ideas of atomic theory and chemical reactivity to produce a combined {{w|Law of multiple proportions}} which proposed that each chemical element is comprised of a single unique type of atom, and introduced the concept of {{w|Molecular mass|molecular weight}}. Dalton's theories form the basis of what is known today as {{w|stoichiometry}}, which underpins chemical reactivity. As atoms were considered at this time to be the smallest possible division of matter the scientific community thought of them as "hard round balls" of different sizes; thus the name described here. The "small hard ball" model is still commonly used when teaching and discussing chemical molecules which do not require the level of detail provided by more advanced models, with atoms represented as small, hard, round balls connected by sticks representing chemical bonds.

;Plum pudding model
In the late 19th and early 20th centuries, the study of these "atom" things faced a crisis: where would the newly discovered "{{w|electron}}s" go? In 1904, physicist {{w|J. J. Thomson}}, who discovered electrons, had an idea: maybe the electrons were small point charges moving around in a big mass of positive charge. This was the "{{w|plum pudding model}}", the second model on the comic, called this because people imagined the positively charged mass as a "{{w|Christmas pudding|plum pudding}}". (The title text references Thomson as well, along with the humorous observation that plum puddings themselves are made of atoms.) The problem with this approach is that same charges generally repel, resulting in the more mobile or unbalanced charges forming a surface shell around the others, attempting to escape, rather than being content to being randomly distributed among them.

;Tiny bird model
There were many competing ideas in the formative years of what-are-atoms-made-of-ology, [[Randall]] makes up a 1907 "tiny bird model."

;Rutherford model
Ultimately, the tentative winner in the battle was the model of Thomson's student {{w|Ernest Rutherford}}, who discovered from electrostatic scattering experiments that the positive charge seemed to be concentrated in the center of the atom, and proposed his {{w|Rutherford model}}, or "planetary model", in 1911, where electrons orbit a very concentrated positive charge. This model has often been compared to the orbit of the planets around the sun, with the electrostatic attraction of the electrons and protons shaping the orbits, rather than gravity. This is the fourth model in the comic.

;Bohr model
The Rutherford model could not explain the discrete spectral lines in absorption and emission spectra. It also did not explain why electrons did not spiral in to the nucleus. {{w|Niels Bohr}} patched the model up by proposing that electrons could only exist in distinct "energy levels" at discrete distances from the nucleus. The 1913 "{{w|Bohr model}}", the fifth model shown here, was part of beginning quantum mechanics. Physics behaves differently at the small scale of atoms than the large scales we are more familiar with.

;Nunchuck model
Randall facetiously suggests a "{{w|Nunchaku|nunchuck}} model", the sixth model shown, of a packet of protons swinging a packet of electrons around. One can imagine a handle filled with electrons bonded by the strong nuclear force to a chain made of neutrons, bonded again by the strong nuclear force to a handle made of protons. The heavier protonic handle acts loosely as an orbital center as the electron-filled opposite handle swings wildly around it, attempting to resolve its electrostatic attraction within the restraints of its chain.

;Chadwick model
The next refinement was in the structure of the nucleus. Note that at this time, nobody thought of splitting up the nucleus into {{w|proton}}s and {{w|neutron}}s. But pretty soon people noticed that protons and neutrons existed; {{w|James Chadwick}}, who discovered the neutron, figured that the atom had a nucleus of neutrons and protons, along with a bunch of electrons orbiting around it in a Bohrish manner. This is what the layman today often thinks of as an atom, and is the seventh model shown here.

;538 Model
The eighth model shown is a made up "538 model," in 2008. {{w|FiveThirtyEight|538}} is a statistical analysis website that gained fame in 2008 for predicting every race but 2 correctly in the {{w|2008 United States presidential election|US presidential election}} and predicting every state and Obama's win in the 2012 election. Unlike most other media and polling institutes it saw a rather high probability of 29% for Trump to win the 2016 election by summing up the uncertainties in all the battle states. It has since been known for making mathematical models for everything; the model jokingly suggests that 538 has modeled and presumably made predictions about the atom. The {{w|pie chart}} shows the statistical composition of neutrons, protons and electrons, 38%, 31%, and 31% respectively. This could either be the average of a massive body with several isotopes or represent gallium-69, the most abundant {{w|Isotopes of gallium|isotope of gallium}}, with 31 protons, 31 electrons and 38 neutrons. FiveThirtyEight has previously been mentioned in several xkcd comics, including in [[477: Typewriter]], [[500: Election]], [[635: Locke and Demosthenes]], [[1130: Poll Watching]], [[1779: 2017]], and [[2002: LeBron James and Stephen Curry]]. It's appropriate to list the 538 model as a precursor to the quantum model, as it is a step towards considering the likelihood of different quantities of subatomic particles to be in different volumes of space, rather than considering them as strictly kinematic particles. The comic moves this development into 2008 in support of this joke, when it was actually made much earlier.

;Quantum model
But is the Chadwick model what scientists endorse today? No!
{{w|Maxwell's equations|The theory of electromagnetism}} says that accelerated charges, like the electrons circling, would lose energy emitted as electromagnetic waves and would quickly orbit into the nucleus. Bohr only postulated that this would not happen, but his model could not explain why. Another problem{{Citation needed}} is that atoms, even the hydrogen atom are not flat - which they would be, if a single electron orbited in a circular or elliptical trajectory (the circular motion of charge results in a magnetic moment; Otto Stern and Walter Gerlach {{w|Stern–Gerlach experiment|showed}} that independent from the direction of the measurement the angular momentum - for certain elements - always has the maximum positive or negative value, i.e. not only the radius, but also the angular momentum is quantized - and never zero. You cannot 'look at' the atom from above and 'see' the orbital circle. It always 'seems', as if you 'looked' from the side and would measure the full magnetic dipole. Stern and Gerlach actually saw the spin of an electron of the silver atom instead of the angular momentum, which is according to quantum mechanics 0).
Today (i.e. actually since 1926, 29 years after the discovery of the electron) physicists subscribe to a quantum model, which is the ninth model shown here. Instead of electrons with definite location and momentum (~speed), the parts of the atom are described by probability fields of possible locations and momentums. The changes in momentum probability normally cancel each other out, so there is no electromagnetic radiation. This is very abstract, and in the last model, the model is postulated to get so abstract that it is just a "small hard ball surrounded by math" model, the last model shown. This then is remarkably similar to the model we started out from, the "small hard ball model" (without the math).

;“Small hard ball surrounded by math” model
The picture for the "small ball surrounded by math" depicts a circle with several numbers around it. While the numbers seem to symbolize the "surrounding math" in a general sense, some of them suggest constants used in actual mathematical equations or other numbers related to the quantum model. The shapes and densities of the atomic orbitals are calculated with the {{w|Schrödinger equation}}, which is complex and difficult to solve. Or with string theory, which does not make it easier. For this reason atoms are generally precisely considered in only very simple simulations, and the details of interactions of many atoms at large scales that form our daily lives are incredibly hard to precisely understand and predict on an atomic level. It comes down to "these roundish things we call atoms are moving around in these approximate ways obeying this complex equation with too many numbers involved in most situations to accurately model, so let's use a different, empirically derived formula that describes the behavior of the system in general."

{| class="wikitable"
|-
! Number !! Explanation
|-
| 18 || Maximum number of electrons in the third (M) {{w|electron shell}}
|-
| 0.1 || 1/10th, a simple decimal. Could be the atomic radius in nm of elements like phosphorus, sulfur, and chlorine. Also part of the definition of the {{w|Decibel#Field_quantities_and_root-power_quantities|Decibel}} which is sometimes used when measuring fields
|-
| π || The {{w|Pi|number pi}} ratio of circumference of a circle to half its diameter. Pi is present in many physics equations, often as its double value (2π); also in the definition of the {{w|Planck_constant#Value|reduced Planck constant ħ (h bar)}} present in quantum-mechanical equations.
|-
| 173 || Could be the mass of the top quark in GeV/c². Or it could be the atomic number from which point {{w|Extended periodic table|supercritical atoms}} (the innermost electron shells of those supercritical atoms have such high binding energies that they {{w|Pair production|create electron-positron pairs from the vaccum}} and thus cannot be fully ionized) start. This atomic number can be calculated by a mathematical term and does not fit to a typical fundamental physical theory. Alternatively, a typo, and it should be 137, referring to the fine structure constant which value is approximately 1/137. As an interesting aside, the start of the supercritical atoms would be exactly the fine-structure-constant 137, if the nucleus is assumed to have zero size, and in the Bohr model of such an atom the speed of the innermost electron would reach light speed.
|-
| √2 || An irrational constant, the square root of two, which comes up frequently
|-
| 4i || A simple complex number; i is the principal square root of -1, 4i is the principal square root of -16
|}

==Transcript==
{{incomplete transcript|Do NOT delete this tag too soon.}}
:[One large panel with a caption centered on top and ten small drawings in two rows. Each drawing has a description below it.]

:'''Models of the Atom'''
:over time

:[A somewhat imperfectly drawn circle.]
:1810 Small hard ball model

:[A rounded-corners trapezoid inside which there are four small plus signs and four small circles with minus signs inside them.]
:1904 Plum pudding model

:[A bigger circle, with four birds on the surface and music notes above.]
:1907 Tiny bird model

:[A small circle with dots circling around it, drawn with paths.]
:1911 Rutherford model

:[A circle with a plus sign with three circles around it, each with a dot.]
:1913 Bohr model

:[A nunchuck swinging, with the left stick filled with circles with plus signs and the right stick filled with circles with minus signs.]
:1928 Nunchuck model

:[A nucleus with three circles around it, each with a dot.]
:1932 Chadwick model

:[A pie chart, where a part of it has a circle, a part of it has a circle with a minus sign and a part of it has a circle with a plus sign.]
:2008 538 model

:[A small circle with clover-like orbitals around it and surrounded by two outer partly dashed circles.]
:Today Quantum model

:[A circle surrounded with numbers.]
:Numbers: 18, 0.1, π, 173, √2, 4i
:Future "Small hard ball surrounded by math" model

{{comic discussion}}

[[Category:Charts]]
[[Category:Comics featuring real people]] 
[[Category:Physics]]
[[Category:Animals]]

2100: Models of the Atom

2019-01-30T08:55:36Z

172.68.110.46:

{{comic
| number = 2100
| date = January 18, 2019
| title = Models of the Atom
| image = models_of_the_atom.png
| titletext = J.J. Thompson won a Nobel Prize for his work in electricity in gases, but was unfairly passed over for his "An atom is plum pudding, and plum pudding is MADE of atoms! Duuuuude." theory.
}}

==Explanation==
{{incomplete|Created by a COMPLAINING EQUATION. Please mention here why this explanation isn't complete. Do NOT delete this tag too soon.}}

This comic humorously describes the changing view of what an {{w|atom}} is. This has happened so much it seems that we never really knew what we are looking at, and there have been many competing theories aside from the mainstream ones we are taught in school. He lists major depictions in the history of our understanding of an atom, and adds a few humorous ones in to poke fun at how diverse, contentious, and in retrospect often foolhardy, this history has been.

;Small hard ball model
The first model shown, in 1810, is said to be a "small hard ball model." Around this time, {{w|John Dalton}} published his textbook ''A New System of Chemical Philosophy'' which linked existing ideas of atomic theory and chemical reactivity to produce a combined {{w|Law of multiple proportions}} which proposed that each chemical element is comprised of a single unique type of atom, and introduced the concept of {{w|Molecular mass|molecular weight}}. Dalton's theories form the basis of what is known today as {{w|stoichiometry}}, which underpins chemical reactivity. As atoms were considered at this time to be the smallest possible division of matter the scientific community thought of them as "hard round balls" of different sizes; thus the name described here. The "small hard ball" model is still commonly used when teaching and discussing chemical molecules which do not require the level of detail provided by more advanced models, with atoms represented as small, hard, round balls connected by sticks representing chemical bonds.

;Plum pudding model
In the late 19th and early 20th centuries, the study of these "atom" things faced a crisis: where would the newly discovered "{{w|electron}}s" go? In 1904, physicist {{w|J. J. Thomson}}, who discovered electrons, had an idea: maybe the electrons were small point charges moving around in a big mass of positive charge. This was the "{{w|plum pudding model}}", the second model on the comic, called this because people imagined the positively charged mass as a "{{w|Christmas pudding|plum pudding}}". (The title text references Thomson as well, along with the humorous observation that plum puddings themselves are made of atoms.) The problem with this approach is that same charges generally repel, resulting in the more mobile or unbalanced charges forming a surface shell around the others, attempting to escape, rather than being content to being randomly distributed among them.

;Tiny bird model
There were many competing ideas in the formative years of what-are-atoms-made-of-ology, [[Randall]] makes up a 1907 "tiny bird model."

;Rutherford model
Ultimately, the tentative winner in the battle was the model of Thomson's student {{w|Ernest Rutherford}}, who discovered from electrostatic scattering experiments that the positive charge seemed to be concentrated in the center of the atom, and proposed his {{w|Rutherford model}}, or "planetary model", in 1911, where electrons orbit a very concentrated positive charge. This model has often been compared to the orbit of the planets around the sun, with the electrostatic attraction of the electrons and protons shaping the orbits, rather than gravity. This is the fourth model in the comic.

;Bohr model
The Rutherford model could not explain the discrete spectral lines in absorption and emission spectra. It also did not explain why electrons did not spiral in to the nucleus. {{w|Niels Bohr}} patched the model up by proposing that electrons could only exist in distinct "energy levels" at discrete distances from the nucleus. The 1913 "{{w|Bohr model}}", the fifth model shown here, was part of beginning quantum mechanics. Physics behaves differently at the small scale of atoms than the large scales we are more familiar with.

;Nunchuck model
Randall facetiously suggests a "{{w|Nunchaku|nunchuck}} model", the sixth model shown, of a packet of protons swinging a packet of electrons around. One can imagine a handle filled with electrons bonded by the strong nuclear force to a chain made of neutrons, bonded again by the strong nuclear force to a handle made of protons. The heavier protonic handle acts loosely as an orbital center as the electron-filled opposite handle swings wildly around it, attempting to resolve its electrostatic attraction within the restraints of its chain.

;Chadwick model
The next refinement was in the structure of the nucleus. Note that at this time, nobody thought of splitting up the nucleus into {{w|proton}}s and {{w|neutron}}s. But pretty soon people noticed that protons and neutrons existed; {{w|James Chadwick}}, who discovered the neutron, figured that the atom had a nucleus of neutrons and protons, along with a bunch of electrons orbiting around it in a Bohrish manner. This is what the layman today often thinks of as an atom, and is the seventh model shown here.

;538 Model
The eighth model shown is a made up "538 model," in 2008. {{w|FiveThirtyEight|538}} is a statistical analysis website that gained fame in 2008 for predicting every race but 2 correctly in the {{w|2008 United States presidential election|US presidential election}} and predicting every state and Obama's win in the 2012 election. Unlike most other media and polling institutes it saw a rather high probability of 29% for Trump to win the 2016 election by summing up the uncertainties in all the battle states. It has since been known for making mathematical models for everything; the model jokingly suggests that 538 has modeled and presumably made predictions about the atom. The {{w|pie chart}} shows the statistical composition of neutrons, protons and electrons, 38%, 31%, and 31% respectively. This could either be the average of a massive body with several isotopes or represent gallium-69, the most abundant {{w|Isotopes of gallium|isotope of gallium}}, with 31 protons, 31 electrons and 38 neutrons. FiveThirtyEight has previously been mentioned in several xkcd comics, including in [[477: Typewriter]], [[500: Election]], [[635: Locke and Demosthenes]], [[1130: Poll Watching]], [[1779: 2017]], and [[2002: LeBron James and Stephen Curry]]. It's appropriate to list the 538 model as a precursor to the quantum model, as it is a step towards considering the likelihood of different quantities of subatomic particles to be in different volumes of space, rather than considering them as strictly kinematic particles. The comic moves this development into 2008 in support of this joke, when it was actually made much earlier.

;Quantum model
But is the Chadwick model what scientists endorse today? No!
{{w|Maxwell's equations|The theory of electromagnetism}} says that accelerated charges, like the electrons circling, would lose energy emitted as electromagnetic waves and would quickly orbit into the nucleus. Bohr only postulated that this would not happen, but his model could not explain why. Another problem{{Citation needed}} is that atoms, even the hydrogen atom are not flat - which they would be, if a single electron orbited in a circular or elliptical trajectory (the circular motion of charge results in a magnetic moment; Otto Stern and Walter Gerlach {{w|Stern–Gerlach experiment|showed}} that independent from the direction of the measurement the angular momentum - for certain elements - always has the maximum positive or negative value, i.e. not only the radius, but also the angular momentum is quantized - and never zero. You cannot 'look at' the atom from above and 'see' the orbital circle. It always 'seems', as if you 'looked' from the side and would measure the full magnetic dipole. Stern and Gerlach actually saw the spin of an electron of the silver atom instead of the angular momentum, which is according to quantum mechanics 0).
Today (i.e. actually since 1926, 29 years after the discovery of the electron) physicists subscribe to a quantum model, which is the ninth model shown here. Instead of electrons with definite location and momentum (~speed), the parts of the atom are described by probability fields of possible locations and momentums. The changes in momentum probability normally cancel each other out, so there is no electromagnetic radiation. This is very abstract, and in the last model, the model is postulated to get so abstract that it is just a "small hard ball surrounded by math" model, the last model shown. This then is remarkably similar to the model we started out from, the "small hard ball model" (without the math).

;“Small hard ball surrounded by math” model
The picture for the "small ball surrounded by math" depicts a circle with several numbers around it. While the numbers seem to symbolize the "surrounding math" in a general sense, some of them suggest constants used in actual mathematical equations or other numbers related to the quantum model. The shapes and densities of the atomic orbitals are calculated with the {{w|Schrödinger equation}}, which is complex and difficult to solve. Or with string theory, which does not make it easier. For this reason atoms are generally precisely considered in only very simple simulations, and the details of interactions of many atoms at large scales that form our daily lives are incredibly hard to precisely understand and predict on an atomic level. It comes down to "these roundish things we call atoms are moving around in these approximate ways obeying this complex equation with too many numbers involved in most situations to accurately model, so let's use a different, empirically derived formula that describes the behavior of the system in general."

{| class="wikitable"
|-
! Number !! Explanation
|-
| 18 || Maximum number of electrons in the third (M) {{w|electron shell}}
|-
| 0.1 || 1/10th, a simple decimal. Could be the atomic radius in nm of elements like phosphorus, sulfur, and chlorine. Also part of the definition of the {{w|Decibel#Field_quantities_and_root-power_quantities|Decibel}} which is sometimes used when measuring fields
|-
| π || The {{w|Pi|number pi}} ratio of circumference of a circle to half its diameter. Pi is present in many physics equations, often as its double value (2π); also in the definition of the {{w|Planck_constant#Value|reduced Planck constant ħ (h bar)}} present in quantum-mechanical equations.
|-
| 173 || Could be the mass of the top quark in GeV/c². Or it could be the atomic number from which point {{w|Extended periodic table|supercritical atoms}} (the innermost electron shells of those supercritical atoms have such high binding energies that they {{w|Pair production|create electron-positron pairs from the vaccum}} and thus cannot be fully ionized) start. This atomic number can be calculated by a mathematical term and does not fit to a typical fundamental physical theory. Alternatively, a typo, and it should be 137, referring to the fine structure constant which value is approximately 1/137. As an interesting aside, the start of the supercritical atoms would be exactly the fine-structure-constant 137, if the nucleus is assumed to have zero size, and in the Bohr model of such an atom the speed of the innermost electron would reach light speed.
|-
| √2 || An irrational constant, the square root of two, which comes up frequently
|-
| 4i || A simple complex number; i is considered the square root of -1 (4i is the square root of -16)
|}

==Transcript==
{{incomplete transcript|Do NOT delete this tag too soon.}}
:[One large panel with a caption centered on top and ten small drawings in two rows. Each drawing has a description below it.]

:'''Models of the Atom'''
:over time

:[A somewhat imperfectly drawn circle.]
:1810 Small hard ball model

:[A rounded-corners trapezoid inside which there are four small plus signs and four small circles with minus signs inside them.]
:1904 Plum pudding model

:[A bigger circle, with four birds on the surface and music notes above.]
:1907 Tiny bird model

:[A small circle with dots circling around it, drawn with paths.]
:1911 Rutherford model

:[A circle with a plus sign with three circles around it, each with a dot.]
:1913 Bohr model

:[A nunchuck swinging, with the left stick filled with circles with plus signs and the right stick filled with circles with minus signs.]
:1928 Nunchuck model

:[A nucleus with three circles around it, each with a dot.]
:1932 Chadwick model

:[A pie chart, where a part of it has a circle, a part of it has a circle with a minus sign and a part of it has a circle with a plus sign.]
:2008 538 model

:[A small circle with clover-like orbitals around it and surrounded by two outer partly dashed circles.]
:Today Quantum model

:[A circle surrounded with numbers.]
:Numbers: 18, 0.1, π, 173, √2, 4i
:Future "Small hard ball surrounded by math" model

{{comic discussion}}

[[Category:Charts]]
[[Category:Comics featuring real people]] 
[[Category:Physics]]
[[Category:Animals]]

2100: Models of the Atom

2019-01-30T08:54:07Z

172.68.110.46:

{{comic
| number = 2100
| date = January 18, 2019
| title = Models of the Atom
| image = models_of_the_atom.png
| titletext = J.J. Thompson won a Nobel Prize for his work in electricity in gases, but was unfairly passed over for his "An atom is plum pudding, and plum pudding is MADE of atoms! Duuuuude." theory.
}}

==Explanation==
{{incomplete|Created by a COMPLAINING EQUATION. Please mention here why this explanation isn't complete. Do NOT delete this tag too soon.}}

This comic humorously describes the changing view of what an {{w|atom}} is. This has happened so much it seems that we never really knew what we are looking at, and there have been many competing theories aside from the mainstream ones we are taught in school. He lists major depictions in the history of our understanding of an atom, and adds a few humorous ones in to poke fun at how diverse, contentious, and in retrospect often foolhardy, this history has been.

;Small hard ball model
The first model shown, in 1810, is said to be a "small hard ball model." Around this time, {{w|John Dalton}} published his textbook ''A New System of Chemical Philosophy'' which linked existing ideas of atomic theory and chemical reactivity to produce a combined {{w|Law of multiple proportions}} which proposed that each chemical element is comprised of a single unique type of atom, and introduced the concept of {{w|Molecular mass|molecular weight}}. Dalton's theories form the basis of what is known today as {{w|stoichiometry}}, which underpins chemical reactivity. As atoms were considered at this time to be the smallest possible division of matter the scientific community thought of them as "hard round balls" of different sizes; thus the name described here. The "small hard ball" model is still commonly used when teaching and discussing chemical molecules which do not require the level of detail provided by more advanced models, with atoms represented as small, hard, round balls connected by sticks representing chemical bonds.

;Plum pudding model
In the late 19th and early 20th centuries, the study of these "atom" things faced a crisis: where would the newly discovered "{{w|electron}}s" go? In 1904, physicist {{w|J. J. Thomson}}, who discovered electrons, had an idea: maybe the electrons were small point charges moving around in a big mass of positive charge. This was the "{{w|plum pudding model}}", the second model on the comic, called this because people imagined the positively charged mass as a "{{w|Christmas pudding|plum pudding}}". (The title text references Thomson as well, along with the humorous observation that plum puddings themselves are made of atoms.) The problem with this approach is that same charges generally repel, resulting in the more mobile or unbalanced charges forming a surface shell around the others, attempting to escape, rather than being content to being randomly distributed among them.

