# diary of infinity

## Earthquake predictions: even an idiot can be right once in a while

Two days ago, UK newspaper of choice for the illiterate, the Sun, published an article "Disaster" As Moon Closes In predicting earthquakes and tsunamis due to the Moon being at its closest point to the Earth in a long while. The article met with widespread derision. The rest is tragic history....

## A scientific approach to anime

In science we are taught to test the validity of theories by looking for verifiable claims and then testing them. For absolutely no reason at all, I have decided to take the same approach with anime. Some anime takes huge liberties with scientific laws, whereas other anime, for instance Moyashimon, is packed with hard scientific fact which forms the basis of much of the story. Anyway here are two claims made in anime stories which might be tested scientifically, one more easily than the other.
1) Cherry blossom petals fall at 5cm/sec. (source: 5 Centimetres Per Second)

2) If you shorten your skirt by 2cm then you can fly further than yesterday (source: K-On)

Let's look at these claims a bit more closely. In 5 Centimetres Per Second, Akari states that cherry blossom petals always fall at 5cm/sec. Since she gives a constant speed, I think it is safe to assume she is talking about the terminal velocity of petals in still air. In principle this is easy to test, unfortunately cherry blossom season is now over until next year, so a proper experiment will have to wait. However there must be many videos which include the sight of falling cherry blossom so approximate measurements could certainly be made.

From the theoretical standpoint, one might produce a formula for calculating the forces on a cherry blossom petal, however this is not straightforward. In addition to the force of gravity acting on the mass of the petal, and the air resistance acting on the surface area of the petal, we must also consider that the petal flutters, spinning and see-sawing as it falls. This will use up a significant amount of the gravitational force, and the changing orientation of the petal will also alter the air resistance, e.g. when the petal is oriented vertically it will fall much faster. So the motion would be pretty hard to model! To understand the importance of the petals spinning, consider that physicist Richard Feynman once noted that a ball rolling down an inclined plane will only accelerate at 5/7 of the speed that the law of gravity would give you for the angle of slope, since the other 2/7 is used up making the ball rotate. So really unless you are a theoretician of Nobel Prize winning stature like Feynman (who once worked out the equations to explain the rate of wobble of a dinner plate spinning on the end of a stick!) you need to do the experiment first and worry about the theory afterwards (if at all!).

Anyway, next time I will report back on whether I have found any actual footage of cherry blossom falling, also on another question: does the cherry blossom in 5 Centimetres Per Second itself fall at the claimed rate or not? (Preliminary examination says: not!)

Turning now to Claim Number 2 which is made in the OP song of the anime K-On, I will have to defer detailed discussion of that to next time due to lack of time. However it looks to be somewhat tricky, since the obvious way of testing it is to get a girl wearing a skirt to take a flying leap and see if she goes further after trimming her skirt by two centimetres. Needless to say, the repeatability of such an experiment is somewhat problematic. Moreover, note that the specific claim is "further than yesterday" which implies one must compare results of flights that were 24 hours apart, which introduces further variability!

Don’t miss next weeks exciting installment of verifiable anime tales in which I will attempt to recruit a statistically significant number of girls in short skirts to test the K-On claim!

## Mysterious Manga

Every once in a while something wonderful happens. Another chapter of Mysterious Girlfriend X (謎の彼女Ｘ) gets translated! This story cleverly turns what could have been a very ordinary high school romance into something truly exotic thanks to the strangeness of the girl, Mikoto Urabe, who never does anything by the book, as you can see here when she invites her boyfriend to taste her sweat after he comments that she smells nice. (The result is that he has a vision of her in a bikini at the seaside.)

What I like about this kind of story is how it shows that with the right attitude, everyday life can be an amazing and exotic experience, something mysterious, or a great adventure.

Incidentally I learned something interesting recently. I’ve heard it said in the past that only humans have salty sweat. I don’t know if that’s true or not, but I gather from what a nutrionist on Radio 4’s Food Programme said that we only have salty sweat because we eat too much salt. It seems to be the body’s way of excreting excess salt: apparently if you cut your salt consumption enough your sweat ceases to be salty, which means that contrary to popular belief you don’t need to consume more salt in hot weather to replace what you lose due to sweating. In fact in tests done on troops in the desert it was found that taking salt tablets had a negative effect as they needed to consume more water than troops that had nothing to compensate for the salt lost due to sweating.

## Einstein redux

Einstein has often been misquoted as saying, “If I had only known, I would have become a plumber” regarding the malevolent uses to which his discoveries had been put. Actually he was a pretty funny guy, and what he actually said was “If I had only known, I would have become a patent clerk. — No wait, I did!”

## Dear Sir, I am a fish...

Whilst imbibing a pleasant glass of port (the true meaning of the phrase “season of mellow fruitfulness” (yes it’s Autumn here)) the phrase “drink like a fish” popped into my head, immediately followed by the obvious question, “do fish drink?”
Answering this question proved surprisingly easy for these days of poisoned search engines. A guick google of "drink like a fish" + "do fish drink" immediately pulled up the answer on the Audubon website, which is “yes if they are saltwater fish.” The issue is osmosis. For obvious reasons (I’m assuming you understand osmosis here) freshwater fish absorb more water then they need through their skins and so never drink, instead they’re busily pissing out the excess so as not to explode. But saltwater fish have the reverse problem and so they have to, well, drink like fish to prevent dehydration.
May 2013
M T W T F S S
1 2 3 4 5
6 7 8 9 10 11 12
13 14 15 16 17 18 19
20 21 22 23 24 25 26
27 28 29 30 31