Teaching Physics
by Jeff
Image text: Space-time is like some simple and familiar system which is both intuitively understandable and precisely analogous, and if I were Richard Feynman I'd be able to come up with it.
This comic is about how it is very difficult to teach Physics because the metaphors that are frequently used are not perfect and for students, it often makes it more difficult. Gravity and the rubber sheet is a common metaphor, but for the student in the comic, it does not make sense how the massive objects are pulled down. And again in the last frame, the metaphor for space-time bores the student. (On a side note, what annoying type of student would say "Boooooring" at your professor/teacher. Brat.)
The image text is what constructs an ideal metaphor because it is "intuitively understandable and precisely analogous". The metaphors in the comic above are not both of those things. Richard Feynman is a famous physicist who worked in a lot of different areas including quantum mechanics. Feynman came up with the Feynman diagrams, which were pictorial representations of the behavior of subatomic particles and their mathematical scheme.
Probability
by Jeff
Image text: My normal approach is useless here, too.
Megan and Cueball are sitting at the bedside of a sick person and they are presented with the probability of how long the person will live. In the second frame are the years and probabilities. The first frame has the more detailed probability line.
This comic is probably a reference to Randall's sick family member which caused him to take a leave of absence from the comic a few months ago.
Fairy Tales
by Jeff
Image text: Goldilocks' discovery of Newton's method for approximation required surprisingly few changes.
Classic xkcd here, with math and fairy tales mixed together.
The eigenvectors of a square matrix are the non-zero vectors which, after being multiplied by the matrix, remain proportional to the original vector (i.e. change only in magnitude, not in direction). For each eigenvector, the corresponding eigenvalue is the factor by which the eigenvector changes when multiplied by the matrix. (Thanks Wikipedia!) So, in this way, the prince would have used a eigenvector and corresponding eigenvalue to match the shoe to its owner.
I'm not sure why it makes sense to change out Inductive for "Snow" in Snow White. But, inductive reasoning is the process of making an educated guess. The mom also replaces 7 in 7 Dwarves with N-1, which obviously is another common math term.
In the next fairy tale, The Three Little Pigs becomes "The Limit of x as it approaches infinity Little Pigs".
In the image text, Newton's method for approximation is a method for finding successively better approximations to the zeroes (or roots) of a real-valued function. In Goldilocks, if you remember, she finds successively better porridge and appropriately sized chairs in a house where three bears lived. In the same way, in the Mom's version of the fairy tale, she would find successively better approximations to zeroes instead of porridge and chairs instead of successively better bowls of porridge.
Commenter quiz: which fairy tale was the mom reading in frame 2? I've got an ant gathering food and a grasshopper, but I'm not sure which fairy tale that is.
Compass and Straightedge
by Jeff
Image text: The Greeks long suspected this, but it wasn't until April 12th of 1882 that Ferdinand von Lindemann conclusively proved it when he constructed himself the most awesome birthday party possible and nobody showed up.
This comic is funny because Cueball is a stick figure so technically it is possible to create friends with a straightedge and a compass. Just one circle with the compass and 5 lines with the straightedge.
There is also a possible reference the "Straight Edge" a movement that refrains from taking drugs or drinking alcohol. So, the alternative interpretation is that Cueball was straight edge in high school so therefore had no friends.
Ferdinand von Lindemann was a real German mathematician. In 1882, he proved that pi is not a zero of any polynomial with rational coefficients or a transcendental number.
Complex Conjugate
by Jeff
Image text: Fun fact: if you say this every time a professor does something to a complex-number equation that drops the imaginary part, they'll eventually move the class to another room and tell everyone else except you.
Ok, so to understand this comic, you have to understand the phrase "This just got real" or "This shit just got real" which is an American (at least I think its just American) phrase that is said when something turns from a joking situation into an actual confrontation or other serious situation.
In this comic, the Physics professor multiplies the wavefunction by it's complex conjugate which (as it says in the image text) drops the imaginary part, which means they are only working in real numbers. Imaginary numbers are square roots of negative real numbers. Real numbers are all the other number options such as -1, 12 and 42.6.
Convincing
by Jeff
Image text: And if you labeled your axes, I could tell you exactly how MUCH better.
This comic is a typical xkcd compilation. Relationships, math, graphs and of course, the twist.
Cueball wants to get back together with Cutie (or Megan), but she declines and shows him a graph showing why. She thinks that the downward trend of the graph will convince him that their relationship is also in decline. But, Cueball takes that as this is a girl who does not follow proper protocol and label her axes (plural for axis) on her graph. We do not even know the unit of measure on the graph, let what each axis corresponds to.
For all we know, the horizontal axis could be labeled "Time" and the vertical axis could be labeled "Crappiness of Relationship" or "Unawesomeness of Relationship". In that case, a downward trend would be positive.
In the twist, Cueball sees that he can do better than this girl and switches his position and decides HE is going to break up with HER.
Guest Week: Bill Amend (FoxTrot)
by Jeff
Image text: Guest comic by Bill Amend of FoxTrot, an inspiration to all us nerdy-physics-majors-turned-cartoonists, of which there are an oddly large number.
The top comic is a reference to this famous xkcd comic. The sudo command in linux allows a user to run as a "super-user", thus allowing them to execute the command they wish.
The next comic is a pun on the word "attractive". The girl thinks he is using it in the fashion that he likes he and is interested in her. He's using it in the gravitational pull way.
The next comic is a reference to the Heisenberg Uncertainty Principle. Which, if you read explain xkcd, you should know like the back of your hand.