;Tiny bird model
There were many competing ideas in the formative years of what-are-atoms-made-of-ology, [[Randall]] makes up a 1907 "tiny bird model."

;Rutherford model
Ultimately, the tentative winner in the battle was the model of Thomson's student {{w|Ernest Rutherford}}, who discovered from electrostatic scattering experiments that the positive charge seemed to be concentrated in the center of the atom, and proposed his {{w|Rutherford model}}, or "planetary model", in 1911, where electrons orbit a very concentrated positive charge. This model has often been compared to the orbit of the planets around the sun, with the electrostatic attraction of the electrons and protons shaping the orbits, rather than gravity. This is the fourth model in the comic.

;Bohr model
The Rutherford model could not explain the discrete spectral lines in absorption and emission spectra. It also did not explain why electrons did not spiral in to the nucleus. {{w|Niels Bohr}} patched the model up by proposing that electrons could only exist in distinct "energy levels" at discrete distances from the nucleus. The 1913 "{{w|Bohr model}}", the fifth model shown here, was part of beginning quantum mechanics. Physics behaves differently at the small scale of atoms than the large scales we are more familiar with.

;Nunchuck model
Randall facetiously suggests a "{{w|Nunchaku|nunchuck}} model", the sixth model shown, of a packet of protons swinging a packet of electrons around. One can imagine a handle filled with electrons bonded by the strong nuclear force to a chain made of neutrons, bonded again by the strong nuclear force to a handle made of protons. The heavier protonic handle acts loosely as an orbital center as the electron-filled opposite handle swings wildly around it, attempting to resolve its electrostatic attraction within the restraints of its chain.

;Chadwick model
The next refinement was in the structure of the nucleus. Note that at this time, nobody thought of splitting up the nucleus into {{w|proton}}s and {{w|neutron}}s. But pretty soon people noticed that protons and neutrons existed; {{w|James Chadwick}}, who discovered the neutron, figured that the atom had a nucleus of neutrons and protons, along with a bunch of electrons orbiting around it in a Bohrish manner. This is what the layman today often thinks of as an atom, and is the seventh model shown here.

;538 Model
The eighth model shown is a made up "538 model," in 2008. {{w|FiveThirtyEight|538}} is a statistical analysis website that gained fame in 2008 for predicting every race but 2 correctly in the {{w|2008 United States presidential election|US presidential election}} and predicting every state and Obama's win in the 2012 election. Unlike most other media and polling institutes it saw a rather high probability of 29% for Trump to win the 2016 election by summing up the uncertainties in all the battle states. It has since been known for making mathematical models for everything; the model jokingly suggests that 538 has modeled and presumably made predictions about the atom. The {{w|pie chart}} shows the statistical composition of neutrons, protons and electrons, 38%, 31%, and 31% respectively. This could either be the average of a massive body with several isotopes or represent gallium-69, the most abundant {{w|Isotopes of gallium|isotope of gallium}}, with 31 protons, 31 electrons and 38 neutrons. FiveThirtyEight has previously been mentioned in several xkcd comics, including in [[477: Typewriter]], [[500: Election]], [[635: Locke and Demosthenes]], [[1130: Poll Watching]], [[1779: 2017]], and [[2002: LeBron James and Stephen Curry]]. It's appropriate to list the 538 model as a precursor to the quantum model, as it is a step towards considering the likelihood of different quantities of subatomic particles to be in different volumes of space, rather than considering them as strictly kinematic particles. The comic moves this development into 2008 in support of this joke, when it was actually made much earlier.

;Quantum model
But is the Chadwick model what scientists endorse today? No!
{{w|Maxwell's equations|The theory of electromagnetism}} says that accelerated charges, like the electrons circling, would lose energy emitted as electromagnetic waves and would quickly orbit into the nucleus. Bohr only postulated that this would not happen, but his model could not explain why. Another problem{{Citation needed}} is that atoms, even the hydrogen atom are not flat - which they would be, if a single electron orbited in a circular or elliptical trajectory (the circular motion of charge results in a magnetic moment; Otto Stern and Walter Gerlach {{w|Stern–Gerlach experiment|showed}} that independent from the direction of the measurement the angular momentum - for certain elements - always has the maximum positive or negative value, i.e. not only the radius, but also the angular momentum is quantized - and never zero. You cannot 'look at' the atom from above and 'see' the orbital circle. It always 'seems', as if you 'looked' from the side and would measure the full magnetic dipole. Stern and Gerlach actually saw the spin of an electron of the silver atom instead of the angular momentum, which is according to quantum mechanics 0).
Today (i.e. actually since 1926, 29 years after the discovery of the electron) physicists subscribe to a quantum model, which is the ninth model shown here. Instead of electrons with definite location and momentum (~speed), the parts of the atom are described by probability fields of possible locations and momentums. The changes in momentum probability normally cancel each other out, so there is no electromagnetic radiation. This is very abstract, and in the last model, the model is postulated to get so abstract that it is just a "small hard ball surrounded by math" model, the last model shown. This then is remarkably similar to the model we started out from, the "small hard ball model" (without the math).

;“Small hard ball surrounded by math” model
The picture for the "small ball surrounded by math" depicts a circle with several numbers around it. While the numbers seem to symbolize the "surrounding math" in a general sense, some of them suggest constants used in actual mathematical equations or other numbers related to the quantum model. The shapes and densities of the atomic orbitals are calculated with the {{w|Schrödinger equation}}, which is complex and difficult to solve. Or with string theory, which does not make it easier. For this reason atoms are generally precisely considered in only very simple simulations, and the details of interactions of many atoms at large scales that form our daily lives are incredibly hard to precisely understand and predict on an atomic level. It comes down to "these roundish things we call atoms are moving around in these approximate ways obeying this complex equation with too many numbers involved in most situations to accurately model, so let's use a different, empirically derived formula that describes the behavior of the system in general."

{| class="wikitable"
|-
! Number !! Explanation
|-
| 18 || Maximum number of electrons in the third (M) {{w|electron shell}}
|-
| 0.1 || 1/10th, a simple decimal. Could be the atomic radius in nm of elements like phosphorus, sulfur, and chlorine. Also part of the definition of the {{w|Decibel#Field_quantities_and_root-power_quantities|Decibel sometimes used when measuring fields}}
|-
| π || The {{w|Pi|number pi}} ratio of circumference of a circle to half its diameter. Pi is present in many physics equations, often as its double value (2π); also in the definition of the {{w|Planck_constant#Value|reduced Planck constant ħ (h bar)}} present in quantum-mechanical equations.
|-
| 173 || Could be the mass of the top quark in GeV/c². Or it could be the atomic number from which point {{w|Extended periodic table|supercritical atoms}} (the innermost electron shells of those supercritical atoms have such high binding energies that they {{w|Pair production|create electron-positron pairs from the vaccum}} and thus cannot be fully ionized) start. This atomic number can be calculated by a mathematical term and does not fit to a typical fundamental physical theory. Alternatively, a typo, and it should be 137, referring to the fine structure constant which value is approximately 1/137. As an interesting aside, the start of the supercritical atoms would be exactly the fine-structure-constant 137, if the nucleus is assumed to have zero size, and in the Bohr model of such an atom the speed of the innermost electron would reach light speed.
|-
| √2 || An irrational constant, the square root of two, which comes up frequently
|-
| 4i || A simple complex number; i is considered the square root of -1 (4i is the square root of -16)
|}

==Transcript==
{{incomplete transcript|Do NOT delete this tag too soon.}}
:[One large panel with a caption centered on top and ten small drawings in two rows. Each drawing has a description below it.]

:'''Models of the Atom'''
:over time

:[A somewhat imperfectly drawn circle.]
:1810 Small hard ball model

:[A rounded-corners trapezoid inside which there are four small plus signs and four small circles with minus signs inside them.]
:1904 Plum pudding model

:[A bigger circle, with four birds on the surface and music notes above.]
:1907 Tiny bird model

:[A small circle with dots circling around it, drawn with paths.]
:1911 Rutherford model

:[A circle with a plus sign with three circles around it, each with a dot.]
:1913 Bohr model

:[A nunchuck swinging, with the left stick filled with circles with plus signs and the right stick filled with circles with minus signs.]
:1928 Nunchuck model

:[A nucleus with three circles around it, each with a dot.]
:1932 Chadwick model

:[A pie chart, where a part of it has a circle, a part of it has a circle with a minus sign and a part of it has a circle with a plus sign.]
:2008 538 model

:[A small circle with clover-like orbitals around it and surrounded by two outer partly dashed circles.]
:Today Quantum model

:[A circle surrounded with numbers.]
:Numbers: 18, 0.1, π, 173, √2, 4i
:Future "Small hard ball surrounded by math" model

{{comic discussion}}

[[Category:Charts]]
[[Category:Comics featuring real people]] 
[[Category:Physics]]
[[Category:Animals]]

2100: Models of the Atom

2019-01-30T08:47:30Z

172.68.110.46:

{{comic
| number = 2100
| date = January 18, 2019
| title = Models of the Atom
| image = models_of_the_atom.png
| titletext = J.J. Thompson won a Nobel Prize for his work in electricity in gases, but was unfairly passed over for his "An atom is plum pudding, and plum pudding is MADE of atoms! Duuuuude." theory.
}}

==Explanation==
{{incomplete|Created by a COMPLAINING EQUATION. Please mention here why this explanation isn't complete. Do NOT delete this tag too soon.}}

This comic humorously describes the changing view of what an {{w|atom}} is. This has happened so much it seems that we never really knew what we are looking at, and there have been many competing theories aside from the mainstream ones we are taught in school. He lists major depictions in the history of our understanding of an atom, and adds a few humorous ones in to poke fun at how diverse, contentious, and in retrospect often foolhardy, this history has been.

;Small hard ball model
The first model shown, in 1810, is said to be a "small hard ball model." Around this time, {{w|John Dalton}} published his textbook ''A New System of Chemical Philosophy'' which linked existing ideas of atomic theory and chemical reactivity to produce a combined {{w|Law of multiple proportions}} which proposed that each chemical element is comprised of a single unique type of atom, and introduced the concept of {{w|Molecular mass|molecular weight}}. Dalton's theories form the basis of what is known today as {{w|stoichiometry}}, which underpins chemical reactivity. As atoms were considered at this time to be the smallest possible division of matter the scientific community thought of them as "hard round balls" of different sizes; thus the name described here. The "small hard ball" model is still commonly used when teaching and discussing chemical molecules which do not require the level of detail provided by more advanced models, with atoms represented as small, hard, round balls connected by sticks representing chemical bonds.

;Plum pudding model
In the late 19th and early 20th centuries, the study of these "atom" things faced a crisis: where would the newly discovered "{{w|electron}}s" go? In 1904, physicist {{w|J. J. Thomson}}, who discovered electrons, had an idea: maybe the electrons were small point charges moving around in a big mass of positive charge. This was the "{{w|plum pudding model}}", the second model on the comic, called this because people imagined the positively charged mass as a "{{w|Christmas pudding|plum pudding}}". (The title text references Thomson as well, along with the humorous observation that plum puddings themselves are made of atoms.) The problem with this approach is that same charges generally repel, resulting in the more mobile or unbalanced charges forming a surface shell around the others, attempting to escape, rather than being content to being randomly distributed among them.

;Tiny bird model
There were many competing ideas in the formative years of what-are-atoms-made-of-ology, [[Randall]] makes up a 1907 "tiny bird model."

;Rutherford model
Ultimately, the tentative winner in the battle was the model of Thomson's student {{w|Ernest Rutherford}}, who discovered from electrostatic scattering experiments that the positive charge seemed to be concentrated in the center of the atom, and proposed his {{w|Rutherford model}}, or "planetary model", in 1911, where electrons orbit a very concentrated positive charge. This model has often been compared to the orbit of the planets around the sun, with the electrostatic attraction of the electrons and protons shaping the orbits, rather than gravity. This is the fourth model in the comic.

;Bohr model
The Rutherford model could not explain the discrete spectral lines in absorption and emission spectra. It also did not explain why electrons did not spiral in to the nucleus. {{w|Niels Bohr}} patched the model up by proposing that electrons could only exist in distinct "energy levels" at discrete distances from the nucleus. The 1913 "{{w|Bohr model}}", the fifth model shown here, was part of beginning quantum mechanics. Physics behaves differently at the small scale of atoms than the large scales we are more familiar with.

;Nunchuck model
Randall facetiously suggests a "{{w|Nunchaku|nunchuck}} model", the sixth model shown, of a packet of protons swinging a packet of electrons around. One can imagine a handle filled with electrons bonded by the strong nuclear force to a chain made of neutrons, bonded again by the strong nuclear force to a handle made of protons. The heavier protonic handle acts loosely as an orbital center as the electron-filled opposite handle swings wildly around it, attempting to resolve its electrostatic attraction within the restraints of its chain.

;Chadwick model
The next refinement was in the structure of the nucleus. Note that at this time, nobody thought of splitting up the nucleus into {{w|proton}}s and {{w|neutron}}s. But pretty soon people noticed that protons and neutrons existed; {{w|James Chadwick}}, who discovered the neutron, figured that the atom had a nucleus of neutrons and protons, along with a bunch of electrons orbiting around it in a Bohrish manner. This is what the layman today often thinks of as an atom, and is the seventh model shown here.

;538 Model
The eighth model shown is a made up "538 model," in 2008. {{w|FiveThirtyEight|538}} is a statistical analysis website that gained fame in 2008 for predicting every race but 2 correctly in the {{w|2008 United States presidential election|US presidential election}} and predicting every state and Obama's win in the 2012 election. Unlike most other media and polling institutes it saw a rather high probability of 29% for Trump to win the 2016 election by summing up the uncertainties in all the battle states. It has since been known for making mathematical models for everything; the model jokingly suggests that 538 has modeled and presumably made predictions about the atom. The {{w|pie chart}} shows the statistical composition of neutrons, protons and electrons, 38%, 31%, and 31% respectively. This could either be the average of a massive body with several isotopes or represent gallium-69, the most abundant {{w|Isotopes of gallium|isotope of gallium}}, with 31 protons, 31 electrons and 38 neutrons. FiveThirtyEight has previously been mentioned in several xkcd comics, including in [[477: Typewriter]], [[500: Election]], [[635: Locke and Demosthenes]], [[1130: Poll Watching]], [[1779: 2017]], and [[2002: LeBron James and Stephen Curry]]. It's appropriate to list the 538 model as a precursor to the quantum model, as it is a step towards considering the likelihood of different quantities of subatomic particles to be in different volumes of space, rather than considering them as strictly kinematic particles. The comic moves this development into 2008 in support of this joke, when it was actually made much earlier.

;Quantum model
But is the Chadwick model what scientists endorse today? No!
{{w|Maxwell's equations|The theory of electromagnetism}} says that accelerated charges, like the electrons circling, would lose energy emitted as electromagnetic waves and would quickly orbit into the nucleus. Bohr only postulated that this would not happen, but his model could not explain why. Another problem{{Citation needed}} is that atoms, even the hydrogen atom are not flat - which they would be, if a single electron orbited in a circular or elliptical trajectory (the circular motion of charge results in a magnetic moment; Otto Stern and Walter Gerlach {{w|Stern–Gerlach experiment|showed}} that independent from the direction of the measurement the angular momentum - for certain elements - always has the maximum positive or negative value, i.e. not only the radius, but also the angular momentum is quantized - and never zero. You cannot 'look at' the atom from above and 'see' the orbital circle. It always 'seems', as if you 'looked' from the side and would measure the full magnetic dipole. Stern and Gerlach actually saw the spin of an electron of the silver atom instead of the angular momentum, which is according to quantum mechanics 0).
Today (i.e. actually since 1926, 29 years after the discovery of the electron) physicists subscribe to a quantum model, which is the ninth model shown here. Instead of electrons with definite location and momentum (~speed), the parts of the atom are described by probability fields of possible locations and momentums. The changes in momentum probability normally cancel each other out, so there is no electromagnetic radiation. This is very abstract, and in the last model, the model is postulated to get so abstract that it is just a "small hard ball surrounded by math" model, the last model shown. This then is remarkably similar to the model we started out from, the "small hard ball model" (without the math).

;“Small hard ball surrounded by math” model
The picture for the "small ball surrounded by math" depicts a circle with several numbers around it. While the numbers seem to symbolize the "surrounding math" in a general sense, some of them suggest constants used in actual mathematical equations or other numbers related to the quantum model. The shapes and densities of the atomic orbitals are calculated with the {{w|Schrödinger equation}}, which is complex and difficult to solve. Or with string theory, which does not make it easier. For this reason atoms are generally precisely considered in only very simple simulations, and the details of interactions of many atoms at large scales that form our daily lives are incredibly hard to precisely understand and predict on an atomic level. It comes down to "these roundish things we call atoms are moving around in these approximate ways obeying this complex equation with too many numbers involved in most situations to accurately model, so let's use a different, empirically derived formula that describes the behavior of the system in general."

{| class="wikitable"
|-
! Number !! Explanation
|-
| 18 || Maximum number of electrons in the third (M) {{w|electron shell}}
|-
| 0.1 || 1/10th, a simple decimal
|-
| π || The {{w|Pi|number pi}} ratio of circumference of a circle to half its diameter. Pi is present in many physics equations, often as its double value (2π); also in the definition of the {{w|Planck_constant#Value|reduced Planck constant ħ (h bar)}} present in quantum-mechanical equations.
|-
| 173 || Could be the mass of the top quark in GeV/c². Or it could be the atomic number from which point {{w|Extended periodic table|supercritical atoms}} (the innermost electron shells of those supercritical atoms have such high binding energies that they {{w|Pair production|create electron-positron pairs from the vaccum}} and thus cannot be fully ionized) start. This atomic number can be calculated by a mathematical term and does not fit to a typical fundamental physical theory. Alternatively, a typo, and it should be 137, referring to the fine structure constant which value is approximately 1/137. As an interesting aside, the start of the supercritical atoms would be exactly the fine-structure-constant 137, if the nucleus is assumed to have zero size, and in the Bohr model of such an atom the speed of the innermost electron would reach light speed.
|-
| √2 || An irrational constant, the square root of two, which comes up frequently
|-
| 4i || A simple complex number; i is considered the square root of -1 (4i is the square root of -16)
|}

==Transcript==
{{incomplete transcript|Do NOT delete this tag too soon.}}
:[One large panel with a caption centered on top and ten small drawings in two rows. Each drawing has a description below it.]

:'''Models of the Atom'''
:over time

:[A somewhat imperfectly drawn circle.]
:1810 Small hard ball model

:[A rounded-corners trapezoid inside which there are four small plus signs and four small circles with minus signs inside them.]
:1904 Plum pudding model

:[A bigger circle, with four birds on the surface and music notes above.]
:1907 Tiny bird model

:[A small circle with dots circling around it, drawn with paths.]
:1911 Rutherford model

:[A circle with a plus sign with three circles around it, each with a dot.]
:1913 Bohr model

:[A nunchuck swinging, with the left stick filled with circles with plus signs and the right stick filled with circles with minus signs.]
:1928 Nunchuck model

:[A nucleus with three circles around it, each with a dot.]
:1932 Chadwick model

:[A pie chart, where a part of it has a circle, a part of it has a circle with a minus sign and a part of it has a circle with a plus sign.]
:2008 538 model

:[A small circle with clover-like orbitals around it and surrounded by two outer partly dashed circles.]
:Today Quantum model

:[A circle surrounded with numbers.]
:Numbers: 18, 0.1, π, 173, √2, 4i
:Future "Small hard ball surrounded by math" model

{{comic discussion}}

[[Category:Charts]]
[[Category:Comics featuring real people]] 
[[Category:Physics]]
[[Category:Animals]]

2100: Models of the Atom

2019-01-30T08:45:32Z

172.68.110.46:

{{comic
| number = 2100
| date = January 18, 2019
| title = Models of the Atom
| image = models_of_the_atom.png
| titletext = J.J. Thompson won a Nobel Prize for his work in electricity in gases, but was unfairly passed over for his "An atom is plum pudding, and plum pudding is MADE of atoms! Duuuuude." theory.
}}

==Explanation==
{{incomplete|Created by a COMPLAINING EQUATION. Please mention here why this explanation isn't complete. Do NOT delete this tag too soon.}}

This comic humorously describes the changing view of what an {{w|atom}} is. This has happened so much it seems that we never really knew what we are looking at, and there have been many competing theories aside from the mainstream ones we are taught in school. He lists major depictions in the history of our understanding of an atom, and adds a few humorous ones in to poke fun at how diverse, contentious, and in retrospect often foolhardy, this history has been.

;Small hard ball model
The first model shown, in 1810, is said to be a "small hard ball model." Around this time, {{w|John Dalton}} published his textbook ''A New System of Chemical Philosophy'' which linked existing ideas of atomic theory and chemical reactivity to produce a combined {{w|Law of multiple proportions}} which proposed that each chemical element is comprised of a single unique type of atom, and introduced the concept of {{w|Molecular mass|molecular weight}}. Dalton's theories form the basis of what is known today as {{w|stoichiometry}}, which underpins chemical reactivity. As atoms were considered at this time to be the smallest possible division of matter the scientific community thought of them as "hard round balls" of different sizes; thus the name described here. The "small hard ball" model is still commonly used when teaching and discussing chemical molecules which do not require the level of detail provided by more advanced models, with atoms represented as small, hard, round balls connected by sticks representing chemical bonds.

;Plum pudding model
In the late 19th and early 20th centuries, the study of these "atom" things faced a crisis: where would the newly discovered "{{w|electron}}s" go? In 1904, physicist {{w|J. J. Thomson}}, who discovered electrons, had an idea: maybe the electrons were small point charges moving around in a big mass of positive charge. This was the "{{w|plum pudding model}}", the second model on the comic, called this because people imagined the positively charged mass as a "{{w|Christmas pudding|plum pudding}}". (The title text references Thomson as well, along with the humorous observation that plum puddings themselves are made of atoms.) The problem with this approach is that same charges generally repel, resulting in the more mobile or unbalanced charges forming a surface shell around the others, attempting to escape, rather than being content to being randomly distributed among them.

;Tiny bird model
There were many competing ideas in the formative years of what-are-atoms-made-of-ology, [[Randall]] makes up a 1907 "tiny bird model."

;Rutherford model
Ultimately, the tentative winner in the battle was the model of Thomson's student {{w|Ernest Rutherford}}, who discovered from electrostatic scattering experiments that the positive charge seemed to be concentrated in the center of the atom, and proposed his {{w|Rutherford model}}, or "planetary model", in 1911, where electrons orbit a very concentrated positive charge. This model has often been compared to the orbit of the planets around the sun, with the electrostatic attraction of the electrons and protons shaping the orbits, rather than gravity. This is the fourth model in the comic.

;Bohr model
The Rutherford model could not explain the discrete spectral lines in absorption and emission spectra. It also did not explain why electrons did not spiral in to the nucleus. {{w|Niels Bohr}} patched the model up by proposing that electrons could only exist in distinct "energy levels" at discrete distances from the nucleus. The 1913 "{{w|Bohr model}}", the fifth model shown here, was part of beginning quantum mechanics. Physics behaves differently at the small scale of atoms than the large scales we are more familiar with.

