2100: Models of the Atom
|Models of the Atom|
Title text: 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.
| This explanation may be incomplete or incorrect: Created by a CONFUSED ATOM. Please mention here why this explanation isn't complete. Do NOT delete this tag too soon.|
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This comic humorously describes the changing view of how atoms work.
The first model shown, in 1810, is said to be a "small hard ball model." Around this time, John Dalton came up with the most famous maxim of chemistry: "All stuff is made of atoms." Dalton used the idea to explain what is today known as stoichiometry. Thus humans thought up the idea of atoms – but in lieu of any ideas of how they work, the scientific community likely thought of them as "hard round balls"; thus the name described here.
In the late 19th and early 20th centuries, the study of these "atom" things faced a crisis: where would the newly discovered "electrons" go? In 1904, physicist 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 "plum pudding model", the second model on the comic, called this because people imagined the positively charged mass as a "plum pudding". (The title text references Thomson as well, along with the humorous observation that plum puddings themselves are made of atoms.)
This was one of many competing ideas in the formative years of what-are-atoms-made-of-ology, where Randall claims a 1907 "tiny bird model" (the third model shown) would fit in well. But ultimately, the tentative winner in the battle was the model of Thomson's student Ernest Rutherford, who discovered that the positive charge seemed to be in the center of the atom, and put down his Rutherford model, or "planetary model", in 1911, where electrons orbit a positive charge. This is the fourth model put down.
But there were a few problems; Maxwell's equations complained, for instance, saying that accelerated (here: flying on the circle instead of a straight line) charges like the electrons would loose energy emitted as electromagnetic waves and would quickly orbit into the nucleus. Niels Bohr patched the model up with the newfangled idea of quantum mechanics, creating his "Bohr model", the fifth model shown here, in 1913.
If this sounds like today's model, you didn't pay enough attention; note that at this time, nobody thought of splitting up the nucleus into protons and neutrons. But pretty soon people noticed that protons and neutrons existed; Randall facetiously suggests a "nunchuck model", the sixth model shown, of a packet of protons swinging a packet of electrons around. But more seriously, 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 the seventh model shown here.
The eighth model shown is a "538 model" in 2008. 538 is a statistical analysis website that gained fame in 2008 for predicting every race but 2 correctly in the US presidential election. 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 pie chart shows the composition of neutrons, protons and electrons, 38%, 31%, and 31% respectively. This could represent gallium-69, the most abundant isotope of gallium, with 31 protons, 31 electrons and 38 neutrons.
But is the Chadwick model what scientists endorse today? No! Today physicists subscribe to a quantum model, which is the ninth model shown here. Instead of electrons, there are quantum clouds, or more simply, the parts of the atom aren't in any particular point, but rather a probability field of possible locations. 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).
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.
|18||Maximum number of electrons in the third (M) electron shell|
|π||The number pi present in many physics equations, often as its double value (2π); also in the definition of the reduced Planck constant present in quantum-mechanical equations.|
|173||Possibly a typo (should be 137) referring to the fine structure constant which value is approximately 1/137|
|This transcript is incomplete. Please help editing it! Thanks.|
[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.]
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.]
Plum pudding model
[A bigger circle, with four birds on the surface and music notes above.]
Tiny bird model
[A small circle with dots circling around it, drawn with paths.]
[A circle with a plus sign with three circles around it, each with a dot.]
[A nunchuck swinging, with the left stick filled with circles with plus signs and the right stick filled with circles with minus signs.]
[A nucleus with three circles around it, each with a dot.]
[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.]
[A circle, with (...)]
[A circle with numbers above.]
Numbers: 18, 0.1, π, 173, √2, 4i
"Small hard ball surrounded by math" model
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