The third comic, is a play on the sound of the word "aye". Aye is a word used when taking a verbal vote that is used to signify a positive, like yes. Additionally, aye sounds like the letter i. In this case, the mathematician in Congress is voting the square root of -1, which comes out to an imaginary number known as i. And since i sounds the same as "aye", that is how a mathematician votes.
Five-Minute Comics: Part 3
by Jeff
Image text: Resulting in The Little Rock 9x + C.
Top: Reference to the Japanese attack on the American base of Pearl Harbor in Hawaii that brought the US into World War II.
High Middle: I believe this is a reference to perl scripting language. And the comic is also a reference to how much more persuasive you can be if you say that you saw a study defending your argument.
High Left: Don't know why women try to breastfeed anyone on the bus. I haven't seen that happening on all the buses I've been on. Maybe I've been on the wrong buses?
High Right: Coke and pop rocks makes a crazy foaming explosion in your mouth, but I'm not sure where the phone and creepy girls comes from.
Lower High Middle: This is a reference to the Billy Joel song called "We Didn't Start the Fire". But, I guess, the police suspected him anyway.
Middle Left: In 1957, Eisehower ordered the Little Rock Arkansas Schools integrated, which means that there were no longer black schools and white schools, there were just schools. But, of course integrate can also have a math meaning and in this comic, the police are putting up an integration symbol next to the school. The image text is also a reference to this.
Middle Right: This one is pretty self-explanatory. Typical horror movie set up, this time with smart phones.
Lower Middle Left: This is a reference to the children's story, the 3 Little Pigs. As the story progresses, each pig builds his house out of stronger material to try to fend off the Big Bad Wolf. In this comic, there is a lot more pigs, and a lot more increasingly strong materials. The elements in the comic is strontium which is (thanks Wikipedia!) is a chemical element with the symbol Sr and the atomic number 38. An alkaline earth metal, strontium is a soft silver-white or yellowish metallic element that is highly reactive chemically.
Lower Middle: The phrase "Fastest gun in the west" is usually reserved for how fast a cowboy can draw. In this case, this is a pun on that and the gun actually "runs" races.
Lower Right: Scientists use centrifuges to separate elements. In this comic, the pun is on the phrase "separate the men from the boys", which is a typical American (at least I think it's just American) phrase for a hard task that is forces you to see who is capable and who is not.
Bottom Left: Typical xkcd. SETI and Narnia in one comic. If you have seen the movies or read the Narnia series by CS Lewis, time works differently once you go through the wardrobe to get to Narnia. Time passes much more quickly in Narnia. So, Cueball is capitalizing on that by putting his computer in Narnia to be able to do more work in less "real" time. SETI@home is the search for extraterrestrials by using extra processing power of computers that go to the screeensaver. Foldilng@home is a similar idea, but this is with protein folding.
Bottom Right: This is a reference to the old TV show, the Honeymooners in which the male character, Ralph always threatens his wife by saying "One of these days, Alice, Pow right in the kisser". Which is an old-timey threat of him hitting her in the mouth. In this comic, instead of the "pow" sound effect, all the waterslide sounds are used.
Five-Minute Comics: Part 1
by Jeff
Image text: The wolves thin the RAID arrays, removing the slowest and weakest disks to keep the average seek speed high.
The set up for these comics are explained at the top by Randall, so let's dig into a few.
Top left - Jupiter, the planet, comes so close to the Earth that it becomes a character in the comic. And because it is so massive and has a huge gravitational field, it asks the characters if they would like to use that pull as a slingshot. In that case, some object in space would fly close enough to a massive body to increase its speed using the gravity of the planet or star while circling the object and "slingshot" themselves out the other side.
Top Middle - A pony is a typical or stereotypical young girl's dream gift. In this case, instead of rescuing the girl from the well, he pushes a pony down there too, I guess to make her feel better.
Top Right - Just like nature conservatories have reintroduced wolves to back to nature, this systems administrator has reintroduced wolves to his nature, the server room. The image text is connected to this comic and references how wolves will thin herds of animals by attacking the weakest and slowest animals. In this case, the admin is speaking in the text. Obviously, wolves cannot eat RAID hard drives. But, as usual, Randall is comparing two widely different ideas. In the RAID HD case, you would want to thin the slowest RAID arrays so that you would be writing data only to the fastest drives. Because the drives are RAID arrays, there is multiple copies of each data, so the array would not miss a beat if one drive (or two) were taken by wolves.
Middle Right - I'm not so sure this one makes any sense, because it involves the magic flute from Legend of Zelda the video game series, Bach and Wagner, two famous composers, and a ring cycle from Tron. Seems like something out of a strange dream.
Middle Upper Right - Given Randall's predilection for "Yo Momma" jokes, this is another one gone wrong.
Bottom - This is a standard xkcd comic. Take a solid idea over the first three frames and then take it farther and then too far. In this case, it ends up with a hotness rating of a girl in your bio class wearing your mom's skin. Uh, gross.
If anyone can decipher Middle Left, I'd love to hear what you think. Only thing I can think of is Trig like Trigonometry.
Applied Math
by Jeff
Image text: Dear Reader: Enclosed is a check for ninety-eight cents. Using your work, I have proven that this equals the amount you requested.
Donald Knuth is a computer scientist that has written several computer science textbooks and he offers rewards for anyone finding errors in his publications. The first error found in each book is worth $2.56. Other errors and suggestions are worth less than $2.56, but a check is still sent out if Dr. Knuth finds them to be reasonable.
In this comic, Black Haired Girl uses a proof to invalidate logic itself. And then, she writes a letter to Dr. Knuth to collect her money for the 1,317,408 errors in The Art of Computer Programming at $2.56 each.
In the image text is the reply from Dr. Knuth in which he uses Black Haired Girl's logic disproving proof to evaluate her work down to 99 cents.