;Nunchuck model
Randall facetiously suggests a "{{w|Nunchaku|nunchuck}} model", the sixth model shown, of a packet of protons swinging a packet of electrons around. One can imagine a handle filled with electrons bonded by the strong nuclear force to a chain made of neutrons, bonded again by the strong nuclear force to a handle made of protons. The heavier protonic handle acts loosely as an orbital center as the electron-filled opposite handle swings wildly around it, attempting to resolve its electrostatic attraction within the restraints of its chain.

;Chadwick model
The next refinement was in the structure of the nucleus. Note that at this time, nobody thought of splitting up the nucleus into {{w|proton}}s and {{w|neutron}}s. But pretty soon people noticed that protons and neutrons existed; {{w|James Chadwick}}, who discovered the neutron, figured that the atom had a nucleus of neutrons and protons, along with a bunch of electrons orbiting around it in a Bohrish manner. This is what the layman today often thinks of as an atom, and is the seventh model shown here.

;538 Model
The eighth model shown is a made up "538 model," in 2008. {{w|FiveThirtyEight|538}} is a statistical analysis website that gained fame in 2008 for predicting every race but 2 correctly in the {{w|2008 United States presidential election|US presidential election}} and predicting every state and Obama's win in the 2012 election. Unlike most other media and polling institutes it saw a rather high probability of 29% for Trump to win the 2016 election by summing up the uncertainties in all the battle states. It has since been known for making mathematical models for everything; the model jokingly suggests that 538 has modeled and presumably made predictions about the atom. The {{w|pie chart}} shows the statistical composition of neutrons, protons and electrons, 38%, 31%, and 31% respectively. This could either be the average of a massive body with several isotopes or represent gallium-69, the most abundant {{w|Isotopes of gallium|isotope of gallium}}, with 31 protons, 31 electrons and 38 neutrons. FiveThirtyEight has previously been mentioned in several xkcd comics, including in [[477: Typewriter]], [[500: Election]], [[635: Locke and Demosthenes]], [[1130: Poll Watching]], [[1779: 2017]], and [[2002: LeBron James and Stephen Curry]]. It's appropriate to list the 538 model as a precursor to the quantum model, as it is a step towards considering the likelihood of different quantities of subatomic particles to be in different volumes of space, rather than considering them as strictly kinematic particles. The comic moves this development into 2008 in support of this joke, when it was actually made much earlier.

;Quantum model
But is the Chadwick model what scientists endorse today? No!
{{w|Maxwell's equations|The theory of electromagnetism}} says that accelerated charges, like the electrons circling, would lose energy emitted as electromagnetic waves and would quickly orbit into the nucleus. Bohr only postulated that this would not happen, but his model could not explain why. Another problem{{Citation needed}} is that atoms, even the hydrogen atom are not flat - which they would be, if a single electron orbited in a circular or elliptical trajectory (the circular motion of charge results in a magnetic moment; Otto Stern and Walter Gerlach {{w|Stern–Gerlach experiment|showed}} that independent from the direction of the measurement the angular momentum - for certain elements - always has the maximum positive or negative value, i.e. not only the radius, but also the angular momentum is quantized - and never zero. You cannot 'look at' the atom from above and 'see' the orbital circle. It always 'seems', as if you 'looked' from the side and would measure the full magnetic dipole. Stern and Gerlach actually saw the spin of an electron of the silver atom instead of the angular momentum, which is according to quantum mechanics 0).
Today (i.e. actually since 1926, 29 years after the discovery of the electron) physicists subscribe to a quantum model, which is the ninth model shown here. Instead of electrons with definite location and momentum (~speed), the parts of the atom are described by probability fields of possible locations and momentums. The changes in momentum probability normally cancel each other out, so there is no electromagnetic radiation. This is very abstract, and in the last model, the model is postulated to get so abstract that it is just a "small hard ball surrounded by math" model, the last model shown. This then is remarkably similar to the model we started out from, the "small hard ball model" (without the math).

;“Small hard ball surrounded by math” model
The picture for the "small ball surrounded by math" depicts a circle with several numbers around it. While the numbers seem to symbolize the "surrounding math" in a general sense, some of them suggest constants used in actual mathematical equations or other numbers related to the quantum model. The shapes and densities of the atomic orbitals are calculated with the {{w|Schrödinger equation}}, which is complex and difficult to solve. Or with string theory, which does not make it easier. For this reason atoms are generally precisely considered in only very simple simulations, and the details of interactions of many atoms at large scales that form our daily lives are incredibly hard to precisely understand and predict on an atomic level. It comes down to "these roundish things we call atoms are moving around in these approximate ways obeying this complex equation with too many numbers involved in most situations to accurately model, so let's use a different, empirically derived formula that describes the behavior of the system in general."

{| class="wikitable"
|-
! Number !! Explanation
|-
| 18 || Maximum number of electrons in the third (M) {{w|electron shell}}
|-
| 0.1 || 1/10th, a simple decimal
|-
| π || The {{w|Pi|number pi}} ratio of circumference of a circle to half its diameter. Pi is present in many physics equations, often as its double value (2π); also in the definition of the {{w|Planck_constant#Value|reduced Planck constant ħ (h bar)}} present in quantum-mechanical equations.
|-
| 173 || Could be the mass of the top quark in GeV/c². Or it could be the atomic number from which point {{w|Extended periodic table|supercritical atoms}} (the innermost electron shells of those supercritical atoms have such high binding energies that they {{w|Pair production|create electron-positron pairs from the vaccum}} and thus cannot be fully ionized) start. This atomic number can be calculated by a mathematical term and does not fit to a typical foundational physical theory. Alternatively, a typo, and it should be 137, referring to the fine structure constant which value is approximately 1/137. As an interesting aside, the start of the supercritical atoms would be exactly the fine-structure-constant 137, if the nucleus is assumed to have zero size, and in the Bohr model of such an atom the speed of the innermost electron would reach light speed.
|-
| √2 || An irrational constant, the square root of two, which comes up frequently
|-
| 4i || A simple complex number; i is considered the square root of -1 (4i is the square root of -16)
|}

==Transcript==
{{incomplete transcript|Do NOT delete this tag too soon.}}
:[One large panel with a caption centered on top and ten small drawings in two rows. Each drawing has a description below it.]

:'''Models of the Atom'''
:over time

:[A somewhat imperfectly drawn circle.]
:1810 Small hard ball model

:[A rounded-corners trapezoid inside which there are four small plus signs and four small circles with minus signs inside them.]
:1904 Plum pudding model

:[A bigger circle, with four birds on the surface and music notes above.]
:1907 Tiny bird model

:[A small circle with dots circling around it, drawn with paths.]
:1911 Rutherford model

:[A circle with a plus sign with three circles around it, each with a dot.]
:1913 Bohr model

:[A nunchuck swinging, with the left stick filled with circles with plus signs and the right stick filled with circles with minus signs.]
:1928 Nunchuck model

:[A nucleus with three circles around it, each with a dot.]
:1932 Chadwick model

:[A pie chart, where a part of it has a circle, a part of it has a circle with a minus sign and a part of it has a circle with a plus sign.]
:2008 538 model

:[A small circle with clover-like orbitals around it and surrounded by two outer partly dashed circles.]
:Today Quantum model

:[A circle surrounded with numbers.]
:Numbers: 18, 0.1, π, 173, √2, 4i
:Future "Small hard ball surrounded by math" model

{{comic discussion}}

[[Category:Charts]]
[[Category:Comics featuring real people]] 
[[Category:Physics]]
[[Category:Animals]]

2100: Models of the Atom

2019-01-30T08:43:36Z

172.68.110.46:

{{comic
| number = 2100
| date = January 18, 2019
| title = Models of the Atom
| image = models_of_the_atom.png
| titletext = J.J. Thompson won a Nobel Prize for his work in electricity in gases, but was unfairly passed over for his "An atom is plum pudding, and plum pudding is MADE of atoms! Duuuuude." theory.
}}

==Explanation==
{{incomplete|Created by a COMPLAINING EQUATION. Please mention here why this explanation isn't complete. Do NOT delete this tag too soon.}}

This comic humorously describes the changing view of what an {{w|atom}} is. This has happened so much it seems that we never really knew what we are looking at, and there have been many competing theories aside from the mainstream ones we are taught in school. He lists major depictions in the history of our understanding of an atom, and adds a few humorous ones in to poke fun at how diverse, contentious, and in retrospect often foolhardy, this history has been.

;Small hard ball model
The first model shown, in 1810, is said to be a "small hard ball model." Around this time, {{w|John Dalton}} published his textbook ''A New System of Chemical Philosophy'' which linked existing ideas of atomic theory and chemical reactivity to produce a combined {{w|Law of multiple proportions}} which proposed that each chemical element is comprised of a single unique type of atom, and introduced the concept of {{w|Molecular mass|molecular weight}}. Dalton's theories form the basis of what is known today as {{w|stoichiometry}}, which underpins chemical reactivity. As atoms were considered at this time to be the smallest possible division of matter the scientific community thought of them as "hard round balls" of different sizes; thus the name described here. The "small hard ball" model is still commonly used when teaching and discussing chemical molecules which do not require the level of detail provided by more advanced models, with atoms represented as small, hard, round balls connected by sticks representing chemical bonds.

;Plum pudding model
In the late 19th and early 20th centuries, the study of these "atom" things faced a crisis: where would the newly discovered "{{w|electron}}s" go? In 1904, physicist {{w|J. J. Thomson}}, who discovered electrons, had an idea: maybe the electrons were small point charges moving around in a big mass of positive charge. This was the "{{w|plum pudding model}}", the second model on the comic, called this because people imagined the positively charged mass as a "{{w|Christmas pudding|plum pudding}}". (The title text references Thomson as well, along with the humorous observation that plum puddings themselves are made of atoms.) The problem with this approach is that same charges generally repel, resulting in the more mobile or unbalanced charges forming a surface shell around the others, attempting to escape, rather than being content to being randomly distributed among them.

;Tiny bird model
There were many competing ideas in the formative years of what-are-atoms-made-of-ology, [[Randall]] makes up a 1907 "tiny bird model."

;Rutherford model
Ultimately, the tentative winner in the battle was the model of Thomson's student {{w|Ernest Rutherford}}, who discovered from electrostatic scattering experiments that the positive charge seemed to be concentrated in the center of the atom, and proposed his {{w|Rutherford model}}, or "planetary model", in 1911, where electrons orbit a very concentrated positive charge. This model has often been compared to the orbit of the planets around the sun, with the electrostatic attraction of the electrons and protons shaping the orbits, rather than gravity. This is the fourth model in the comic.

;Bohr model
The Rutherford model could not explain the discrete spectral lines in absorption and emission spectra. It also did not explain why electrons did not spiral in to the nucleus. {{w|Niels Bohr}} patched the model up by proposing that electrons could only exist in distinct "energy levels" at discrete distances from the nucleus. The 1913 "{{w|Bohr model}}", the fifth model shown here, was part of beginning quantum mechanics. Physics behaves differently at the small scale of atoms than the large scales we are more familiar with.

;Nunchuck model
Randall facetiously suggests a "{{w|Nunchaku|nunchuck}} model", the sixth model shown, of a packet of protons swinging a packet of electrons around. One can imagine a handle filled with electrons bonded by the strong nuclear force to a chain made of neutrons, bonded again by the strong nuclear force to a handle made of protons. The heavier protonic handle acts loosely as an orbital center as the electron-filled opposite handle swings wildly around it, attempting to resolve its electrostatic attraction within the restraints of its chain.

;Chadwick model
The next refinement was in the structure of the nucleus. Note that at this time, nobody thought of splitting up the nucleus into {{w|proton}}s and {{w|neutron}}s. But pretty soon people noticed that protons and neutrons existed; {{w|James Chadwick}}, who discovered the neutron, figured that the atom had a nucleus of neutrons and protons, along with a bunch of electrons orbiting around it in a Bohrish manner. This is what the layman today often thinks of as an atom, and is the seventh model shown here.

;538 Model
The eighth model shown is a made up "538 model," in 2008. {{w|FiveThirtyEight|538}} is a statistical analysis website that gained fame in 2008 for predicting every race but 2 correctly in the {{w|2008 United States presidential election|US presidential election}} and predicting every state and Obama's win in the 2012 election. Unlike most other media and polling institutes it saw a rather high probability of 29% for Trump to win the 2016 election by summing up the uncertainties in all the battle states. It has since been known for making mathematical models for everything; the model jokingly suggests that 538 has modeled and presumably made predictions about the atom. The {{w|pie chart}} shows the statistical composition of neutrons, protons and electrons, 38%, 31%, and 31% respectively. This could either be the average of a massive body with several isotopes or represent gallium-69, the most abundant {{w|Isotopes of gallium|isotope of gallium}}, with 31 protons, 31 electrons and 38 neutrons. FiveThirtyEight has previously been mentioned in several xkcd comics, including in [[477: Typewriter]], [[500: Election]], [[635: Locke and Demosthenes]], [[1130: Poll Watching]], [[1779: 2017]], and [[2002: LeBron James and Stephen Curry]]. It's appropriate to list the 538 model as a precursor to the quantum model, as it is a step towards considering the likelihood of different quantities of subatomic particles to be in different volumes of space, rather than considering them as strictly kinematic particles. The comic moves this development into 2008 in support of this joke, when it was actually made much earlier.

;Quantum model
But is the Chadwick model what scientists endorse today? No!
{{w|Maxwell's equations|The theory of electromagnetism}} says that accelerated charges, like the electrons circling, would lose energy emitted as electromagnetic waves and would quickly orbit into the nucleus. Bohr only postulated that this would not happen, but his model could not explain why. Another problem{{Citation needed}} is that atoms, even the hydrogen atom are not flat - which they would be, if a single electron orbited in a circular or elliptical trajectory (the circular motion of charge results in a magnetic moment; Otto Stern and Walter Gerlach {{w|Stern–Gerlach experiment|showed}} that independent from the direction of the measurement the angular momentum - for certain elements - always has the maximum positive or negative value, i.e. not only the radius, but also the angular momentum is quantized - and never zero. You cannot 'look at' the atom from above and 'see' the orbital circle. It always 'seems', as if you 'looked' from the side and would measure the full magnetic dipole. Stern and Gerlach actually saw the spin of an electron of the silver atom instead of the angular momentum, which is according to quantum mechanics 0).
Today (i.e. actually since 1926, 29 years after the discovery of the electron) physicists subscribe to a quantum model, which is the ninth model shown here. Instead of electrons with definite location and momentum (~speed), the parts of the atom are described by probability fields of possible locations and momentums. The changes in momentum probability normally cancel each other out, so there is no electromagnetic radiation. This is very abstract, and in the last model, the model is postulated to get so abstract that it is just a "small hard ball surrounded by math" model, the last model shown. This then is remarkably similar to the model we started out from, the "small hard ball model" (without the math).

;“Small hard ball surrounded by math” model
The picture for the "small ball surrounded by math" depicts a circle with several numbers around it. While the numbers seem to symbolize the "surrounding math" in a general sense, some of them suggest constants used in actual mathematical equations or other numbers related to the quantum model. The shapes and densities of the atomic orbitals are calculated with the {{w|Schrödinger equation}}, which is complex and difficult to solve. Or with string theory, which does not make it easier. For this reason atoms are generally precisely considered in only very simple simulations, and the details of interactions of many atoms at large scales that form our daily lives are incredibly hard to precisely understand and predict on an atomic level. It comes down to "these roundish things we call atoms are moving around in these approximate ways obeying this complex equation with too many numbers involved in most situations to accurately model, so let's use a different, empirically derived formula that describes the behavior of the system in general."

{| class="wikitable"
|-
! Number !! Explanation
|-
| 18 || Maximum number of electrons in the third (M) {{w|electron shell}}
|-
| 0.1 || 1/10th, a simple decimal
|-
| π || The {{w|Pi|number pi}} ratio of circumference of a circle to half its diameter. Pi is present in many physics equations, often as its double value (2π); also in the definition of the {{w|Planck_constant#Value|reduced Planck constant}} present in quantum-mechanical equations.
|-
| 173 || Could be the mass of the top quark in GeV/c². Or it could be the atomic number from which point {{w|Extended periodic table|supercritical atoms}} (the innermost electron shells of those supercritical atoms have such high binding energies that they {{w|Pair production|create electron-positron pairs from the vaccum}} and thus cannot be fully ionized) start. This atomic number can be calculated by a mathematical term and does not fit to a typical foundational physical theory. Alternatively, a typo, and it should be 137, referring to the fine structure constant which value is approximately 1/137. As an interesting aside, the start of the supercritical atoms would be exactly the fine-structure-constant 137, if the nucleus is assumed to have zero size, and in the Bohr model of such an atom the speed of the innermost electron would reach light speed.
|-
| √2 || An irrational constant, the square root of two, which comes up frequently
|-
| 4i || A simple complex number; i is considered the square root of -1 (4i is the square root of -16)
|}

==Transcript==
{{incomplete transcript|Do NOT delete this tag too soon.}}
:[One large panel with a caption centered on top and ten small drawings in two rows. Each drawing has a description below it.]

:'''Models of the Atom'''
:over time

:[A somewhat imperfectly drawn circle.]
:1810 Small hard ball model

:[A rounded-corners trapezoid inside which there are four small plus signs and four small circles with minus signs inside them.]
:1904 Plum pudding model

:[A bigger circle, with four birds on the surface and music notes above.]
:1907 Tiny bird model

:[A small circle with dots circling around it, drawn with paths.]
:1911 Rutherford model

:[A circle with a plus sign with three circles around it, each with a dot.]
:1913 Bohr model

:[A nunchuck swinging, with the left stick filled with circles with plus signs and the right stick filled with circles with minus signs.]
:1928 Nunchuck model

:[A nucleus with three circles around it, each with a dot.]
:1932 Chadwick model

:[A pie chart, where a part of it has a circle, a part of it has a circle with a minus sign and a part of it has a circle with a plus sign.]
:2008 538 model

:[A small circle with clover-like orbitals around it and surrounded by two outer partly dashed circles.]
:Today Quantum model

:[A circle surrounded with numbers.]
:Numbers: 18, 0.1, π, 173, √2, 4i
:Future "Small hard ball surrounded by math" model

{{comic discussion}}

[[Category:Charts]]
[[Category:Comics featuring real people]] 
[[Category:Physics]]
[[Category:Animals]]

2100: Models of the Atom

2019-01-30T08:42:35Z

172.68.110.46:

{{comic
| number = 2100
| date = January 18, 2019
| title = Models of the Atom
| image = models_of_the_atom.png
| titletext = J.J. Thompson won a Nobel Prize for his work in electricity in gases, but was unfairly passed over for his "An atom is plum pudding, and plum pudding is MADE of atoms! Duuuuude." theory.
}}

==Explanation==
{{incomplete|Created by a COMPLAINING EQUATION. Please mention here why this explanation isn't complete. Do NOT delete this tag too soon.}}

This comic humorously describes the changing view of what an {{w|atom}} is. This has happened so much it seems that we never really knew what we are looking at, and there have been many competing theories aside from the mainstream ones we are taught in school. He lists major depictions in the history of our understanding of an atom, and adds a few humorous ones in to poke fun at how diverse, contentious, and in retrospect often foolhardy, this history has been.

;Small hard ball model
The first model shown, in 1810, is said to be a "small hard ball model." Around this time, {{w|John Dalton}} published his textbook ''A New System of Chemical Philosophy'' which linked existing ideas of atomic theory and chemical reactivity to produce a combined {{w|Law of multiple proportions}} which proposed that each chemical element is comprised of a single unique type of atom, and introduced the concept of {{w|Molecular mass|molecular weight}}. Dalton's theories form the basis of what is known today as {{w|stoichiometry}}, which underpins chemical reactivity. As atoms were considered at this time to be the smallest possible division of matter the scientific community thought of them as "hard round balls" of different sizes; thus the name described here. The "small hard ball" model is still commonly used when teaching and discussing chemical molecules which do not require the level of detail provided by more advanced models, with atoms represented as small, hard, round balls connected by sticks representing chemical bonds.

;Plum pudding model
In the late 19th and early 20th centuries, the study of these "atom" things faced a crisis: where would the newly discovered "{{w|electron}}s" go? In 1904, physicist {{w|J. J. Thomson}}, who discovered electrons, had an idea: maybe the electrons were small point charges moving around in a big mass of positive charge. This was the "{{w|plum pudding model}}", the second model on the comic, called this because people imagined the positively charged mass as a "{{w|Christmas pudding|plum pudding}}". (The title text references Thomson as well, along with the humorous observation that plum puddings themselves are made of atoms.) The problem with this approach is that same charges generally repel, resulting in the more mobile or unbalanced charges forming a surface shell around the others, attempting to escape, rather than being content to being randomly distributed among them.

;Tiny bird model
There were many competing ideas in the formative years of what-are-atoms-made-of-ology, [[Randall]] makes up a 1907 "tiny bird model."

;Rutherford model
Ultimately, the tentative winner in the battle was the model of Thomson's student {{w|Ernest Rutherford}}, who discovered from electrostatic scattering experiments that the positive charge seemed to be concentrated in the center of the atom, and proposed his {{w|Rutherford model}}, or "planetary model", in 1911, where electrons orbit a very concentrated positive charge. This model has often been compared to the orbit of the planets around the sun, with the electrostatic attraction of the electrons and protons shaping the orbits, rather than gravity. This is the fourth model in the comic.

;Bohr model
The Rutherford model could not explain the discrete spectral lines in absorption and emission spectra. It also did not explain why electrons did not spiral in to the nucleus. {{w|Niels Bohr}} patched the model up by proposing that electrons could only exist in distinct "energy levels" at discrete distances from the nucleus. The 1913 "{{w|Bohr model}}", the fifth model shown here, was part of beginning quantum mechanics. Physics behaves differently at the small scale of atoms than the large scales we are more familiar with.

;Nunchuck model
Randall facetiously suggests a "{{w|Nunchaku|nunchuck}} model", the sixth model shown, of a packet of protons swinging a packet of electrons around. One can imagine a handle filled with electrons bonded by the strong nuclear force to a chain made of neutrons, bonded again by the strong nuclear force to a handle made of protons. The heavier protonic handle acts loosely as an orbital center as the electron-filled opposite handle swings wildly around it, attempting to resolve its electrostatic attraction within the restraints of its chain.

;Chadwick model
The next refinement was in the structure of the nucleus. Note that at this time, nobody thought of splitting up the nucleus into {{w|proton}}s and {{w|neutron}}s. But pretty soon people noticed that protons and neutrons existed; {{w|James Chadwick}}, who discovered the neutron, figured that the atom had a nucleus of neutrons and protons, along with a bunch of electrons orbiting around it in a Bohrish manner. This is what the layman today often thinks of as an atom, and is the seventh model shown here.

