## Wild About Math bloggers 1/14/11

[ The 1/21/ edition is at Equalis. Here's last week's article. ]

Here's my roundup of this second week of January!

Carnival of Mathematics #73 is up at Walking Randomly.

Maxwell's Demon has an interesting spin on the prisoner's dilemma, in a group setting.

Last semester I offered my students $1,000,000 dollars. They turned me down. This was lucky, despite the money and glamour of academic mathematics, I do not have a million dollars. The game was simple. The class of 100 each had to write a number. The highest number won. Of course there was a catch, the prize was $1,000,000 divided by the winning number. The best outcome for the students as a whole would come if everyone wrote 1, $10,000 is not a bad return for a lecture. Of course if everyone is writing 1, the person who writes 2 wins and makes far more for themselves. What happened?

Here's a very interesting piece of number trivia:

Every number greater than 8 has at least two letters in common with each of its neighbors.

Hat tip to Futility Closet.

Grey Matters has a nice and timely article on how to figure out the day of the week for any date in 2011. For those of you who are a bit intimidated with figuring out the day for any date of any year this is an excellent place to start.

Dan at Math for Love has a great game for a group of kids that helps them to think about how numbers factor. Brilliant!

Here's a great magic trick, all based in Math.

When the magician leaves the room, the trickees lay out eight coins in a row deciding which side is turned up according to their whim. They also think of a number between 1 and 8 inclusive. The magician’s assistant then flips exactly one of the coins, before inviting the magician back in. The magician looks at the coins and guesses the number that the trickees thought of.

I'll leave you with this new video with Vi Hart discussing and illustrating visualizations of hyperbolic planes and other cool stuff!

[youtube]http://www.youtube.com/watch?v=qsE2UKkIKXU[/youtube]

.mau.January 26th, 2011 - 01:58

Back at the time of his column on Scientific American, Douglas Hofstadter called a Lurking Lottery under the same concept as Maxwell’s Daemon.

nateJanuary 26th, 2011 - 15:24

Could you write a number less than one? If, for example, each person submitted .000001, there would be substantially more money involved. I wonder if a big enough prize would deter someone from considerations of breaking the pact to win alone, if all could see that winning alone would make one fear the 99 wanting revenge. I expect the probability of revenge increases with the amount of money of which one has been deprived.