;538 Model
The eighth model shown is a made up "538 model," in 2008. {{w|FiveThirtyEight|538}} is a statistical analysis website that gained fame in 2008 for predicting every race but 2 correctly in the {{w|2008 United States presidential election|US presidential election}} and predicting every state and Obama's win in the 2012 election. Unlike most other media and polling institutes it saw a rather high probability of 29% for Trump to win the 2016 election by summing up the uncertainties in all the battle states. It has since been known for making mathematical models for everything; the model jokingly suggests that 538 has modeled and presumably made predictions about the atom. The {{w|pie chart}} shows the statistical composition of neutrons, protons and electrons, 38%, 31%, and 31% respectively. This could either be the average of a massive body with several isotopes or represent gallium-69, the most abundant {{w|Isotopes of gallium|isotope of gallium}}, with 31 protons, 31 electrons and 38 neutrons. FiveThirtyEight has previously been mentioned in several xkcd comics, including in [[477: Typewriter]], [[500: Election]], [[635: Locke and Demosthenes]], [[1130: Poll Watching]], [[1779: 2017]], and [[2002: LeBron James and Stephen Curry]]. It's appropriate to list the 538 model as a precursor to the quantum model, as it is a step towards considering the likelihood of different quantities of subatomic particles to be in different volumes of space, rather than considering them as strictly kinematic particles. The comic moves this development into 2008 in support of this joke, when it was actually made much earlier.

;Quantum model
But is the Chadwick model what scientists endorse today? No!
{{w|Maxwell's equations|The theory of electromagnetism}} says that accelerated charges, like the electrons circling, would lose energy emitted as electromagnetic waves and would quickly orbit into the nucleus. Bohr only postulated that this would not happen, but his model could not explain why. Another problem{{Citation needed}} is that atoms, even the hydrogen atom are not flat - which they would be, if a single electron orbited in a circular or elliptical trajectory (the circular motion of charge results in a magnetic moment; Otto Stern and Walter Gerlach {{w|Stern–Gerlach experiment|showed}} that independent from the direction of the measurement the angular momentum - for certain elements - always has the maximum positive or negative value, i.e. not only the radius, but also the angular momentum is quantized - and never zero. You cannot 'look at' the atom from above and 'see' the orbital circle. It always 'seems', as if you 'looked' from the side and would measure the full magnetic dipole. Stern and Gerlach actually saw the spin of an electron of the silver atom instead of the angular momentum, which is according to quantum mechanics 0).
Today (i.e. actually since 1926, 29 years after the discovery of the electron) physicists subscribe to a quantum model, which is the ninth model shown here. Instead of electrons with definite location and momentum (~speed), the parts of the atom are described by probability fields of possible locations and momentums. The changes in momentum probability normally cancel each other out, so there is no electromagnetic radiation. This is very abstract, and in the last model, the model is postulated to get so abstract that it is just a "small hard ball surrounded by math" model, the last model shown. This then is remarkably similar to the model we started out from, the "small hard ball model" (without the math).

;“Small hard ball surrounded by math” model
The picture for the "small ball surrounded by math" depicts a circle with several numbers around it. While the numbers seem to symbolize the "surrounding math" in a general sense, some of them suggest constants used in actual mathematical equations or other numbers related to the quantum model. The shapes and densities of the atomic orbitals are calculated with the {{w|Schrödinger equation}}, which is complex and difficult to solve. Or with string theory, which does not make it easier. For this reason atoms are generally precisely considered in only very simple simulations, and the details of interactions of many atoms at large scales that form our daily lives are incredibly hard to precisely understand and predict on an atomic level. It comes down to "these roundish things we call atoms are moving around in these approximate ways obeying this complex equation with too many numbers involved in most situations to accurately model, so let's use a different, empirically derived formula that describes the behavior of the system in general."

{| class="wikitable"
|-
! Number !! Explanation
|-
| 18 || Maximum number of electrons in the third (M) {{w|electron shell}}
|-
| 0.1 || 1/10th, a simple decimal
|-
| π || The {{w|Pi|number pi}} ratio of circumference of a circle to half its diameter. Pi is present in many physics equations, often as its double value (2π); also in the definition of the {{w|Planck_constant#Value|reduced Planck constant}} present in quantum-mechanical equations.
|-
| 173 || Could be the mass of the top quark in GeV/c². Or it could be the atomic number from which point {{w|Extended periodic table|supercritical atoms}} (the innermost electron shells of those supercritical atoms have such high binding energies that they {{w|Pair production|create electron-positron pairs from the vaccum}} and thus cannot be fully ionized) start. This atomic number can be calculated by a mathematical term and does not fit to a typical foundational physical theory. Alternatively, a typo, and it should be 137, referring to the fine structure constant which value is approximately 1/137. As an interesting aside, the start of the supercritical atoms would be exactly the fine-structure-constant 137, if the nucleus is assumed to have no size, and in the Bohr model the speed of the innermost electron would reach light speed.
|-
| √2 || An irrational constant, the square root of two, which comes up frequently
|-
| 4i || A simple complex number; i is considered the square root of -1 (4i is the square root of -16)
|}

==Transcript==
{{incomplete transcript|Do NOT delete this tag too soon.}}
:[One large panel with a caption centered on top and ten small drawings in two rows. Each drawing has a description below it.]

:'''Models of the Atom'''
:over time

:[A somewhat imperfectly drawn circle.]
:1810 Small hard ball model

:[A rounded-corners trapezoid inside which there are four small plus signs and four small circles with minus signs inside them.]
:1904 Plum pudding model

:[A bigger circle, with four birds on the surface and music notes above.]
:1907 Tiny bird model

:[A small circle with dots circling around it, drawn with paths.]
:1911 Rutherford model

:[A circle with a plus sign with three circles around it, each with a dot.]
:1913 Bohr model

:[A nunchuck swinging, with the left stick filled with circles with plus signs and the right stick filled with circles with minus signs.]
:1928 Nunchuck model

:[A nucleus with three circles around it, each with a dot.]
:1932 Chadwick model

:[A pie chart, where a part of it has a circle, a part of it has a circle with a minus sign and a part of it has a circle with a plus sign.]
:2008 538 model

:[A small circle with clover-like orbitals around it and surrounded by two outer partly dashed circles.]
:Today Quantum model

:[A circle surrounded with numbers.]
:Numbers: 18, 0.1, π, 173, √2, 4i
:Future "Small hard ball surrounded by math" model

{{comic discussion}}

[[Category:Charts]]
[[Category:Comics featuring real people]] 
[[Category:Physics]]
[[Category:Animals]]

2100: Models of the Atom

2019-01-30T08:40:56Z

172.68.110.46:

{{comic
| number = 2100
| date = January 18, 2019
| title = Models of the Atom
| image = models_of_the_atom.png
| titletext = J.J. Thompson won a Nobel Prize for his work in electricity in gases, but was unfairly passed over for his "An atom is plum pudding, and plum pudding is MADE of atoms! Duuuuude." theory.
}}

==Explanation==
{{incomplete|Created by a COMPLAINING EQUATION. Please mention here why this explanation isn't complete. Do NOT delete this tag too soon.}}

This comic humorously describes the changing view of what an {{w|atom}} is. This has happened so much it seems that we never really knew what we are looking at, and there have been many competing theories aside from the mainstream ones we are taught in school. He lists major depictions in the history of our understanding of an atom, and adds a few humorous ones in to poke fun at how diverse, contentious, and in retrospect often foolhardy, this history has been.

;Small hard ball model
The first model shown, in 1810, is said to be a "small hard ball model." Around this time, {{w|John Dalton}} published his textbook ''A New System of Chemical Philosophy'' which linked existing ideas of atomic theory and chemical reactivity to produce a combined {{w|Law of multiple proportions}} which proposed that each chemical element is comprised of a single unique type of atom, and introduced the concept of {{w|Molecular mass|molecular weight}}. Dalton's theories form the basis of what is known today as {{w|stoichiometry}}, which underpins chemical reactivity. As atoms were considered at this time to be the smallest possible division of matter the scientific community thought of them as "hard round balls" of different sizes; thus the name described here. The "small hard ball" model is still commonly used when teaching and discussing chemical molecules which do not require the level of detail provided by more advanced models, with atoms represented as small, hard, round balls connected by sticks representing chemical bonds.

;Plum pudding model
In the late 19th and early 20th centuries, the study of these "atom" things faced a crisis: where would the newly discovered "{{w|electron}}s" go? In 1904, physicist {{w|J. J. Thomson}}, who discovered electrons, had an idea: maybe the electrons were small point charges moving around in a big mass of positive charge. This was the "{{w|plum pudding model}}", the second model on the comic, called this because people imagined the positively charged mass as a "{{w|Christmas pudding|plum pudding}}". (The title text references Thomson as well, along with the humorous observation that plum puddings themselves are made of atoms.) The problem with this approach is that same charges generally repel, resulting in the more mobile or unbalanced charges forming a surface shell around the others, attempting to escape, rather than being content to being randomly distributed among them.

;Tiny bird model
There were many competing ideas in the formative years of what-are-atoms-made-of-ology, [[Randall]] makes up a 1907 "tiny bird model."

;Rutherford model
Ultimately, the tentative winner in the battle was the model of Thomson's student {{w|Ernest Rutherford}}, who discovered from electrostatic scattering experiments that the positive charge seemed to be concentrated in the center of the atom, and proposed his {{w|Rutherford model}}, or "planetary model", in 1911, where electrons orbit a very concentrated positive charge. This model has often been compared to the orbit of the planets around the sun, with the electrostatic attraction of the electrons and protons shaping the orbits, rather than gravity. This is the fourth model in the comic.

;Bohr model
The Rutherford model could not explain the discrete spectral lines in absorption and emission spectra. It also did not explain why electrons did not spiral in to the nucleus. {{w|Niels Bohr}} patched the model up by proposing that electrons could only exist in distinct "energy levels" at discrete distances from the nucleus. The 1913 "{{w|Bohr model}}", the fifth model shown here, was part of beginning quantum mechanics. Physics behaves differently at the small scale of atoms than the large scales we are more familiar with.

;Nunchuck model
Randall facetiously suggests a "{{w|Nunchaku|nunchuck}} model", the sixth model shown, of a packet of protons swinging a packet of electrons around. One can imagine a handle filled with electrons bonded by the strong nuclear force to a chain made of neutrons, bonded again by the strong nuclear force to a handle made of protons. The heavier protonic handle acts loosely as an orbital center as the electron-filled opposite handle swings wildly around it, attempting to resolve its electrostatic attraction within the restraints of its chain.

;Chadwick model
The next refinement was in the structure of the nucleus. Note that at this time, nobody thought of splitting up the nucleus into {{w|proton}}s and {{w|neutron}}s. But pretty soon people noticed that protons and neutrons existed; {{w|James Chadwick}}, who discovered the neutron, figured that the atom had a nucleus of neutrons and protons, along with a bunch of electrons orbiting around it in a Bohrish manner. This is what the layman today often thinks of as an atom, and is the seventh model shown here.

;538 Model
The eighth model shown is a made up "538 model," in 2008. {{w|FiveThirtyEight|538}} is a statistical analysis website that gained fame in 2008 for predicting every race but 2 correctly in the {{w|2008 United States presidential election|US presidential election}} and predicting every state and Obama's win in the 2012 election. Unlike most other media and polling institutes it saw a rather high probability of 29% for Trump to win the 2016 election by summing up the uncertainties in all the battle states. It has since been known for making mathematical models for everything; the model jokingly suggests that 538 has modeled and presumably made predictions about the atom. The {{w|pie chart}} shows the statistical composition of neutrons, protons and electrons, 38%, 31%, and 31% respectively. This could either be the average of a massive body with several isotopes or represent gallium-69, the most abundant {{w|Isotopes of gallium|isotope of gallium}}, with 31 protons, 31 electrons and 38 neutrons. FiveThirtyEight has previously been mentioned in several xkcd comics, including in [[477: Typewriter]], [[500: Election]], [[635: Locke and Demosthenes]], [[1130: Poll Watching]], [[1779: 2017]], and [[2002: LeBron James and Stephen Curry]]. It's appropriate to list the 538 model as a precursor to the quantum model, as it is a step towards considering the likelihood of different quantities of subatomic particles to be in different volumes of space, rather than considering them as strictly kinematic particles. The comic moves this development into 2008 in support of this joke, when it was actually made much earlier.

;Quantum model
But is the Chadwick model what scientists endorse today? No!
{{w|Maxwell's equations|The theory of electromagnetism}} says that accelerated charges, like the electrons circling, would lose energy emitted as electromagnetic waves and would quickly orbit into the nucleus. Bohr only postulated that this would not happen, but his model could not explain why. Another problem{{Citation needed}} is that atoms, even the hydrogen atom are not flat - which they would be, if a single electron orbited in a circular or elliptical trajectory (the circular motion of charge results in a magnetic moment; Otto Stern and Walter Gerlach {{w|Stern–Gerlach experiment|showed}} that independent from the direction of the measurement the angular momentum - for certain elements - always has the maximum positive or negative value, i.e. not only the radius, but also the angular momentum is quantized - and never zero. You cannot 'look at' the atom from above and 'see' the orbital circle. It always 'seems', as if you 'looked' from the side and would measure the full magnetic dipole. Stern and Gerlach actually saw the spin of an electron of the silver atom instead of the angular momentum, which is according to quantum mechanics 0).
Today (i.e. actually since 1926, 29 years after the discovery of the electron) physicists subscribe to a quantum model, which is the ninth model shown here. Instead of electrons with definite location and momentum (~speed), the parts of the atom are described by probability fields of possible locations and momentums. The changes in momentum probability normally cancel each other out, so there is no electromagnetic radiation. This is very abstract, and in the last model, the model is postulated to get so abstract that it is just a "small hard ball surrounded by math" model, the last model shown. This then is remarkably similar to the model we started out from, the "small hard ball model" (without the math).

;“Small hard ball surrounded by math” model
The picture for the "small ball surrounded by math" depicts a circle with several numbers around it. While the numbers seem to symbolize the "surrounding math" in a general sense, some of them suggest constants used in actual mathematical equations or other numbers related to the quantum model. The shapes and densities of the atomic orbitals are calculated with the {{w|Schrödinger equation}}, which is complex and difficult to solve. Or with string theory, which does not make it easier. For this reason atoms are generally precisely considered in only very simple simulations, and the details of interactions of many atoms at large scales that form our daily lives are incredibly hard to precisely understand and predict on an atomic level. It comes down to "these roundish things we call atoms are moving around in these approximate ways obeying this complex equation with too many numbers involved in most situations to accurately model, so let's use a different, empirically derived formula that describes the behavior of the system in general."

{| class="wikitable"
|-
! Number !! Explanation
|-
| 18 || Maximum number of electrons in the third (M) {{w|electron shell}}
|-
| 0.1 || 1/10th, a simple decimal
|-
| π || The {{w|Pi|number pi}} ratio of circumference of a circle to half its diameter. Pi is present in many physics equations, often as its double value (2π); also in the definition of the {{w|Planck_constant#Value|reduced Planck constant}} present in quantum-mechanical equations.
|-
| 173 || Could be the mass of the top quark in GeV/c². Or it could be the atomic number from which point {{w|Extended periodic table|supercritical atoms}} (the innermost electron shells of those supercritical atoms have such high binding energies that they {{w|Pair production|create electron-positron pairs from the vaccum}} and thus cannot be fully ionized) start. This atomic number can be calculated by a mathematical term and does not fit to a typical foundational physical theory. Alternatively, a typo, and it should be 137, referring to the fine structure constant which value is approximately 1/137. As an interesting aside, the start of the supercritical atoms would be exactly the fine-structure-constant 137, if the nucleus is assumed to have no size.
|-
| √2 || An irrational constant, the square root of two, which comes up frequently
|-
| 4i || A simple complex number; i is considered the square root of -1 (4i is the square root of -16)
|}

==Transcript==
{{incomplete transcript|Do NOT delete this tag too soon.}}
:[One large panel with a caption centered on top and ten small drawings in two rows. Each drawing has a description below it.]

:'''Models of the Atom'''
:over time

:[A somewhat imperfectly drawn circle.]
:1810 Small hard ball model

:[A rounded-corners trapezoid inside which there are four small plus signs and four small circles with minus signs inside them.]
:1904 Plum pudding model

:[A bigger circle, with four birds on the surface and music notes above.]
:1907 Tiny bird model

:[A small circle with dots circling around it, drawn with paths.]
:1911 Rutherford model

:[A circle with a plus sign with three circles around it, each with a dot.]
:1913 Bohr model

:[A nunchuck swinging, with the left stick filled with circles with plus signs and the right stick filled with circles with minus signs.]
:1928 Nunchuck model

:[A nucleus with three circles around it, each with a dot.]
:1932 Chadwick model

:[A pie chart, where a part of it has a circle, a part of it has a circle with a minus sign and a part of it has a circle with a plus sign.]
:2008 538 model

:[A small circle with clover-like orbitals around it and surrounded by two outer partly dashed circles.]
:Today Quantum model

:[A circle surrounded with numbers.]
:Numbers: 18, 0.1, π, 173, √2, 4i
:Future "Small hard ball surrounded by math" model

{{comic discussion}}

[[Category:Charts]]
[[Category:Comics featuring real people]] 
[[Category:Physics]]
[[Category:Animals]]

2100: Models of the Atom

2019-01-30T08:39:53Z

172.68.110.46:

{{comic
| number = 2100
| date = January 18, 2019
| title = Models of the Atom
| image = models_of_the_atom.png
| titletext = J.J. Thompson won a Nobel Prize for his work in electricity in gases, but was unfairly passed over for his "An atom is plum pudding, and plum pudding is MADE of atoms! Duuuuude." theory.
}}

==Explanation==
{{incomplete|Created by a COMPLAINING EQUATION. Please mention here why this explanation isn't complete. Do NOT delete this tag too soon.}}

This comic humorously describes the changing view of what an {{w|atom}} is. This has happened so much it seems that we never really knew what we are looking at, and there have been many competing theories aside from the mainstream ones we are taught in school. He lists major depictions in the history of our understanding of an atom, and adds a few humorous ones in to poke fun at how diverse, contentious, and in retrospect often foolhardy, this history has been.

;Small hard ball model
The first model shown, in 1810, is said to be a "small hard ball model." Around this time, {{w|John Dalton}} published his textbook ''A New System of Chemical Philosophy'' which linked existing ideas of atomic theory and chemical reactivity to produce a combined {{w|Law of multiple proportions}} which proposed that each chemical element is comprised of a single unique type of atom, and introduced the concept of {{w|Molecular mass|molecular weight}}. Dalton's theories form the basis of what is known today as {{w|stoichiometry}}, which underpins chemical reactivity. As atoms were considered at this time to be the smallest possible division of matter the scientific community thought of them as "hard round balls" of different sizes; thus the name described here. The "small hard ball" model is still commonly used when teaching and discussing chemical molecules which do not require the level of detail provided by more advanced models, with atoms represented as small, hard, round balls connected by sticks representing chemical bonds.

;Plum pudding model
In the late 19th and early 20th centuries, the study of these "atom" things faced a crisis: where would the newly discovered "{{w|electron}}s" go? In 1904, physicist {{w|J. J. Thomson}}, who discovered electrons, had an idea: maybe the electrons were small point charges moving around in a big mass of positive charge. This was the "{{w|plum pudding model}}", the second model on the comic, called this because people imagined the positively charged mass as a "{{w|Christmas pudding|plum pudding}}". (The title text references Thomson as well, along with the humorous observation that plum puddings themselves are made of atoms.) The problem with this approach is that same charges generally repel, resulting in the more mobile or unbalanced charges forming a surface shell around the others, attempting to escape, rather than being content to being randomly distributed among them.

;Tiny bird model
There were many competing ideas in the formative years of what-are-atoms-made-of-ology, [[Randall]] makes up a 1907 "tiny bird model."

;Rutherford model
Ultimately, the tentative winner in the battle was the model of Thomson's student {{w|Ernest Rutherford}}, who discovered from electrostatic scattering experiments that the positive charge seemed to be concentrated in the center of the atom, and proposed his {{w|Rutherford model}}, or "planetary model", in 1911, where electrons orbit a very concentrated positive charge. This model has often been compared to the orbit of the planets around the sun, with the electrostatic attraction of the electrons and protons shaping the orbits, rather than gravity. This is the fourth model in the comic.

;Bohr model
The Rutherford model could not explain the discrete spectral lines in absorption and emission spectra. It also did not explain why electrons did not spiral in to the nucleus. {{w|Niels Bohr}} patched the model up by proposing that electrons could only exist in distinct "energy levels" at discrete distances from the nucleus. The 1913 "{{w|Bohr model}}", the fifth model shown here, was part of beginning quantum mechanics. Physics behaves differently at the small scale of atoms than the large scales we are more familiar with.

;Nunchuck model
Randall facetiously suggests a "{{w|Nunchaku|nunchuck}} model", the sixth model shown, of a packet of protons swinging a packet of electrons around. One can imagine a handle filled with electrons bonded by the strong nuclear force to a chain made of neutrons, bonded again by the strong nuclear force to a handle made of protons. The heavier protonic handle acts loosely as an orbital center as the electron-filled opposite handle swings wildly around it, attempting to resolve its electrostatic attraction within the restraints of its chain.

;Chadwick model
The next refinement was in the structure of the nucleus. Note that at this time, nobody thought of splitting up the nucleus into {{w|proton}}s and {{w|neutron}}s. But pretty soon people noticed that protons and neutrons existed; {{w|James Chadwick}}, who discovered the neutron, figured that the atom had a nucleus of neutrons and protons, along with a bunch of electrons orbiting around it in a Bohrish manner. This is what the layman today often thinks of as an atom, and is the seventh model shown here.

;538 Model
The eighth model shown is a made up "538 model," in 2008. {{w|FiveThirtyEight|538}} is a statistical analysis website that gained fame in 2008 for predicting every race but 2 correctly in the {{w|2008 United States presidential election|US presidential election}} and predicting every state and Obama's win in the 2012 election. Unlike most other media and polling institutes it saw a rather high probability of 29% for Trump to win the 2016 election by summing up the uncertainties in all the battle states. It has since been known for making mathematical models for everything; the model jokingly suggests that 538 has modeled and presumably made predictions about the atom. The {{w|pie chart}} shows the statistical composition of neutrons, protons and electrons, 38%, 31%, and 31% respectively. This could either be the average of a massive body with several isotopes or represent gallium-69, the most abundant {{w|Isotopes of gallium|isotope of gallium}}, with 31 protons, 31 electrons and 38 neutrons. FiveThirtyEight has previously been mentioned in several xkcd comics, including in [[477: Typewriter]], [[500: Election]], [[635: Locke and Demosthenes]], [[1130: Poll Watching]], [[1779: 2017]], and [[2002: LeBron James and Stephen Curry]]. It's appropriate to list the 538 model as a precursor to the quantum model, as it is a step towards considering the likelihood of different quantities of subatomic particles to be in different volumes of space, rather than considering them as strictly kinematic particles. The comic moves this development into 2008 in support of this joke, when it was actually made much earlier.

;Quantum model
But is the Chadwick model what scientists endorse today? No!
{{w|Maxwell's equations|The theory of electromagnetism}} says that accelerated charges, like the electrons circling, would lose energy emitted as electromagnetic waves and would quickly orbit into the nucleus. Bohr only postulated that this would not happen, but his model could not explain why. Another problem{{Citation needed}} is that atoms, even the hydrogen atom are not flat - which they would be, if a single electron orbited in a circular or elliptical trajectory (the circular motion of charge results in a magnetic moment; Otto Stern and Walter Gerlach {{w|Stern–Gerlach experiment|showed}} that independent from the direction of the measurement the angular momentum - for certain elements - always has the maximum positive or negative value, i.e. not only the radius, but also the angular momentum is quantized - and never zero. You cannot 'look at' the atom from above and 'see' the orbital circle. It always 'seems', as if you 'looked' from the side and would measure the full magnetic dipole. Stern and Gerlach actually saw the spin of an electron of the silver atom instead of the angular momentum, which is according to quantum mechanics 0).
Today (i.e. actually since 1926, 29 years after the discovery of the electron) physicists subscribe to a quantum model, which is the ninth model shown here. Instead of electrons with definite location and momentum (~speed), the parts of the atom are described by probability fields of possible locations and momentums. The changes in momentum probability normally cancel each other out, so there is no electromagnetic radiation. This is very abstract, and in the last model, the model is postulated to get so abstract that it is just a "small hard ball surrounded by math" model, the last model shown. This then is remarkably similar to the model we started out from, the "small hard ball model" (without the math).

;“Small hard ball surrounded by math” model
The picture for the "small ball surrounded by math" depicts a circle with several numbers around it. While the numbers seem to symbolize the "surrounding math" in a general sense, some of them suggest constants used in actual mathematical equations or other numbers related to the quantum model. The shapes and densities of the atomic orbitals are calculated with the {{w|Schrödinger equation}}, which is complex and difficult to solve. Or with string theory, which does not make it easier. For this reason atoms are generally precisely considered in only very simple simulations, and the details of interactions of many atoms at large scales that form our daily lives are incredibly hard to precisely understand and predict on an atomic level. It comes down to "these roundish things we call atoms are moving around in these approximate ways obeying this complex equation with too many numbers involved in most situations to accurately model, so let's use a different, empirically derived formula that describes the behavior of the system in general."

{| class="wikitable"
|-
! Number !! Explanation
|-
| 18 || Maximum number of electrons in the third (M) {{w|electron shell}}
|-
| 0.1 || 1/10th, a simple decimal
|-
| π || The {{w|Pi|number pi}} ratio of circumference of a circle to half its diameter. Pi is present in many physics equations, often as its double value (2π); also in the definition of the {{w|Planck_constant#Value|reduced Planck constant}} present in quantum-mechanical equations.
|-
| 173 || Could be the mass of the top quark in GeV/c². Or it could be the atomic number from which point {{w|Extended periodic table|supercritical atoms}} (the innermost electron shells of those supercritical atoms have such high binding energies that they {{w|Pair production|create electron-positron pairs from the vaccum}} and thus cannot be fully ionized) start. This atomic number can be calculated by a mathematical term and does not fit to a typical foundational physical theory). Alternatively, a typo, and it should be 137, referring to the fine structure constant which value is approximately 1/137. As an interesting aside the start of the supercritical atoms would be exactly the fine-structure-constant 137, if the nucleus is assumed to have size.
|-
| √2 || An irrational constant, the square root of two, which comes up frequently
|-
| 4i || A simple complex number; i is considered the square root of -1 (4i is the square root of -16)
|}

==Transcript==
{{incomplete transcript|Do NOT delete this tag too soon.}}
:[One large panel with a caption centered on top and ten small drawings in two rows. Each drawing has a description below it.]

:'''Models of the Atom'''
:over time

:[A somewhat imperfectly drawn circle.]
:1810 Small hard ball model

:[A rounded-corners trapezoid inside which there are four small plus signs and four small circles with minus signs inside them.]
:1904 Plum pudding model

:[A bigger circle, with four birds on the surface and music notes above.]
:1907 Tiny bird model

:[A small circle with dots circling around it, drawn with paths.]
:1911 Rutherford model

:[A circle with a plus sign with three circles around it, each with a dot.]
:1913 Bohr model

:[A nunchuck swinging, with the left stick filled with circles with plus signs and the right stick filled with circles with minus signs.]
:1928 Nunchuck model

:[A nucleus with three circles around it, each with a dot.]
:1932 Chadwick model

:[A pie chart, where a part of it has a circle, a part of it has a circle with a minus sign and a part of it has a circle with a plus sign.]
:2008 538 model

:[A small circle with clover-like orbitals around it and surrounded by two outer partly dashed circles.]
:Today Quantum model

:[A circle surrounded with numbers.]
:Numbers: 18, 0.1, π, 173, √2, 4i
:Future "Small hard ball surrounded by math" model

{{comic discussion}}

[[Category:Charts]]
[[Category:Comics featuring real people]] 
[[Category:Physics]]
[[Category:Animals]]

2100: Models of the Atom

2019-01-30T08:38:26Z

172.68.110.46:

{{comic
| number = 2100
| date = January 18, 2019
| title = Models of the Atom
| image = models_of_the_atom.png
| titletext = J.J. Thompson won a Nobel Prize for his work in electricity in gases, but was unfairly passed over for his "An atom is plum pudding, and plum pudding is MADE of atoms! Duuuuude." theory.
}}

==Explanation==
{{incomplete|Created by a COMPLAINING EQUATION. Please mention here why this explanation isn't complete. Do NOT delete this tag too soon.}}

This comic humorously describes the changing view of what an {{w|atom}} is. This has happened so much it seems that we never really knew what we are looking at, and there have been many competing theories aside from the mainstream ones we are taught in school. He lists major depictions in the history of our understanding of an atom, and adds a few humorous ones in to poke fun at how diverse, contentious, and in retrospect often foolhardy, this history has been.

;Small hard ball model
The first model shown, in 1810, is said to be a "small hard ball model." Around this time, {{w|John Dalton}} published his textbook ''A New System of Chemical Philosophy'' which linked existing ideas of atomic theory and chemical reactivity to produce a combined {{w|Law of multiple proportions}} which proposed that each chemical element is comprised of a single unique type of atom, and introduced the concept of {{w|Molecular mass|molecular weight}}. Dalton's theories form the basis of what is known today as {{w|stoichiometry}}, which underpins chemical reactivity. As atoms were considered at this time to be the smallest possible division of matter the scientific community thought of them as "hard round balls" of different sizes; thus the name described here. The "small hard ball" model is still commonly used when teaching and discussing chemical molecules which do not require the level of detail provided by more advanced models, with atoms represented as small, hard, round balls connected by sticks representing chemical bonds.

;Plum pudding model
In the late 19th and early 20th centuries, the study of these "atom" things faced a crisis: where would the newly discovered "{{w|electron}}s" go? In 1904, physicist {{w|J. J. Thomson}}, who discovered electrons, had an idea: maybe the electrons were small point charges moving around in a big mass of positive charge. This was the "{{w|plum pudding model}}", the second model on the comic, called this because people imagined the positively charged mass as a "{{w|Christmas pudding|plum pudding}}". (The title text references Thomson as well, along with the humorous observation that plum puddings themselves are made of atoms.) The problem with this approach is that same charges generally repel, resulting in the more mobile or unbalanced charges forming a surface shell around the others, attempting to escape, rather than being content to being randomly distributed among them.

;Tiny bird model
There were many competing ideas in the formative years of what-are-atoms-made-of-ology, [[Randall]] makes up a 1907 "tiny bird model."

;Rutherford model
Ultimately, the tentative winner in the battle was the model of Thomson's student {{w|Ernest Rutherford}}, who discovered from electrostatic scattering experiments that the positive charge seemed to be concentrated in the center of the atom, and proposed his {{w|Rutherford model}}, or "planetary model", in 1911, where electrons orbit a very concentrated positive charge. This model has often been compared to the orbit of the planets around the sun, with the electrostatic attraction of the electrons and protons shaping the orbits, rather than gravity. This is the fourth model in the comic.

;Bohr model
The Rutherford model could not explain the discrete spectral lines in absorption and emission spectra. It also did not explain why electrons did not spiral in to the nucleus. {{w|Niels Bohr}} patched the model up by proposing that electrons could only exist in distinct "energy levels" at discrete distances from the nucleus. The 1913 "{{w|Bohr model}}", the fifth model shown here, was part of beginning quantum mechanics. Physics behaves differently at the small scale of atoms than the large scales we are more familiar with.

;Nunchuck model
Randall facetiously suggests a "{{w|Nunchaku|nunchuck}} model", the sixth model shown, of a packet of protons swinging a packet of electrons around. One can imagine a handle filled with electrons bonded by the strong nuclear force to a chain made of neutrons, bonded again by the strong nuclear force to a handle made of protons. The heavier protonic handle acts loosely as an orbital center as the electron-filled opposite handle swings wildly around it, attempting to resolve its electrostatic attraction within the restraints of its chain.

;Chadwick model
The next refinement was in the structure of the nucleus. Note that at this time, nobody thought of splitting up the nucleus into {{w|proton}}s and {{w|neutron}}s. But pretty soon people noticed that protons and neutrons existed; {{w|James Chadwick}}, who discovered the neutron, figured that the atom had a nucleus of neutrons and protons, along with a bunch of electrons orbiting around it in a Bohrish manner. This is what the layman today often thinks of as an atom, and is the seventh model shown here.

;538 Model
The eighth model shown is a made up "538 model," in 2008. {{w|FiveThirtyEight|538}} is a statistical analysis website that gained fame in 2008 for predicting every race but 2 correctly in the {{w|2008 United States presidential election|US presidential election}} and predicting every state and Obama's win in the 2012 election. Unlike most other media and polling institutes it saw a rather high probability of 29% for Trump to win the 2016 election by summing up the uncertainties in all the battle states. It has since been known for making mathematical models for everything; the model jokingly suggests that 538 has modeled and presumably made predictions about the atom. The {{w|pie chart}} shows the statistical composition of neutrons, protons and electrons, 38%, 31%, and 31% respectively. This could either be the average of a massive body with several isotopes or represent gallium-69, the most abundant {{w|Isotopes of gallium|isotope of gallium}}, with 31 protons, 31 electrons and 38 neutrons. FiveThirtyEight has previously been mentioned in several xkcd comics, including in [[477: Typewriter]], [[500: Election]], [[635: Locke and Demosthenes]], [[1130: Poll Watching]], [[1779: 2017]], and [[2002: LeBron James and Stephen Curry]]. It's appropriate to list the 538 model as a precursor to the quantum model, as it is a step towards considering the likelihood of different quantities of subatomic particles to be in different volumes of space, rather than considering them as strictly kinematic particles. The comic moves this development into 2008 in support of this joke, when it was actually made much earlier.

;Quantum model
But is the Chadwick model what scientists endorse today? No!
{{w|Maxwell's equations|The theory of electromagnetism}} says that accelerated charges, like the electrons circling, would lose energy emitted as electromagnetic waves and would quickly orbit into the nucleus. Bohr only postulated that this would not happen, but his model could not explain why. Another problem{{Citation needed}} is that atoms, even the hydrogen atom are not flat - which they would be, if a single electron orbited in a circular or elliptical trajectory (the circular motion of charge results in a magnetic moment; Otto Stern and Walter Gerlach {{w|Stern–Gerlach experiment|showed}} that independent from the direction of the measurement the angular momentum - for certain elements - always has the maximum positive or negative value, i.e. not only the radius, but also the angular momentum is quantized - and never zero. You cannot 'look at' the atom from above and 'see' the orbital circle. It always 'seems', as if you 'looked' from the side and would measure the full magnetic dipole. Stern and Gerlach actually saw the spin of an electron of the silver atom instead of the angular momentum, which is according to quantum mechanics 0).
Today (i.e. actually since 1926, 29 years after the discovery of the electron) physicists subscribe to a quantum model, which is the ninth model shown here. Instead of electrons with definite location and momentum (~speed), the parts of the atom are described by probability fields of possible locations and momentums. The changes in momentum probability normally cancel each other out, so there is no electromagnetic radiation. This is very abstract, and in the last model, the model is postulated to get so abstract that it is just a "small hard ball surrounded by math" model, the last model shown. This then is remarkably similar to the model we started out from, the "small hard ball model" (without the math).

;“Small hard ball surrounded by math” model
The picture for the "small ball surrounded by math" depicts a circle with several numbers around it. While the numbers seem to symbolize the "surrounding math" in a general sense, some of them suggest constants used in actual mathematical equations or other numbers related to the quantum model. The shapes and densities of the atomic orbitals are calculated with the {{w|Schrödinger equation}}, which is complex and difficult to solve. Or with string theory, which does not make it easier. For this reason atoms are generally precisely considered in only very simple simulations, and the details of interactions of many atoms at large scales that form our daily lives are incredibly hard to precisely understand and predict on an atomic level. It comes down to "these roundish things we call atoms are moving around in these approximate ways obeying this complex equation with too many numbers involved in most situations to accurately model, so let's use a different, empirically derived formula that describes the behavior of the system in general."

{| class="wikitable"
|-
! Number !! Explanation
|-
| 18 || Maximum number of electrons in the third (M) {{w|electron shell}}
|-
| 0.1 || 1/10th, a simple decimal
|-
| π || The {{w|Pi|number pi}} ratio of circumference of a circle to half its diameter. Pi is present in many physics equations, often as its double value (2π); also in the definition of the {{w|Planck_constant#Value|reduced Planck constant}} present in quantum-mechanical equations.
|-
| 173 || Could be the mass of the top quark in GeV/c². Or it could be the atomic number from which point {{w|Extended periodic table|supercritical atoms}} (the innermost electron shells of those supercritical atoms have such high binding energies that they {{w|Pair production|create electron-positron pairs from the vaccum}} and thus cannot be fully ionized) start (the latter can be calculated by a mathematical term and does not fit to a typical basic physical theory). Alternatively, a typo, and it should be 137, referring to the fine structure constant which value is approximately 1/137. As an interesting aside the start of the supercritical atoms would be exactly the fine-structure-constant 137, if the nucleus is assumed to have size.
|-
| √2 || An irrational constant, the square root of two, which comes up frequently
|-
| 4i || A simple complex number; i is considered the square root of -1 (4i is the square root of -16)
|}

==Transcript==
{{incomplete transcript|Do NOT delete this tag too soon.}}
:[One large panel with a caption centered on top and ten small drawings in two rows. Each drawing has a description below it.]

:'''Models of the Atom'''
:over time

:[A somewhat imperfectly drawn circle.]
:1810 Small hard ball model

:[A rounded-corners trapezoid inside which there are four small plus signs and four small circles with minus signs inside them.]
:1904 Plum pudding model

:[A bigger circle, with four birds on the surface and music notes above.]
:1907 Tiny bird model

:[A small circle with dots circling around it, drawn with paths.]
:1911 Rutherford model

:[A circle with a plus sign with three circles around it, each with a dot.]
:1913 Bohr model

:[A nunchuck swinging, with the left stick filled with circles with plus signs and the right stick filled with circles with minus signs.]
:1928 Nunchuck model

:[A nucleus with three circles around it, each with a dot.]
:1932 Chadwick model

:[A pie chart, where a part of it has a circle, a part of it has a circle with a minus sign and a part of it has a circle with a plus sign.]
:2008 538 model

:[A small circle with clover-like orbitals around it and surrounded by two outer partly dashed circles.]
:Today Quantum model

:[A circle surrounded with numbers.]
:Numbers: 18, 0.1, π, 173, √2, 4i
:Future "Small hard ball surrounded by math" model

{{comic discussion}}

[[Category:Charts]]
[[Category:Comics featuring real people]] 
[[Category:Physics]]
[[Category:Animals]]

2100: Models of the Atom

2019-01-30T08:36:49Z

172.68.110.46:

{{comic
| number = 2100
| date = January 18, 2019
| title = Models of the Atom
| image = models_of_the_atom.png
| titletext = J.J. Thompson won a Nobel Prize for his work in electricity in gases, but was unfairly passed over for his "An atom is plum pudding, and plum pudding is MADE of atoms! Duuuuude." theory.
}}

==Explanation==
{{incomplete|Created by a COMPLAINING EQUATION. Please mention here why this explanation isn't complete. Do NOT delete this tag too soon.}}

This comic humorously describes the changing view of what an {{w|atom}} is. This has happened so much it seems that we never really knew what we are looking at, and there have been many competing theories aside from the mainstream ones we are taught in school. He lists major depictions in the history of our understanding of an atom, and adds a few humorous ones in to poke fun at how diverse, contentious, and in retrospect often foolhardy, this history has been.

;Small hard ball model
The first model shown, in 1810, is said to be a "small hard ball model." Around this time, {{w|John Dalton}} published his textbook ''A New System of Chemical Philosophy'' which linked existing ideas of atomic theory and chemical reactivity to produce a combined {{w|Law of multiple proportions}} which proposed that each chemical element is comprised of a single unique type of atom, and introduced the concept of {{w|Molecular mass|molecular weight}}. Dalton's theories form the basis of what is known today as {{w|stoichiometry}}, which underpins chemical reactivity. As atoms were considered at this time to be the smallest possible division of matter the scientific community thought of them as "hard round balls" of different sizes; thus the name described here. The "small hard ball" model is still commonly used when teaching and discussing chemical molecules which do not require the level of detail provided by more advanced models, with atoms represented as small, hard, round balls connected by sticks representing chemical bonds.

;Plum pudding model
In the late 19th and early 20th centuries, the study of these "atom" things faced a crisis: where would the newly discovered "{{w|electron}}s" go? In 1904, physicist {{w|J. J. Thomson}}, who discovered electrons, had an idea: maybe the electrons were small point charges moving around in a big mass of positive charge. This was the "{{w|plum pudding model}}", the second model on the comic, called this because people imagined the positively charged mass as a "{{w|Christmas pudding|plum pudding}}". (The title text references Thomson as well, along with the humorous observation that plum puddings themselves are made of atoms.) The problem with this approach is that same charges generally repel, resulting in the more mobile or unbalanced charges forming a surface shell around the others, attempting to escape, rather than being content to being randomly distributed among them.

;Tiny bird model
There were many competing ideas in the formative years of what-are-atoms-made-of-ology, [[Randall]] makes up a 1907 "tiny bird model."

;Rutherford model
Ultimately, the tentative winner in the battle was the model of Thomson's student {{w|Ernest Rutherford}}, who discovered from electrostatic scattering experiments that the positive charge seemed to be concentrated in the center of the atom, and proposed his {{w|Rutherford model}}, or "planetary model", in 1911, where electrons orbit a very concentrated positive charge. This model has often been compared to the orbit of the planets around the sun, with the electrostatic attraction of the electrons and protons shaping the orbits, rather than gravity. This is the fourth model in the comic.

;Bohr model
The Rutherford model could not explain the discrete spectral lines in absorption and emission spectra. It also did not explain why electrons did not spiral in to the nucleus. {{w|Niels Bohr}} patched the model up by proposing that electrons could only exist in distinct "energy levels" at discrete distances from the nucleus. The 1913 "{{w|Bohr model}}", the fifth model shown here, was part of beginning quantum mechanics. Physics behaves differently at the small scale of atoms than the large scales we are more familiar with.

;Nunchuck model
Randall facetiously suggests a "{{w|Nunchaku|nunchuck}} model", the sixth model shown, of a packet of protons swinging a packet of electrons around. One can imagine a handle filled with electrons bonded by the strong nuclear force to a chain made of neutrons, bonded again by the strong nuclear force to a handle made of protons. The heavier protonic handle acts loosely as an orbital center as the electron-filled opposite handle swings wildly around it, attempting to resolve its electrostatic attraction within the restraints of its chain.

;Chadwick model
The next refinement was in the structure of the nucleus. Note that at this time, nobody thought of splitting up the nucleus into {{w|proton}}s and {{w|neutron}}s. But pretty soon people noticed that protons and neutrons existed; {{w|James Chadwick}}, who discovered the neutron, figured that the atom had a nucleus of neutrons and protons, along with a bunch of electrons orbiting around it in a Bohrish manner. This is what the layman today often thinks of as an atom, and is the seventh model shown here.

;538 Model
The eighth model shown is a made up "538 model," in 2008. {{w|FiveThirtyEight|538}} is a statistical analysis website that gained fame in 2008 for predicting every race but 2 correctly in the {{w|2008 United States presidential election|US presidential election}} and predicting every state and Obama's win in the 2012 election. Unlike most other media and polling institutes it saw a rather high probability of 29% for Trump to win the 2016 election by summing up the uncertainties in all the battle states. It has since been known for making mathematical models for everything; the model jokingly suggests that 538 has modeled and presumably made predictions about the atom. The {{w|pie chart}} shows the statistical composition of neutrons, protons and electrons, 38%, 31%, and 31% respectively. This could either be the average of a massive body with several isotopes or represent gallium-69, the most abundant {{w|Isotopes of gallium|isotope of gallium}}, with 31 protons, 31 electrons and 38 neutrons. FiveThirtyEight has previously been mentioned in several xkcd comics, including in [[477: Typewriter]], [[500: Election]], [[635: Locke and Demosthenes]], [[1130: Poll Watching]], [[1779: 2017]], and [[2002: LeBron James and Stephen Curry]]. It's appropriate to list the 538 model as a precursor to the quantum model, as it is a step towards considering the likelihood of different quantities of subatomic particles to be in different volumes of space, rather than considering them as strictly kinematic particles. The comic moves this development into 2008 in support of this joke, when it was actually made much earlier.

;Quantum model
But is the Chadwick model what scientists endorse today? No!
{{w|Maxwell's equations|The theory of electromagnetism}} says that accelerated charges, like the electrons circling, would lose energy emitted as electromagnetic waves and would quickly orbit into the nucleus. Bohr only postulated that this would not happen, but his model could not explain why. Another problem{{Citation needed}} is that atoms, even the hydrogen atom are not flat - which they would be, if a single electron orbited in a circular or elliptical trajectory (the circular motion of charge results in a magnetic moment; Otto Stern and Walter Gerlach {{w|Stern–Gerlach experiment|showed}} that independent from the direction of the measurement the angular momentum - for certain elements - always has the maximum positive or negative value, i.e. not only the radius, but also the angular momentum is quantized - and never zero. You cannot 'look at' the atom from above and 'see' the orbital circle. It always 'seems', as if you 'looked' from the side and would measure the full magnetic dipole. Stern and Gerlach actually saw the spin of an electron of the silver atom instead of the angular momentum, which is according to quantum mechanics 0).
Today (i.e. actually since 1926, 29 years after the discovery of the electron) physicists subscribe to a quantum model, which is the ninth model shown here. Instead of electrons with definite location and momentum (~speed), the parts of the atom are described by probability fields of possible locations and momentums. The changes in momentum probability normally cancel each other out, so there is no electromagnetic radiation. This is very abstract, and in the last model, the model is postulated to get so abstract that it is just a "small hard ball surrounded by math" model, the last model shown. This then is remarkably similar to the model we started out from, the "small hard ball model" (without the math).

;“Small hard ball surrounded by math” model
The picture for the "small ball surrounded by math" depicts a circle with several numbers around it. While the numbers seem to symbolize the "surrounding math" in a general sense, some of them suggest constants used in actual mathematical equations or other numbers related to the quantum model. The shapes and densities of the atomic orbitals are calculated with the {{w|Schrödinger equation}}, which is complex and difficult to solve. Or with string theory, which does not make it easier. For this reason atoms are generally precisely considered in only very simple simulations, and the details of interactions of many atoms at large scales that form our daily lives are incredibly hard to precisely understand and predict on an atomic level. It comes down to "these roundish things we call atoms are moving around in these approximate ways obeying this complex equation with too many numbers involved in most situations to accurately model, so let's use a different, empirically derived formula that describes the behavior of the system in general."

{| class="wikitable"
|-
! Number !! Explanation
|-
| 18 || Maximum number of electrons in the third (M) {{w|electron shell}}
|-
| 0.1 || 1/10th, a simple decimal
|-
| π || The {{w|Pi|number pi}} ratio of circumference of a circle to half its diameter. Pi is present in many physics equations, often as its double value (2π); also in the definition of the {{w|Planck_constant#Value|reduced Planck constant}} present in quantum-mechanical equations.
|-
| 173 || Could be the mass of the top quark in GeV/c². Or it could be the atomic number from which point {{w|Extended periodic table|supercritical atoms}} start (the latter can be calculated by a mathematical term (when starting with the innermost electron shells they have such high binding energies that they {{w|Pair production|create electron-positron pairs from the vaccum}}) and does not fit to a typical basic physical theory). Alternatively, a typo, and it should be 137, referring to the fine structure constant which value is approximately 1/137. As an interesting aside the start of the supercritical atoms would be exactly the fine-structure-constant 137, if the nucleus is assumed to have size.
|-
| √2 || An irrational constant, the square root of two, which comes up frequently
|-
| 4i || A simple complex number; i is considered the square root of -1 (4i is the square root of -16)
|}

==Transcript==
{{incomplete transcript|Do NOT delete this tag too soon.}}
:[One large panel with a caption centered on top and ten small drawings in two rows. Each drawing has a description below it.]

:'''Models of the Atom'''
:over time

:[A somewhat imperfectly drawn circle.]
:1810 Small hard ball model

:[A rounded-corners trapezoid inside which there are four small plus signs and four small circles with minus signs inside them.]
:1904 Plum pudding model

:[A bigger circle, with four birds on the surface and music notes above.]
:1907 Tiny bird model

:[A small circle with dots circling around it, drawn with paths.]
:1911 Rutherford model

:[A circle with a plus sign with three circles around it, each with a dot.]
:1913 Bohr model

:[A nunchuck swinging, with the left stick filled with circles with plus signs and the right stick filled with circles with minus signs.]
:1928 Nunchuck model

:[A nucleus with three circles around it, each with a dot.]
:1932 Chadwick model

:[A pie chart, where a part of it has a circle, a part of it has a circle with a minus sign and a part of it has a circle with a plus sign.]
:2008 538 model

:[A small circle with clover-like orbitals around it and surrounded by two outer partly dashed circles.]
:Today Quantum model

:[A circle surrounded with numbers.]
:Numbers: 18, 0.1, π, 173, √2, 4i
:Future "Small hard ball surrounded by math" model

{{comic discussion}}

[[Category:Charts]]
[[Category:Comics featuring real people]] 
[[Category:Physics]]
[[Category:Animals]]

2100: Models of the Atom

2019-01-30T08:24:44Z

172.68.110.46:

{{comic
| number = 2100
| date = January 18, 2019
| title = Models of the Atom
| image = models_of_the_atom.png
| titletext = J.J. Thompson won a Nobel Prize for his work in electricity in gases, but was unfairly passed over for his "An atom is plum pudding, and plum pudding is MADE of atoms! Duuuuude." theory.
}}

==Explanation==
{{incomplete|Created by a COMPLAINING EQUATION. Please mention here why this explanation isn't complete. Do NOT delete this tag too soon.}}

This comic humorously describes the changing view of what an {{w|atom}} is. This has happened so much it seems that we never really knew what we are looking at, and there have been many competing theories aside from the mainstream ones we are taught in school. He lists major depictions in the history of our understanding of an atom, and adds a few humorous ones in to poke fun at how diverse, contentious, and in retrospect often foolhardy, this history has been.

;Small hard ball model
The first model shown, in 1810, is said to be a "small hard ball model." Around this time, {{w|John Dalton}} published his textbook ''A New System of Chemical Philosophy'' which linked existing ideas of atomic theory and chemical reactivity to produce a combined {{w|Law of multiple proportions}} which proposed that each chemical element is comprised of a single unique type of atom, and introduced the concept of {{w|Molecular mass|molecular weight}}. Dalton's theories form the basis of what is known today as {{w|stoichiometry}}, which underpins chemical reactivity. As atoms were considered at this time to be the smallest possible division of matter the scientific community thought of them as "hard round balls" of different sizes; thus the name described here. The "small hard ball" model is still commonly used when teaching and discussing chemical molecules which do not require the level of detail provided by more advanced models, with atoms represented as small, hard, round balls connected by sticks representing chemical bonds.

;Plum pudding model
In the late 19th and early 20th centuries, the study of these "atom" things faced a crisis: where would the newly discovered "{{w|electron}}s" go? In 1904, physicist {{w|J. J. Thomson}}, who discovered electrons, had an idea: maybe the electrons were small point charges moving around in a big mass of positive charge. This was the "{{w|plum pudding model}}", the second model on the comic, called this because people imagined the positively charged mass as a "{{w|Christmas pudding|plum pudding}}". (The title text references Thomson as well, along with the humorous observation that plum puddings themselves are made of atoms.) The problem with this approach is that same charges generally repel, resulting in the more mobile or unbalanced charges forming a surface shell around the others, attempting to escape, rather than being content to being randomly distributed among them.

;Tiny bird model
There were many competing ideas in the formative years of what-are-atoms-made-of-ology, [[Randall]] makes up a 1907 "tiny bird model."

;Rutherford model
Ultimately, the tentative winner in the battle was the model of Thomson's student {{w|Ernest Rutherford}}, who discovered from electrostatic scattering experiments that the positive charge seemed to be concentrated in the center of the atom, and proposed his {{w|Rutherford model}}, or "planetary model", in 1911, where electrons orbit a very concentrated positive charge. This model has often been compared to the orbit of the planets around the sun, with the electrostatic attraction of the electrons and protons shaping the orbits, rather than gravity. This is the fourth model in the comic.

;Bohr model
The Rutherford model could not explain the discrete spectral lines in absorption and emission spectra. It also did not explain why electrons did not spiral in to the nucleus. {{w|Niels Bohr}} patched the model up by proposing that electrons could only exist in distinct "energy levels" at discrete distances from the nucleus. The 1913 "{{w|Bohr model}}", the fifth model shown here, was part of beginning quantum mechanics. Physics behaves differently at the small scale of atoms than the large scales we are more familiar with.

;Nunchuck model
Randall facetiously suggests a "{{w|Nunchaku|nunchuck}} model", the sixth model shown, of a packet of protons swinging a packet of electrons around. One can imagine a handle filled with electrons bonded by the strong nuclear force to a chain made of neutrons, bonded again by the strong nuclear force to a handle made of protons. The heavier protonic handle acts loosely as an orbital center as the electron-filled opposite handle swings wildly around it, attempting to resolve its electrostatic attraction within the restraints of its chain.

;Chadwick model
The next refinement was in the structure of the nucleus. Note that at this time, nobody thought of splitting up the nucleus into {{w|proton}}s and {{w|neutron}}s. But pretty soon people noticed that protons and neutrons existed; {{w|James Chadwick}}, who discovered the neutron, figured that the atom had a nucleus of neutrons and protons, along with a bunch of electrons orbiting around it in a Bohrish manner. This is what the layman today often thinks of as an atom, and is the seventh model shown here.

;538 Model
The eighth model shown is a made up "538 model," in 2008. {{w|FiveThirtyEight|538}} is a statistical analysis website that gained fame in 2008 for predicting every race but 2 correctly in the {{w|2008 United States presidential election|US presidential election}} and predicting every state and Obama's win in the 2012 election. Unlike most other media and polling institutes it saw a rather high probability of 29% for Trump to win the 2016 election by summing up the uncertainties in all the battle states. It has since been known for making mathematical models for everything; the model jokingly suggests that 538 has modeled and presumably made predictions about the atom. The {{w|pie chart}} shows the statistical composition of neutrons, protons and electrons, 38%, 31%, and 31% respectively. This could either be the average of a massive body with several isotopes or represent gallium-69, the most abundant {{w|Isotopes of gallium|isotope of gallium}}, with 31 protons, 31 electrons and 38 neutrons. FiveThirtyEight has previously been mentioned in several xkcd comics, including in [[477: Typewriter]], [[500: Election]], [[635: Locke and Demosthenes]], [[1130: Poll Watching]], [[1779: 2017]], and [[2002: LeBron James and Stephen Curry]]. It's appropriate to list the 538 model as a precursor to the quantum model, as it is a step towards considering the likelihood of different quantities of subatomic particles to be in different volumes of space, rather than considering them as strictly kinematic particles. The comic moves this development into 2008 in support of this joke, when it was actually made much earlier.

;Quantum model
But is the Chadwick model what scientists endorse today? No!
{{w|Maxwell's equations|The theory of electromagnetism}} says that accelerated charges, like the electrons circling, would lose energy emitted as electromagnetic waves and would quickly orbit into the nucleus. Bohr only postulated that this would not happen, but his model could not explain why. Another problem{{Citation needed}} is that atoms, even the hydrogen atom are not flat - which they would be, if a single electron orbited in a circular or elliptical trajectory (the circular motion of charge results in a magnetic moment; Otto Stern and Walter Gerlach {{w|Stern–Gerlach experiment|showed}} that independent from the direction of the measurement the angular momentum - for certain elements - always has the maximum positive or negative value, i.e. not only the radius, but also the angular momentum is quantized - and never zero. You cannot 'look at' the atom from above and 'see' the orbital circle. It always 'seems', as if you 'looked' from the side and would measure the full magnetic dipole. Stern and Gerlach actually saw the spin of an electron of the silver atom instead of the angular momentum, which is according to quantum mechanics 0).
Today (i.e. actually since 1926, 29 years after the discovery of the electron) physicists subscribe to a quantum model, which is the ninth model shown here. Instead of electrons with definite location and momentum (~speed), the parts of the atom are described by probability fields of possible locations and momentums. The changes in momentum probability normally cancel each other out, so there is no electromagnetic radiation. This is very abstract, and in the last model, the model is postulated to get so abstract that it is just a "small hard ball surrounded by math" model, the last model shown. This then is remarkably similar to the model we started out from, the "small hard ball model" (without the math).

;“Small hard ball surrounded by math” model
The picture for the "small ball surrounded by math" depicts a circle with several numbers around it. While the numbers seem to symbolize the "surrounding math" in a general sense, some of them suggest constants used in actual mathematical equations or other numbers related to the quantum model. The shapes and densities of the atomic orbitals are calculated with the {{w|Schrödinger equation}}, which is complex and difficult to solve. Or with string theory, which does not make it easier. For this reason atoms are generally precisely considered in only very simple simulations, and the details of interactions of many atoms at large scales that form our daily lives are incredibly hard to precisely understand and predict on an atomic level. It comes down to "these roundish things we call atoms are moving around in these approximate ways obeying this complex equation with too many numbers involved in most situations to accurately model, so let's use a different, empirically derived formula that describes the behavior of the system in general."

{| class="wikitable"
|-
! Number !! Explanation
|-
| 18 || Maximum number of electrons in the third (M) {{w|electron shell}}
|-
| 0.1 || 1/10th, a simple decimal
|-
| π || The {{w|Pi|number pi}} ratio of circumference of a circle to half its diameter. Pi is present in many physics equations, often as its double value (2π); also in the definition of the {{w|Planck_constant#Value|reduced Planck constant}} present in quantum-mechanical equations.
|-
| 173 || Possibly a typo (could be 137) referring to the fine structure constant which value is approximately 1/137. Alternatively, 173 could be the mass of the top quark in GeV/c², or it could be the atomic number from which point {{w|Extended periodic table|supercritical atoms}} start.
|-
| √2 || An irrational constant, the square root of two, which comes up frequently
|-
| 4i || A simple complex number; i is considered the square root of -1 (4i is the square root of -16)
|}

==Transcript==
{{incomplete transcript|Do NOT delete this tag too soon.}}
:[One large panel with a caption centered on top and ten small drawings in two rows. Each drawing has a description below it.]

:'''Models of the Atom'''
:over time

:[A somewhat imperfectly drawn circle.]
:1810 Small hard ball model

:[A rounded-corners trapezoid inside which there are four small plus signs and four small circles with minus signs inside them.]
:1904 Plum pudding model

:[A bigger circle, with four birds on the surface and music notes above.]
:1907 Tiny bird model

:[A small circle with dots circling around it, drawn with paths.]
:1911 Rutherford model

:[A circle with a plus sign with three circles around it, each with a dot.]
:1913 Bohr model

:[A nunchuck swinging, with the left stick filled with circles with plus signs and the right stick filled with circles with minus signs.]
:1928 Nunchuck model

:[A nucleus with three circles around it, each with a dot.]
:1932 Chadwick model

:[A pie chart, where a part of it has a circle, a part of it has a circle with a minus sign and a part of it has a circle with a plus sign.]
:2008 538 model

:[A small circle with clover-like orbitals around it and surrounded by two outer partly dashed circles.]
:Today Quantum model

:[A circle surrounded with numbers.]
:Numbers: 18, 0.1, π, 173, √2, 4i
:Future "Small hard ball surrounded by math" model

{{comic discussion}}

[[Category:Charts]]
[[Category:Comics featuring real people]] 
[[Category:Physics]]
[[Category:Animals]]

2100: Models of the Atom

2019-01-30T08:23:50Z

172.68.110.46:

{{comic
| number = 2100
| date = January 18, 2019
| title = Models of the Atom
| image = models_of_the_atom.png
| titletext = J.J. Thompson won a Nobel Prize for his work in electricity in gases, but was unfairly passed over for his "An atom is plum pudding, and plum pudding is MADE of atoms! Duuuuude." theory.
}}

==Explanation==
{{incomplete|Created by a COMPLAINING EQUATION. Please mention here why this explanation isn't complete. Do NOT delete this tag too soon.}}

This comic humorously describes the changing view of what an {{w|atom}} is. This has happened so much it seems that we never really knew what we are looking at, and there have been many competing theories aside from the mainstream ones we are taught in school. He lists major depictions in the history of our understanding of an atom, and adds a few humorous ones in to poke fun at how diverse, contentious, and in retrospect often foolhardy, this history has been.

;Small hard ball model
The first model shown, in 1810, is said to be a "small hard ball model." Around this time, {{w|John Dalton}} published his textbook ''A New System of Chemical Philosophy'' which linked existing ideas of atomic theory and chemical reactivity to produce a combined {{w|Law of multiple proportions}} which proposed that each chemical element is comprised of a single unique type of atom, and introduced the concept of {{w|Molecular mass|molecular weight}}. Dalton's theories form the basis of what is known today as {{w|stoichiometry}}, which underpins chemical reactivity. As atoms were considered at this time to be the smallest possible division of matter the scientific community thought of them as "hard round balls" of different sizes; thus the name described here. The "small hard ball" model is still commonly used when teaching and discussing chemical molecules which do not require the level of detail provided by more advanced models, with atoms represented as small, hard, round balls connected by sticks representing chemical bonds.

;Plum pudding model
In the late 19th and early 20th centuries, the study of these "atom" things faced a crisis: where would the newly discovered "{{w|electron}}s" go? In 1904, physicist {{w|J. J. Thomson}}, who discovered electrons, had an idea: maybe the electrons were small point charges moving around in a big mass of positive charge. This was the "{{w|plum pudding model}}", the second model on the comic, called this because people imagined the positively charged mass as a "{{w|Christmas pudding|plum pudding}}". (The title text references Thomson as well, along with the humorous observation that plum puddings themselves are made of atoms.) The problem with this approach is that same charges generally repel, resulting in the more mobile or unbalanced charges forming a surface shell around the others, attempting to escape, rather than being content to being randomly distributed among them.

;Tiny bird model
There were many competing ideas in the formative years of what-are-atoms-made-of-ology, [[Randall]] makes up a 1907 "tiny bird model."

;Rutherford model
Ultimately, the tentative winner in the battle was the model of Thomson's student {{w|Ernest Rutherford}}, who discovered from electrostatic scattering experiments that the positive charge seemed to be concentrated in the center of the atom, and proposed his {{w|Rutherford model}}, or "planetary model", in 1911, where electrons orbit a very concentrated positive charge. This model has often been compared to the orbit of the planets around the sun, with the electrostatic attraction of the electrons and protons shaping the orbits, rather than gravity. This is the fourth model in the comic.

;Bohr model
The Rutherford model could not explain the discrete spectral lines in absorption and emission spectra. It also did not explain why electrons did not spiral in to the nucleus. {{w|Niels Bohr}} patched the model up by proposing that electrons could only exist in distinct "energy levels" at discrete distances from the nucleus. The 1913 "{{w|Bohr model}}", the fifth model shown here, was part of beginning quantum mechanics. Physics behaves differently at the small scale of atoms than the large scales we are more familiar with.

;Nunchuck model
Randall facetiously suggests a "{{w|Nunchaku|nunchuck}} model", the sixth model shown, of a packet of protons swinging a packet of electrons around. One can imagine a handle filled with electrons bonded by the strong nuclear force to a chain made of neutrons, bonded again by the strong nuclear force to a handle made of protons. The heavier protonic handle acts loosely as an orbital center as the electron-filled opposite handle swings wildly around it, attempting to resolve its electrostatic attraction within the restraints of its chain.

;Chadwick model
The next refinement was in the structure of the nucleus. Note that at this time, nobody thought of splitting up the nucleus into {{w|proton}}s and {{w|neutron}}s. But pretty soon people noticed that protons and neutrons existed; {{w|James Chadwick}}, who discovered the neutron, figured that the atom had a nucleus of neutrons and protons, along with a bunch of electrons orbiting around it in a Bohrish manner. This is what the layman today often thinks of as an atom, and is the seventh model shown here.

;538 Model
The eighth model shown is a made up "538 model," in 2008. {{w|FiveThirtyEight|538}} is a statistical analysis website that gained fame in 2008 for predicting every race but 2 correctly in the {{w|2008 United States presidential election|US presidential election}} and predicting every state and Obama's win in the 2012 election. Unlike most other media and polling institutes it saw a rather high probability of 29% for Trump to win the 2016 election by summing up the uncertainties in all the battle states. It has since been known for making mathematical models for everything; the model jokingly suggests that 538 has modeled and presumably made predictions about the atom. The {{w|pie chart}} shows the statistical composition of neutrons, protons and electrons, 38%, 31%, and 31% respectively. This could either be the average of a massive body with several isotopes or represent gallium-69, the most abundant {{w|Isotopes of gallium|isotope of gallium}}, with 31 protons, 31 electrons and 38 neutrons. FiveThirtyEight has previously been mentioned in several xkcd comics, including in [[477: Typewriter]], [[500: Election]], [[635: Locke and Demosthenes]], [[1130: Poll Watching]], [[1779: 2017]], and [[2002: LeBron James and Stephen Curry]]. It's appropriate to list the 538 model as a precursor to the quantum model, as it is a step towards considering the likelihood of different quantities of subatomic particles to be in different volumes of space, rather than considering them as strictly kinematic particles. The comic moves this development into 2008 in support of this joke, when it was actually made much earlier.

;Quantum model
But is the Chadwick model what scientists endorse today? No!
{{w|Maxwell's equations|The theory of electromagnetism}} says that accelerated charges, like the electrons circling, would lose energy emitted as electromagnetic waves and would quickly orbit into the nucleus. Bohr only postulated that this would not happen, but his model could not explain why. Another problem{{Citation needed}} is that atoms, even the hydrogen atom are not flat - which they would be, if a single electron orbited in a circular or elliptical trajectory (the circular motion of charge results in a magnetic moment; Otto Stern and Walter Gerlach {{w|Stern–Gerlach experiment|showed}} that independent from the direction of the measurement the angular momentum - for certain elements - always has the maximum positive or negative value, i.e. not only the radius, but also the angular momentum is quantized - and never zero. You cannot 'look at' the atom from above and 'see' the orbital circle. It always 'seems', as if you 'looked' from the side and would measure the full magnetic dipole. Stern and Gerlach actually saw the spin of an electron of the silver atom instead of the angular momentum, which is according to quantum mechanics 0).
Today (i.e. actually since 1926, 29 years after the discovery of the electron) physicists subscribe to a quantum model, which is the ninth model shown here. Instead of electrons with definite location and momentum (~speed), the parts of the atom are described by probability fields of possible locations and momentums. The changes in momentum probability normally cancel each other out, so there is no electromagnetic radiation. This is very abstract, and in the last model, the model is postulated to get so abstract that it is just a "small hard ball surrounded by math" model, the last model shown. This then is remarkably similar to the model we started out from, the "small hard ball model" (without the math).

;“Small hard ball surrounded by math” model
The picture for the "small ball surrounded by math" depicts a circle with several numbers around it. While the numbers seem to symbolize the "surrounding math" in a general sense, some of them suggest constants used in actual mathematical equations or other numbers related to the quantum model. The shapes and densities of the atomic orbitals are calculated with the {{w|Schrödinger equation}}, which is complex and difficult to solve. Or with string theory, which does not make it easier. For this reason atoms are generally precisely considered in only very simple simulations, and the details of interactions of many atoms at large scales that form our daily lives are incredibly hard to precisely understand and predict on an atomic level. It comes down to "these roundish things we call atoms are moving around in these approximate ways obeying this complex equation with too many numbers involved in most situations to accurately model, so let's use a different, empirically derived formula that describes the behavior of the system in general."

{| class="wikitable"
|-
! Number !! Explanation
|-
| 18 || Maximum number of electrons in the third (M) {{w|electron shell}}
|-
| 0.1 || 1/10th, a simple decimal
|-
| π || The {{w|Pi|number pi}} ratio of circumference of a circle to half its diameter. Pi is present in many physics equations, often as its double value (2π); also in the definition of the {{w|Planck_constant#Value|reduced Planck constant}} present in quantum-mechanical equations.
|-
| 173 || Possibly a typo (could be 137) referring to the fine structure constant which value is approximately 1/137. 173 could be the mass of the top quark in GeV/c² or the atomic number from which point {{w|Extended periodic table|supercritical atoms}} start.
|-
| √2 || An irrational constant, the square root of two, which comes up frequently
|-
| 4i || A simple complex number; i is considered the square root of -1 (4i is the square root of -16)
|}

==Transcript==
{{incomplete transcript|Do NOT delete this tag too soon.}}
:[One large panel with a caption centered on top and ten small drawings in two rows. Each drawing has a description below it.]

:'''Models of the Atom'''
:over time

:[A somewhat imperfectly drawn circle.]
:1810 Small hard ball model

:[A rounded-corners trapezoid inside which there are four small plus signs and four small circles with minus signs inside them.]
:1904 Plum pudding model

:[A bigger circle, with four birds on the surface and music notes above.]
:1907 Tiny bird model

:[A small circle with dots circling around it, drawn with paths.]
:1911 Rutherford model

:[A circle with a plus sign with three circles around it, each with a dot.]
:1913 Bohr model

:[A nunchuck swinging, with the left stick filled with circles with plus signs and the right stick filled with circles with minus signs.]
:1928 Nunchuck model

:[A nucleus with three circles around it, each with a dot.]
:1932 Chadwick model

:[A pie chart, where a part of it has a circle, a part of it has a circle with a minus sign and a part of it has a circle with a plus sign.]
:2008 538 model

:[A small circle with clover-like orbitals around it and surrounded by two outer partly dashed circles.]
:Today Quantum model

:[A circle surrounded with numbers.]
:Numbers: 18, 0.1, π, 173, √2, 4i
:Future "Small hard ball surrounded by math" model

{{comic discussion}}

[[Category:Charts]]
[[Category:Comics featuring real people]] 
[[Category:Physics]]
[[Category:Animals]]

Talk:2105: Modern OSI Model

2019-01-30T08:17:24Z

172.68.110.46:

Randall seems to be saying that a startup doesn't need to create a new computer system to service their customers, all they have to do is put up a Facebook page which uses Google to find products and then has Amazon deliver them. The middle layer "Transport" is a joke because Amazon literally ships physical boxes, but the OSI model is not about actual boxes; it's about information and the way the information is presented to the user vs what goes on behind the scenes.
But I don't get the part about the horcruxes. Is it just the fact that there are seven of them? Or is there some subtle connection I'm missing here? [[Special:Contributions/162.158.106.180|162.158.106.180]] 05:50, 30 January 2019 (UTC)
:(Spoilers alert) Voldemort uses signifying objects of his life, heritage and his school's founders as horcruces. When the OSI layers are used as horcruces, one problem would be that Google/Amazon would have taken control of two horcruces, the other that some of the layers are frayed at the sides. Randall should not have put his horcruces in living standards - that was a very dangerous move. Sebastian --[[Special:Contributions/172.68.110.46|172.68.110.46]] 07:54, 30 January 2019 (UTC)

Is there a meaning of the widths of the layers - not a block or a triangle/pyramid? Are there more layers than the named ones? Or the named ones multiple times? This would correspond to the design of ever more layers, virtualizations, abstractions and overall complexity of computer systems as time moved forward. Sebastian --[[Special:Contributions/172.68.110.46|172.68.110.46]] 07:49, 30 January 2019 (UTC)

I think Google & Amazon are the grey blob that is slowly absorbing all of the layers [[Special:Contributions/141.101.107.114|141.101.107.114]] 07:55, 30 January 2019 (UTC)

Trivia: (Major Spoiler alert) Voldemort originally intended to create six horcruces to divide his soul into 7 (including his own body) pieces. The 6th unintended horcrux is Harry Potter by Voldemort killing his parents. Later on after his revival Voldemort made the snake Nagini to his seemingly 6th horcrux, which was actually his 7th. Does that mean Randall embodies one of the OSI layers from the beginning of his existence? :-) Sebastian --[[Special:Contributions/172.68.110.46|172.68.110.46]] 08:01, 30 January 2019 (UTC)

Talk:2105: Modern OSI Model

2019-01-30T08:14:34Z

172.68.110.46:

Randall seems to be saying that a startup doesn't need to create a new computer system to service their customers, all they have to do is put up a Facebook page which uses Google to find products and then has Amazon deliver them. The middle layer "Transport" is a joke because Amazon literally ships physical boxes, but the OSI model is not about actual boxes; it's about information and the way the information is presented to the user vs what goes on behind the scenes.
But I don't get the part about the horcruxes. Is it just the fact that there are seven of them? Or is there some subtle connection I'm missing here? [[Special:Contributions/162.158.106.180|162.158.106.180]] 05:50, 30 January 2019 (UTC)
:(Spoilers alert) Voldemort uses signifying objects of his life, heritage and his school's founders as horcruces. When the OSI layers are used as horcruces, one problem would be that Google/Amazon would have taken control of two horcruces, the other that some of the layers are frayed at the sides. Randall should not have put his horcruces in living standards - that was a very dangerous move. Sebastian --[[Special:Contributions/172.68.110.46|172.68.110.46]] 07:54, 30 January 2019 (UTC)

Is there a meaning of the widths of the layers - not a block or a triangle/pyramid? Are there more layers than the named ones? Or the named ones multiple times? This would correspond to the design of ever more layers, virtualizations, abstractions and overall complexity of computer systems as time moved forward. Sebastian --[[Special:Contributions/172.68.110.46|172.68.110.46]] 07:49, 30 January 2019 (UTC)

I think Google & Amazon are the grey blob that is slowly absorbing all of the layers [[Special:Contributions/141.101.107.114|141.101.107.114]] 07:55, 30 January 2019 (UTC)

Trivia: (Major Spoiler alert) Voldemort originally intended to create six horcruces to divide his soul into 7 (including his own body) pieces. The 7th horcrux is Harry Potter by Voldemort killing his parents. Does that mean Randall embodies one of the OSI layers from the beginning of his existence? :-) Sebastian --[[Special:Contributions/172.68.110.46|172.68.110.46]] 08:01, 30 January 2019 (UTC)

Talk:2105: Modern OSI Model

2019-01-30T08:01:41Z

172.68.110.46:

Randall seems to be saying that a startup doesn't need to create a new computer system to service their customers, all they have to do is put up a Facebook page which uses Google to find products and then has Amazon deliver them. The middle layer "Transport" is a joke because Amazon literally ships physical boxes, but the OSI model is not about actual boxes; it's about information and the way the information is presented to the user vs what goes on behind the scenes.
But I don't get the part about the horcruxes. Is it just the fact that there are seven of them? Or is there some subtle connection I'm missing here? [[Special:Contributions/162.158.106.180|162.158.106.180]] 05:50, 30 January 2019 (UTC)
:(Spoilers alert) Voldemort uses signifying objects of his life, heritage and his school's founders as horcruces. When the OSI layers are used as horcruces, one problem would be that Google/Amazon would have taken control of two horcruces, the other that some of the layers are frayed at the sides. Randall should not have put his horcruces in living standards - that was a very dangerous move. Sebastian --[[Special:Contributions/172.68.110.46|172.68.110.46]] 07:54, 30 January 2019 (UTC)

Is there a meaning of the widths of the layers - not a block or a triangle/pyramid? Are there more layers than the named ones? Or the named ones multiple times? This would correspond to the design of ever more layers, virtualizations, abstractions and overall complexity of computer systems as time moved forward. Sebastian --[[Special:Contributions/172.68.110.46|172.68.110.46]] 07:49, 30 January 2019 (UTC)

I think Google & Amazon are the grey blob that is slowly absorbing all of the layers [[Special:Contributions/141.101.107.114|141.101.107.114]] 07:55, 30 January 2019 (UTC)

Trivia: (Major Spoiler alert) Voldemort intended to create six horcruces to divide his soul into 7 (including his own body) pieces. The 7th horcrux is Harry Potter by Voldemort killing his parents. Does that mean Randall embodies one of the OSI layers from the beginning of his existence? :-) Sebastian --[[Special:Contributions/172.68.110.46|172.68.110.46]] 08:01, 30 January 2019 (UTC)

Talk:2105: Modern OSI Model

2019-01-30T07:57:36Z

172.68.110.46:

Talk:2105: Modern OSI Model

2019-01-30T07:57:03Z

172.68.110.46:

Randall seems to be saying that a startup doesn't need to create a new computer system to service their customers, all they have to do is put up a Facebook page which uses Google to find products and then has Amazon deliver them. The middle layer "Transport" is a joke because Amazon literally ships physical boxes, but the OSI model is not about actual boxes; it's about information and the way the information is presented to the user vs what goes on behind the scenes.
But I don't get the part about the horcruxes. Is it just the fact that there are seven of them? Or is there some subtle connection I'm missing here? [[Special:Contributions/162.158.106.180|162.158.106.180]] 05:50, 30 January 2019 (UTC)
:(Spoilers alert) Voldemort uses signifying objects of his life, heritage and his school's founders as horcruces. When the OSI layers are used as horcruces, one problem would be that Google/Amazon would have taken control of two horcruces, the other that some of the layers are frayed at the sides. Randall should have put his horcruces in living standards - that was a very dangerous move. Sebastian --[[Special:Contributions/172.68.110.46|172.68.110.46]] 07:54, 30 January 2019 (UTC)

Is there a meaning of the widths of the layers - not a block or a triangle/pyramid? Are there more layers than the named ones? Or the named ones multiple times? This would correspond to the design of ever more layers, virtualizations, abstractions and overall complexity of computer systems as time moved forward. Sebastian --[[Special:Contributions/172.68.110.46|172.68.110.46]] 07:49, 30 January 2019 (UTC)

I think Google & Amazon are the grey blob that is slowly absorbing all of the layers [[Special:Contributions/141.101.107.114|141.101.107.114]] 07:55, 30 January 2019 (UTC)

Talk:2105: Modern OSI Model

2019-01-30T07:56:37Z

172.68.110.46:

Randall seems to be saying that a startup doesn't need to create a new computer system to service their customers, all they have to do is put up a Facebook page which uses Google to find products and then has Amazon deliver them. The middle layer "Transport" is a joke because Amazon literally ships physical boxes, but the OSI model is not about actual boxes; it's about information and the way the information is presented to the user vs what goes on behind the scenes.
But I don't get the part about the horcruxes. Is it just the fact that there are seven of them? Or is there some subtle connection I'm missing here? [[Special:Contributions/162.158.106.180|162.158.106.180]] 05:50, 30 January 2019 (UTC)
:(Spoilers alert) Voldemort uses signifying objects of his life, heritage and his school's founders as horcruxes. When the OSI layers are used as horcruces, one problem would be that Google/Amazon would have taken control of two horcruces, the other that some of the layers are frayed at the sides. Randall should have put his horcruces in living standards - that was a very dangerous move. Sebastian --[[Special:Contributions/172.68.110.46|172.68.110.46]] 07:54, 30 January 2019 (UTC)

Is there a meaning of the widths of the layers - not a block or a triangle/pyramid? Are there more layers than the named ones? Or the named ones multiple times? This would correspond to the design of ever more layers, virtualizations, abstractions and overall complexity of computer systems as time moved forward. Sebastian --[[Special:Contributions/172.68.110.46|172.68.110.46]] 07:49, 30 January 2019 (UTC)

I think Google & Amazon are the grey blob that is slowly absorbing all of the layers [[Special:Contributions/141.101.107.114|141.101.107.114]] 07:55, 30 January 2019 (UTC)

Talk:2105: Modern OSI Model

2019-01-30T07:54:58Z

172.68.110.46:

Talk:2105: Modern OSI Model

2019-01-30T07:49:47Z

172.68.110.46:

2100: Models of the Atom

2019-01-23T19:31:30Z

172.68.110.46:

{{comic
| number = 2100
| date = January 18, 2019
| title = Models of the Atom
| image = models_of_the_atom.png
| titletext = J.J. Thompson won a Nobel Prize for his work in electricity in gases, but was unfairly passed over for his "An atom is plum pudding, and plum pudding is MADE of atoms! Duuuuude." theory.
}}

==Explanation==
{{incomplete|Created by a COMPLAINING EQUATION. Please mention here why this explanation isn't complete. Do NOT delete this tag too soon.}}

This comic humorously describes the changing view of what an {{w|atom}} is. This has happened so much it seems that we never really knew what we are looking at, and there have been many competing theories aside from the mainstream ones we are taught in school. He lists major depictions in the history of our understanding of an atom, and adds a few humorous ones in to poke fun at how diverse, contentious, and in retrospect often foolhardy, this history has been.

;Small hard ball model
The first model shown, in 1810, is said to be a "small hard ball model." Around this time, {{w|John Dalton}} published his textbook ''A New System of Chemical Philosophy'' which linked existing ideas of atomic theory and chemical reactivity to produce a combined {{w|Law of multiple proportions}} which proposed that each chemical element is comprised of a single unique type of atom, and introduced the concept of {{w|Molecular mass|molecular weight}}. Dalton's theories form the basis of what is known today as {{w|stoichiometry}}, which underpins chemical reactivity. As atoms were considered at this time to be the smallest possible division of matter the scientific community thought of them as "hard round balls" of different sizes; thus the name described here. The "small hard ball" model is still commonly used when teaching and discussing chemical molecules which do not require the level of detail provided by more advanced models, with atoms represented as small, hard, round balls connected by sticks representing chemical bonds.

;Plum pudding model
In the late 19th and early 20th centuries, the study of these "atom" things faced a crisis: where would the newly discovered "{{w|electron}}s" go? In 1904, physicist {{w|J. J. Thomson}}, who discovered electrons, had an idea: maybe the electrons were small point charges moving around in a big mass of positive charge. This was the "{{w|plum pudding model}}", the second model on the comic, called this because people imagined the positively charged mass as a "{{w|Christmas pudding|plum pudding}}". (The title text references Thomson as well, along with the humorous observation that plum puddings themselves are made of atoms.) The problem with this approach is that same charges generally repel, resulting in the more mobile or unbalanced charges forming a surface shell around the others, attempting to escape, rather than being content to being randomly distributed among them.

;Tiny bird model
There were many competing ideas in the formative years of what-are-atoms-made-of-ology, [[Randall]] makes up a 1907 "tiny bird model."

;Rutherford model
Ultimately, the tentative winner in the battle was the model of Thomson's student {{w|Ernest Rutherford}}, who discovered from electrostatic scattering experiments that the positive charge seemed to be concentrated in the center of the atom, and proposed his {{w|Rutherford model}}, or "planetary model", in 1911, where electrons orbit a very concentrated positive charge. This model has often been compared to the orbit of the planets around the sun, with the electrostatic attraction of the electrons and protons shaping the orbits, rather than gravity. This is the fourth model in the comic.

;Bohr model
The Rutherford model could not explain the discrete spectral lines in absorption and emission spectra. It also did not explain why electrons did not spiral in to the nucleus. {{w|Niels Bohr}} patched the model up by proposing that electrons could only exist in distinct "energy levels" at discrete distances from the nucleus. The 1913 "{{w|Bohr model}}", the fifth model shown here, was part of beginning quantum mechanics. Physics behaves differently at the small scale of atoms than the large scales we are more familiar with.

;Nunchuck model
Randall facetiously suggests a "{{w|Nunchaku|nunchuck}} model", the sixth model shown, of a packet of protons swinging a packet of electrons around. One can imagine a handle filled with electrons bonded by the strong nuclear force to a chain made of neutrons, bonded again by the strong nuclear force to a handle made of protons. The heavier protonic handle acts loosely as an orbital center as the electron-filled opposite handle swings wildly around it, attempting to resolve its electrostatic attraction within the restraints of its chain.

;Chadwick model
The next refinement was in the structure of the nucleus. Note that at this time, nobody thought of splitting up the nucleus into {{w|proton}}s and {{w|neutron}}s. But pretty soon people noticed that protons and neutrons existed; {{w|James Chadwick}}, who discovered the neutron, figured that the atom had a nucleus of neutrons and protons, along with a bunch of electrons orbiting around it in a Bohrish manner. This is what the layman today often thinks of as an atom, and is the seventh model shown here.

;538 Model
The eighth model shown is a made up "538 model," in 2008. {{w|FiveThirtyEight|538}} is a statistical analysis website that gained fame in 2008 for predicting every race but 2 correctly in the {{w|2008 United States presidential election|US presidential election}} and predicting every state and Obama's win in the 2012 election. Unlike most other media and polling institutes it saw a rather high probability of 29% for Trump to win the 2016 election by summing up the uncertainties in all the battle states. It has since been known for making mathematical models for everything; the model jokingly suggests that 538 has modeled and presumably made predictions about the atom. The {{w|pie chart}} shows the statistical composition of neutrons, protons and electrons, 38%, 31%, and 31% respectively. This could either be the average of a massive body with several isotopes or represent gallium-69, the most abundant {{w|Isotopes of gallium|isotope of gallium}}, with 31 protons, 31 electrons and 38 neutrons. FiveThirtyEight has previously been mentioned in several xkcd comics, including in [[477: Typewriter]], [[500: Election]], [[635: Locke and Demosthenes]], [[1130: Poll Watching]], [[1779: 2017]], and [[2002: LeBron James and Stephen Curry]]. It's appropriate to list the 538 model as a precursor to the quantum model, as it is a step towards considering the likelihood of different quantities of subatomic particles to be in different volumes of space, rather than considering them as strictly kinematic particles. The comic moves this development into 2008 in support of this joke, when it was actually made much earlier.

;Quantum model
But is the Chadwick model what scientists endorse today? No!
{{w|Maxwell's equations|The theory of electromagnetism}} says that accelerated charges, like the electrons circling, would lose energy emitted as electromagnetic waves and would quickly orbit into the nucleus. Bohr only postulated that this would not happen, but his model could not explain why. Another problem{{Citation needed}} is that atoms, even the hydrogen atom are not flat - which they would be, if a single electron orbited in a circular or elliptical trajectory (the circular motion of charge results in a magnetic moment; Otto Stern and Walter Gerlach {{w|Stern–Gerlach experiment|showed}} that independent from the direction of the measurement the angular momentum always has the maximum positive or negative value, i.e. not only the radius, but also the angular momentum is quantized - and never zero. You cannot 'look at' the atom from above and 'see' the orbital circle. It always 'seems', as if you 'looked' from the side and would measure the full magnetic dipole. Stern and Gerlach actually saw the spin of an electron of the silver atom instead of the angular momentum, which is according to quantum mechanics 0).
Today (i.e. actually since 1926, 29 years after the discovery of the electron) physicists subscribe to a quantum model, which is the ninth model shown here. Instead of electrons with definite location and momentum (~speed), the parts of the atom are described by probability fields of possible locations and momentums. The changes in momentum probability normally cancel each other out, so there is no electromagnetic radiation. This is very abstract, and in the last model, the model is postulated to get so abstract that it is just a "small hard ball surrounded by math" model, the last model shown. This then is remarkably similar to the model we started out from, the "small hard ball model" (without the math).

;“Small hard ball surrounded by math” model
The picture for the "small ball surrounded by math" depicts a circle with several numbers around it. While the numbers seem to symbolize the "surrounding math" in a general sense, some of them suggest constants used in actual mathematical equations or other numbers related to the quantum model. The shapes and densities of the atomic orbitals are calculated with the {{w|Schrödinger equation}}, which is complex and difficult to solve. Or with string theory, which does not make it easier. For this reason atoms are generally precisely considered in only very simple simulations, and the details of interactions of many atoms at large scales that form our daily lives are incredibly hard to precisely understand and predict on an atomic level. It comes down to "these roundish things we call atoms are moving around in these approximate ways obeying this complex equation with too many numbers involved in most situations to accurately model, so let's use a different, empirically derived formula that describes the behavior of the system in general."

{| class="wikitable"
|-
! Number !! Explanation
|-
| 18 || Maximum number of electrons in the third (M) {{w|electron shell}}
|-
| 0.1 || 1/10th, a simple decimal
|-
| π || The {{w|Pi|number pi}} ratio of circumference of a circle to half its diameter. Pi is present in many physics equations, often as its double value (2π); also in the definition of the {{w|Planck_constant#Value|reduced Planck constant}} present in quantum-mechanical equations.
|-
| 173 || Possibly a typo (could be 137) referring to the fine structure constant which value is approximately 1/137
|-
| √2 || An irrational constant, the square root of two, which comes up frequently
|-
| 4i || A simple complex number; i is considered the square root of -1 (4i is the square root of -16)
|}

==Transcript==
{{incomplete transcript|Do NOT delete this tag too soon.}}
:[One large panel with a caption centered on top and ten small drawings in two rows. Each drawing has a description below it.]

:'''Models of the Atom'''
:over time

:[A somewhat imperfectly drawn circle.]
:1810 Small hard ball model

:[A rounded-corners trapezoid inside which there are four small plus signs and four small circles with minus signs inside them.]
:1904 Plum pudding model

:[A bigger circle, with four birds on the surface and music notes above.]
:1907 Tiny bird model

:[A small circle with dots circling around it, drawn with paths.]
:1911 Rutherford model

:[A circle with a plus sign with three circles around it, each with a dot.]
:1913 Bohr model

:[A nunchuck swinging, with the left stick filled with circles with plus signs and the right stick filled with circles with minus signs.]
:1928 Nunchuck model

:[A nucleus with three circles around it, each with a dot.]
:1932 Chadwick model

:[A pie chart, where a part of it has a circle, a part of it has a circle with a minus sign and a part of it has a circle with a plus sign.]
:2008 538 model

:[A small circle with clover-like orbitals around it and surrounded by two outer partly dashed circles.]
:Today Quantum model

:[A circle surrounded with numbers.]
:Numbers: 18, 0.1, π, 173, √2, 4i
:Future "Small hard ball surrounded by math" model

{{comic discussion}}

[[Category:Charts]]
[[Category:Comics featuring real people]] 
[[Category:Physics]]
[[Category:Animals]]

Talk:2100: Models of the Atom

2019-01-18T15:16:04Z

172.68.110.46:

No mention of the Platonic solid model? [[User:DanielLC|DanielLC]] ([[User talk:DanielLC|talk]]) 05:56, 18 January 2019 (UTC)

Not yet. My favorite of those 5 is the double cube, AKA the Octahedron. [[User:Haph|Haph]] ([[User talk:Haph|talk]]) 06:35, 18 January 2019 (UTC)

:My good sir DanielLC: I presume that Randall neglected to mention it because the first evidence-based atom theory didn't come until 1810 and John Dalton. The atom theories of the ancient Greeks were mostly philosophical posturing, in my opinion.

:We seem to be missing the [[https://en.wikipedia.org/wiki/Acorn_Atom| Acorm Atom]] as well. [[User:Kazzie|Kazzie]] ([[User talk:Kazzie|talk]]) 10:16, 18 January 2019 (UTC)

According to [[https://www.ast.cam.ac.uk/~trentham/cosmology/lec6.pdf|cosmology lecture notes by the astronomer Neil Trentham]], mass in the universe ist 75% H (mostly 1p+0n=1) and 25% He (mostly 2p+2n=4). As He is 4 times as heavy and 3 times as seldom, there is 12 times more H than He => The ratio n/p is 1/7.
We can assume that in the 538 model the statistics was done on atoms comprising few Hydrogene, e.g. only the earth's mantle. In heavier elements the ratio n/p > 1. Sebastian --[[Special:Contributions/172.68.110.70|172.68.110.70]] 07:39, 18 January 2019 (UTC)

What are the numbers? Is 173 an error for 137, the fine structure constant? [[User:Sabik|Sabik]] ([[User talk:Sabik|talk]]) 10:36, 18 January 2019 (UTC)
: It reminds me of the mass of the top quark (<s>even though the current best value is 172.44 GeV</s>, 173, as measured at the time at Tevatron, was used as a good approximation for a long time. The latest Particle Data Group review also gives something rounding to 173) [[Special:Contributions/141.101.107.174|141.101.107.174]] 13:55, 18 January 2019 (UTC)
:Do they really need a table for explanation? wouldn't a simple list be much easier to read? in my POV (which AFAIK is shared by many here) a table with just 2 columns is not useful at all --[[User:Lupo|Lupo]] ([[User talk:Lupo|talk]]) 14:17, 18 January 2019 (UTC)

The tiny bird model puzzles me completely. Is it a reference to any interim (even if obscure) scientific model or is it a completely facetious Randall's invention? Or is it a reference to something unrelated? Any ideas? -- [[Special:Contributions/162.158.92.34|162.158.92.34]] 12:55, 18 January 2019 (UTC)

The absolute scale of physical constants seldom has specific meaning. See h vs ħ (h bar). Neither is right or wrong and they can be used interchangeably (when putting the 2*pi in or removing it at the same time). The same is true for dimensionless constants. E.g. 4*pi *(h bar) = 2 *(h). So the 4*pi as dimensionless constant is as correct as 2 or any other dimensionless number, as you can rescale other constants. If you redefine some natural constants, the value 137 also changes. Most dimensionless constants can be deduced from mathematics with a known or yet unknown underlying physical theory. For example all chemical properties of elements (=chemical constants) can be calculated from the underlying physics by very complex mathematical terms. For an excursion that also mathematical constants are open for debate, see the [[1292: Pi vs. Tau|Pi vs Tau]] debate. Both are correct. Sebastian --[[Special:Contributions/172.68.110.46|172.68.110.46]] 15:16, 18 January 2019 (UTC)

2100: Models of the Atom

2019-01-18T14:54:11Z

172.68.110.46:

2100: Models of the Atom

2019-01-18T14:51:20Z

172.68.110.46:

977: Map Projections

2018-03-20T22:53:44Z

172.68.110.46: /* Dymaxion */ updated information on 3D goggles

{{comic
| number = 977
| date = November 14, 2011
| title = Map Projections
| before = [[#Explanation|↓ Skip to explanation ↓]]
| image = map_projections.png
| titletext = What's that? You think I don't like the Peters map because I'm uncomfortable with having my cultural assumptions challenged? Are you sure you're not... ::puts on sunglasses:: ...projecting?
}}
__TOC__
==Explanation==
{{w|Map projection}}, or how to represent the spherical Earth surface onto a flat support (paper, screen...) to have a usable map, is a long-time issue with very practical aspects (navigation, geographical shapes and masses visualization, etc.) as well as very scientific/mathematical ones, involving geometry or even abstract algebra among other things. There is no universal solution to this problem: Any 2D map projection will always distort in a way the spherical reality. Many projections have been proposed in various contexts, each intending to minimize distortions for specific uses (for nautical navigation, for aerial navigation, for landmass size comparisons, etc.) but having drawbacks from other points of view. Some of them are more frequently used than others in mass media and therefore more well-known than others, some are purely historical and now deprecated, some are very obscure, etc.

[[Randall]] suggests here the idea that someone's "favorite" map projection can reveal aspects of their personality, then goes through a series of them to show what they can mean.

He may actually believe that all map projections are in a way bad. This could be inferred from the fact that he much later began publishing a series of [[:Category:Bad Map Projections|Bad Map Projections]], starting with [[1784: Bad Map Projection: Liquid Resize]], which was Bad Map Projection #107 on his list, and was followed up by #79: [[1799: Bad Map Projection: Time Zones]]. The projections below could be #1-#12 on that list, although the last one, where Randall hates those that love it, might be somewhat further down the list.

===Mercator===
[[File:MercatorProjection.jpg|frame|The Mercator projection]]
The {{w|Mercator projection}} was introduced by Flemish cartographer Gerardus Mercator in 1569. The main purpose of this map is to preserve compass bearings; for example 13 degrees east of north will be 13 degrees clockwise from the ray pointing toward the top of the map, at every point. A mathematical consequence is the mapping is conformal, i.e. if two roads meet at a certain angle on the surface of the Earth, they will meet at that same angle on the map. It also follows that at every point the vertical and horizontal scales are the same, so locally i.e. considering only a small part of the map, geographical features (shapes, angles) are well represented, which helps a lot in recognizing them on-the-field, or for local navigation in that small part only. For this reason, that projection (or a close variant) is used in several online mapping services, such as Google Maps, which means that it is frequently encountered by the general public. A straight line on the map corresponds to a course of constant bearing (direction), which was very useful for nautical navigation in the past (and thus made that projection very well-known).

However, from a global point of view, this projection is radically incorrect in how it shows the size of landmasses (for instance, Antarctica and Greenland seem gigantic), and furthermore, it always excludes a small region around each pole (otherwise the map would be of infinite height), so it doesn't provide a complete solution for the problem of map projection. The comic implies that people who like that projection aren't very interested with map issues, and typically use what they are offered without thinking much about it.

{{clear}}

===Van der Grinten===
[[File:VanDerGrintenProjection.jpg|frame|The Van der Grinten projection]]
The {{w|Van der Grinten projection}} is not much better than the Mercator. It was adopted by {{w|National Geographic}} in 1922 and was used until they updated to the Robinson projection in 1988.

The Van der Grinten projection is circular as opposed to the Mercator projection. The fictional person believes a circular map is more fitting to the real Earth's three-dimensional spherical nature because both are round. This belief fails to recognize that a two-dimensional circle has very little in common with the surface of a sphere, and thus this projection still causes a vast distortion of space and area. Because of this, Randall implies the Van der Grinten enthusiast to be optimistic and childishly simple-minded (e.g. "you like circles").

{{clear}}

===Robinson===
[[File:RobinsonProjection.jpg|frame|The Robinson projection]]
The {{w|Robinson projection}} was developed by {{w|Arthur H. Robinson}} as a map that was supposed to look nice and is often used for classroom maps. National Geographic switched to this projection in 1988, and used it for ten years, switching to the Winkel-Tripel in 1998.

{{w|The Beatles}} was a rock band that enjoyed great commercial success in the 1960s, and are widely considered the best act ever in the genre of popular music. The Beatles, coffee, and running shoes are all things that are very commonly enjoyed and largely uncontroversial, as well as being comforting. Liking these specific things suggests an ordinary, easygoing lifestyle paralleled by the projection.

{{clear}}

===Dymaxion===
[[File:DymaxionProjection.jpg|frame|The Dymaxion projection]]
Also called the Fuller Map, the {{w|Dymaxion map}} takes a sphere and projects it onto an icosahedron, that is a polyhedron with 20 triangular faces. It is far easier to unwrap an icosahedron than it is to unwrap a sphere into a 2D object and has very little skewing of the poles. {{w|Buckminster Fuller}} was an eccentric futurist who believed, for example, that world maps should allow no conception of "up" or "down". He was therefore more than happy to defy people's expectations about maps in the pursuit of mathematical accuracy.

Randall associates the projection to geek subculture and niche markets:
*{{w|Isaac Asimov}} was an American science-fiction writer, who (as well as publishing many textbooks) is considered the father of the modern concept of robots. He invented the {{w|Three Laws of Robotics}}. He also worked on more than 500 books throughout his career.
*{{w|XML}} is the eXtensible Markup Language. It is used to represent data in a format that machines can read and understand, as well as being human-readable. In practice, XML is cumbersome to read.
*{{w|Vibram FiveFingers|Toed shoes}} are a [[1065: Shoes|favorite]] of Randall's to pick on. In society they are seen as a {{w|geek}} clothing item.
*Brought to the world by {{w|Dean Kamen}}, the {{w|Segway PT}} was supposed to be a device that changed the way cities were built. In reality, most principalities have put in place rules specifically against Segways, making them a frustration to own and use within the law (in some states in Australia, it is illegal to use them on public footpaths or roads). Also, the former owner of {{w|Segway Inc.}}, the late {{w|Jimi Heselden}}, accidentally rode his Segway off a cliff in 2010.
*At the time of comic release, 3D goggles, nowadays widely known as {{w|Virtual reality headset|VR headsets}}, were considered a gimmick at best. The original idea is as old as 3D graphics, but it never really took off until mid-2010s. Earlier products were very unwieldy and offered poor graphics quality, so no one took this technology seriously.
*{{w|Dvorak Simplified Keyboard|Dvorak}} is an alternate keyboard layout to {{w|QWERTY}}. According to legend, QWERTY was invented to help keep manual typewriters from jamming (by placing the most used keys far from each other) but Dr. {{w|August Dvorak}} performed many studies and found the mathematically optimal keyboard layout to reduce finger travel for right handed typists. While some claim Dvorak is technically better than QWERTY, QWERTY had become the standard. All the keyboards were laid out in QWERTY format, and retraining the brain after becoming a touch typist is extremely difficult (although some software exists to make this learning process much easier). It has become a [[:Category:Dvorak|recurrent theme]] on xkcd.
**It seems likely that Randall looked at this comic when he made the [[1784: Bad Map Projection: Liquid Resize]], and given that he then released a comic about Dvorak, [[1787: Voice Commands]], the week after that, it seem like this old comic may also have inspired that Dvorak reference, see this [[1787: Voice Commands#Trivia|trivia item]].

{{clear}}

===Winkel-Tripel===
[[File:Winkel-TripelProjection.jpg|frame|The Winkel Tripel projection]]
Proposed by Oswald Winkel in 1921, the {{w|Winkel tripel projection}} tried to reduce a set of three (German: Tripel) main problems with map projections: area, direction, and distance. The {{w|Kavrayskiy VII projection|Kavrayskiy projection}} is very similar to the Winkel Tripel and was used by the USSR, but very few in the Western world know of it.

The comic links this projection to {{w|hipster}} subculture. The hipster stereotype is to avoid conforming to mainstream fashions. "Post-" refers to a variety of musical genres such as {{w|post-punk}}, {{w|post-grunge}}, {{w|post-minimalism}}, etc. that branch off of other genres.

;Trivia
In German "Winkel-Tripel-Projektion" means Winkel's triple projection, and therefore the hyphen shouldn't be there: "Winkel Tripel" or "Winkel tripel".

{{clear}}

===Goode Homolosine===
[[File:GoodeHomolosineProjection.jpg|frame|The Goode Homolosine projection]]
The {{w|Goode homolosine projection}} takes a different approach to skewing a sphere into a roughly circular surface. An orange peel can be taken from an orange and flattened with fair success; this is roughly the procedure that {{w|John Paule Goode}} followed in creating this projection. Randall is suggesting that people who like this map also prefer relatively easy solutions to other things in life, despite those solutions having nuanced problems that are more difficult to address.

Common people make arguments that if normal people would run the United States, then the US wouldn't be in the trouble it is. This is from the belief that career politicians are simply out to make money and will only act in the interest of their constituency when their continued easy life is threatened (usually around election time).

Airline food is another, much maligned, problem. How do you store enough food to feed people on long airplane trips? What kind of food can be served in an enclosed, low-air-pressure environment? The common solution is to use some kind of prepackaged, reheated meal. Randall is saying that the people in favor of the Goode Homolosine wonder why the airlines don't simply order meals from the restaurants in the airport, store that food, and serve it, rather than using bland reheated food.

Older cars burned oil like mad fiends, and oil back then would become corrosive to the innards of an engine, so oil had to be changed often. But, with the introduction of synthetic motor oil and better designed engines, new cars only need their oil changed about every 10,000 to 15,000 miles. A common conspiracy theory is that modern automobile oil manufacturers still recommend that car owners change their oil every 3,000-5,000 miles to "drum" up more business, even though that frequency is unnecessary.

All of these references suggest that people who like the Goode Homolosine projection are fans of easy solutions to problems. However, the solutions would not necessarily work in practice. For instance: the restaurants might have trouble making enough food for the whole plane, and it could get cold before being served; the air conditions [http://www.nbcnews.com/health/one-reason-airline-food-so-bad-your-own-tastebuds-6C10823522 aboard planes] can affect taste, so airlines say they optimize for this; there is no such thing as a "normal" person, and if there were, he/she would have virtually no chance at actually getting into government office; and the Goode Homolosine projection, while mostly resembling a flattened orange peel as suggested by the earlier analogy, does indeed cut down on distortion, but also has serious problems of its own, such as leaving huge gaps of nothingness between the continents, making distances across the oceans difficult to visualize.

{{clear}}

===Hobo–Dyer===
[[File:Hobo-DyerProjection.jpg|frame|The Hobo–Dyer projection]]
The {{w|Hobo–Dyer projection}} was commissioned by Bob Abramms and Howard Bronstein and was drafted by Mick Dyer in 2002. It is a modified {{w|Behrmann projection}}. The goal was to be a more visually pleasing version of the Gall–Peters.

As is discussed in the Gall–Peters explanation, the Gall–Peters was developed to be equal area, so that economically disadvantaged areas can at least take comfort in the fact that their country is represented correctly by area on maps.

Randall associates the Hobo–Dyer projection to "crunchy granola" — a stereotype associated with vegetarianism, environmental activism, anti-war activism, liberal political leanings, and some traces of {{w|hippie}} culture.

With feminism becoming mainstream and alternative genders being more widely accepted, some have begun to invent gender-neutral pronouns so that when referring to a person whose gender is not known they cannot be offended by being referred to by the wrong pronouns. In {{w|Middle English}} 'they' and 'their' were accepted gender-less pronouns that could replace 'he', 'she' as well as be used to represent a crowd, but this usage is considered by some to be grammatically incorrect because of the plural/singular debate ([http://www.merriam-webster.com/video/0033-hisher.htm stupid Victorian Grammarians!]). None of the {{w|gender-neutral pronoun#Invented pronouns|many attempts at popularizing invented gender-neutral pronouns}} have achieved any degree of success in the mainstream.

{{clear}}

===Plate Carrée===
[[File:PlateCarreeProjection.jpg|frame|The Plate Carrée projection]]
Also known as the {{w|Equirectangular projection}}, it has been in use since, apparently, 100 AD. The benefit of this projection is that latitude and longitude can be used as x,y coordinates. This makes it especially easy for computers to graph data on top of it.

According to the comic, the projection appeals to people who find much beauty in simplicity.

{{clear}}

===A Globe!===
[[File:GlobeProjection.jpg|frame|The Globe "projection"]]
In any good discussion there has to be at least one smart-ass. This is a comic about map projections, that is, the science of taking a sphere and flattening it into 2 dimensions. The smart-ass believes that we shouldn't even try: a sphere is, tautologically, the perfect representation of a sphere.

To quote ''{{w|The Princess Bride}}'': "Yes, you're very smart. Shut up."

{{clear}}

===Waterman butterfly===
[[File:WatermanButterflyProjection.jpg|frame|The Waterman Butterfly projection]]
Similar to the Dymaxion, the {{w|Waterman butterfly projection}} turns a sphere into an octahedron, and then unfolds the net of the octahedron, which was devised by mathematician {{w|Waterman polyhedron|Steve Waterman}} based upon the work of {{w|Bernard J.S. Cahill}}.

Bernard Cahill published a [http://www.genekeyes.com/B.J.S._CAHILL_RESOURCE.html butterfly map] in 1909. Steve Waterman probably has the only extant "ready to go" map following the same general principles, though Gene Keys may not be far behind. Waterman has a poem with graphics in a similar vein to this xkcd comic that is worth reading.[http://web.archive.org/web/20120118095915/http://watermanpolyhedron.com/worldmap.html]

[http://www.progonos.com/furuti/MapProj/Normal/ProjPoly/projPoly2.html Polyhedral projections] like Cahill, Dymaxion or Waterman typically offer better accuracy of size, shape and area than flat projections, at the expense of compass directionality, connectedness, and other complications.

The joke is that the person responding deeply understands map projections; anyone who knows of this projection is a person that Randall would like to get to know.

{{clear}}

===Peirce quincuncial===
[[File:PeirceQuincuncialProjection.jpg|frame|The Peirce Quincuncial projection]]
The {{w|Peirce quincuncial projection}} was devised by {{w|Charles Sanders Peirce}} in 1879 and uses {{w|complex analysis}} to make a {{w|conformal mapping}} of the Earth, that conforms except for four points which would make up the south pole.

{{w|Inception}} was a 2010 movie about {{w|meta}} {{w|lucid dream}}ing. It has a complex story that is difficult to follow and leaves the viewer with many questions at the end, and almost needs to be watched multiple times to be understood.

The human brain is not well developed to deal with oddly obvious things. One example is that everyone has a skeleton, but everyone is surprised to see a part of their body represented by an X-ray. Another is the fascinating complexity of the human hand, a machine which is amazingly complex, driven by a complex interplay of electrical and chemical signals; yet is the size of the hand and so useful. A fascination with or fixation on [http://tvtropes.org/pmwiki/pmwiki.php/Main/ContemplatingYourHands such thoughts] is often associated with an altered state of mind brought on by marijuana consumption. Therefore, Randall may be implying that this map would appeal to stoners.

{{clear}}

===Gall–Peters===
[[File:Gall-PetersProjection.jpg|frame|The Gall–Peters projection]]
The {{w|Gall–Peters projection}} is mired in controversy, surprising for a map. {{w|James Gall}}, a 19th-century clergyman, presented this projection in 1855 before the {{w|British Association for the Advancement of Science}}. In 1967, the filmmaker {{w|Arno Peters}} created the same projection and presented it to the world as a "new invention" that put poorer, less powerful countries into their rightful proportions (as opposed to the Mercator). Peters played the marketing game and got quite a few followers of his map by saying it had "absolute angle conformality," "no extreme distortions of form," and was "totally distance-factual" in an age when society was very concerned about social justice. All of these claims were in fact false. The polar regions are horribly distorted, and south of the Mediterranean Sea is "taller" than it should be.

Anyone who loves such a politically charged map that has become popular by way of marketing stunts, Randall would rather not have anything to do with.

{{clear}}

===Title text===
The title text makes a joke that goes to the familiar meme from ''{{w|CSI: Miami}}'', in which the star, David Caruso starts a sentence, then puts on his sunglasses and ends the sentence with a corny pun. In this case, the pun is on {{w|map projection}} and {{w|projection (psychology)|projection}} in psychology. Psychological projection is an unconscious defense mechanism wherein a person who is uncomfortable with their own impulses denies having them and attributes them to other people, and blames these people for these impulses. The Sunglasses internet meme has been used [[:Category:Puts on sunglasses|in other comics]] as well.

==Transcript==
:What your favorite
:'''Map Projection'''
:says about you
:[All of these are organized as Title, a copy of the particular projection underneath, and what it says about you under that.]

:*Mercator
:**You're not really into maps.
:*Van der Grinten
:**You're not a complicated person. You love the Mercator projection; you just wish it weren't square. The Earth's not a square, it's a circle. You like circles. Today is gonna be a good day!
:*Robinson
:**You have a comfortable pair of running shoes that you wear everywhere. You like coffee and enjoy The Beatles. You think the Robinson is the best-looking projection, hands down.
:*Dymaxion
:**You like Isaac Asimov, XML, and shoes with toes. You think the Segway got a bad rap. You own 3D goggles, which you use to view rotating models of better 3D goggles. You type in Dvorak.
:*Winkel-Tripel
:**National Geographic adopted the Winkel-Tripel in 1998, but you've been a W-T fan since ''long'' before "Nat Geo" showed up. You're worried it's getting played out, and are thinking of switching to the Kavrayskiy. You once left a party in disgust when a guest showed up wearing shoes with toes. Your favorite musical genre is "Post–".
:*Goode Homolosine
:**They say mapping the Earth on a 2D surface is like flattening an orange peel, which seems enough to you. You like easy solutions.You think we wouldn't have so many problems if we'd just elect ''normal'' people to Congress instead of Politicians. You think airlines should just buy food from the restaurants near the gates and serve ''that'' on board. You change your car's oil, but secretly wonder if you really ''need'' to.
:*Hobo-Dyer
:**You want to avoid cultural imperialism, but you've heard bad things about Gall-Peters. You're conflict-averse and buy organic. You use a recently-invented set of gender-neutral pronouns and think that what the world needs is a revolution in consciousness.
:*Plate Carrée (Equirectangular)
:**You think this one is fine. You like how X and Y map to latitude and longitude. The other projections overcomplicate things. You want me to stop asking about maps so you can enjoy dinner.
:*A Globe!
:**Yes, you're very clever.
:*Waterman Butterfly
:**Really? You know the Waterman? Have you seen the 1909 Cahill Map it's based— ...You have a framed reproduction at home?! Whoa. ...Listen, forget these questions. Are you doing anything tonight?
:*Peirce Quincuncial
:**You think that when we look at a map, what we really see is ourselves. After you first saw ''Inception'', you sat silent in the theater for six hours. It freaks you out to realize that everyone around you has a skeleton inside them. You ''have'' really looked at your hands.
:*Gall-Peters
:**I ''hate'' you.

{{comic discussion}}

[[Category:Maps‏‎]]
[[Category:Dvorak]]
[[Category:Puts on sunglasses]]

Talk:1949: Fruit Collider

2018-03-18T13:16:25Z

172.68.110.46: Whoops, forgot my signature.

I propose that - for once - we keep the bot-generated text in this explanation section: "This explanation may be incomplete or incorrect."
[[Special:Contributions/141.101.69.129|141.101.69.129]] 15:41, 31 January 2018 (UTC)
:+1! And Ponytail gets banned from particle physics conferences? Or her biology license is revoked. https://xkcd.com/410/ --[[Special:Contributions/162.158.90.108|162.158.90.108]] 16:57, 31 January 2018 (UTC)
::We need to compile a blacklist for conferences people are banned from... [[User:Linker|Linker]] ([[User talk:Linker|talk]]) 18:36, 31 January 2018 (UTC)
:::Hey baby, you can still practice biology without a license... [[User:ProphetZarquon|ProphetZarquon]] ([[User talk:ProphetZarquon|talk]]) 21:39, 31 January 2018 (UTC)
::::.*Pepper Spray*[[User:Linker|Linker]] ([[User talk:Linker|talk]]) 17:16, 1 February 2018 (UTC)

I suppose it's not okay to copy and paste random portions of other articles here in hopes of creating a super explanation?[[Special:Contributions/162.158.75.16|162.158.75.16]] 20:41, 31 January 2018 (UTC)

Does this remind anyone of [https://www.youtube.com/watch?v=rbenrpfuxHs|_ Tom Scott's Piña Collider?]
:no but it reminds of the Higgs boson search by looking and bananas and acorn squash http://sci-ence.org/higgs/

There's a new-year's day ''for trees''? This fact alone deserves its own comic! [[User:ProphetZarquon|ProphetZarquon]] ([[User talk:ProphetZarquon|talk]]) 21:44, 31 January 2018 (UTC)
::A holiday =/= new-year's day - [[Special:Contributions/162.158.50.10|162.158.50.10]] 01:25, 1 February 2018 (UTC)
:::: If you google the jewish holiday for the trees, you will see it is actually a “new year’s day” for the trees. [[Special:Contributions/108.162.216.160|108.162.216.160]] 12:06, 1 February 2018 (UTC)

If only, if only. Orange juice is somewhat sour, and pineapple juice cloyingly sweet, but what would the combination fruit be like?
[[Special:Contributions/108.162.216.154|108.162.216.154]] 02:54, 1 February 2018 (UTC) Gene Wirchenko genew@telus.net
:I believe that is next on the agenda after the peanut/grape enigma is solved [[User:These Are Not The Comments You Are Looking For|These Are Not The Comments You Are Looking For]] ([[User talk:These Are Not The Comments You Are Looking For|talk]]) 01:50, 4 February 2018 (UTC)

This reminds me of https://what-if.xkcd.com/116/, especially title text of the last picture: "A hole bunch of strange, extremely massive drivers were created by collision, but all were extremely short-lived." [[Special:Contributions/162.158.238.190|162.158.238.190]] 10:19, 1 February 2018 (UTC)

Is [https://www.youtube.com/watch?v=l4qFuIXrfVE|_ Banapple Gas] an early result from the Fruit Collider? [[Special:Contributions/162.158.167.174|162.158.167.174]] 05:39, 8 February 2018 (UTC)

The hypothesis presented in this strip has now been empirically tested by [https://www.youtube.com/watch?v=tzJBm3ThjJ8 The Slow Mo Guys].[[Special:Contributions/172.68.110.46|172.68.110.46]] 13:16, 18 March 2018 (UTC)

Talk:1949: Fruit Collider

2018-03-18T13:15:13Z

172.68.110.46: YouTubers tested the hypothesis