## Plus Blog

June 3, 2008
Tuesday, June 03, 2008

### Boomerangs in space

A boomerang has been thrown in space, and lo and behold, it returns to its thrower, just like on Earth.

Japanese astronaut Takao Doi threw the boomerang on request from world boomerang champion, compatriot Yasuhiro Togai onboard the International Space Station.

"I was very surprised and moved to see that it flew the same way it does on Earth," Doi was quoted as saying in the Mainichi Shimbun.

Thanks to wawawamovie for the following video of the boomerang.

If you would like to read more about the physics of throwing a boomerang (and why it is no surprise that it should fly in microgravity as long as there is air), read the Plus article Unspinning the boomerang. And to make your own boomerang, read the Plus article Bang up a boomerang.

posted by westius @ 3:59 PM

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June 3, 2008
Tuesday, June 03, 2008

Mathematics is used in interesting, and often less than accurate, ways. Newspapers present graphs showing apparently correlated variables, but with a little thought, some of the time you will find that whilst it looks like two variables are connected, there is actually no cause and effect. An unscrupulous media can draw connections where they don't exist for political ends and politicians have been known to confuse cause and effect entirely. So what really is behind the rise in oil prices? Could it be the humble game of cricket?

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posted by westius @ 5:00 PM

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June 3, 2008
Tuesday, June 03, 2008

### I will derive!

Mathematicians are known to be good musicians. Here is a mathematical parody of the Gloria Gaynor song, "I will survive". I particularly like the lyrics:

And so now I, I will derive.
Find the derivative of x position with respect to time.
It's as easy as can be, just have to take dx/dt.
I will derive, I will derive, I will derive!

posted by westius @ 3:05 PM

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June 1, 2008
Sunday, June 01, 2008

Barry Phipps is the first interdisciplinary fellow with the Kettle's Yard gallery in Cambridge. His remit is to develop projects of an interdisciplinary nature, to find the common ground between things. Plus talks to Barry about breaking down the barriers between artists and scientists and creating greater dialogue because, as Barry says, science and art are intrinsically related at the centre, and there is no stepping away from one to be another. This podcast accompanies the career interview in issue 47 of Plus.

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posted by Plus @ 3:42 PM

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May 23, 2008
Friday, May 23, 2008

### United Kingdom - Nil Points

It is one of my favourite times of year, and I'm not even European.

The Eurovision Song Contest to Australians is a strange mix of bad 80s music, songs about "joy", "love" and "unity", amazingly good-looking hosts, scantily dressed Eastern Europeans and reality TV winners from Western Europe.

But another reason I love it is because it is about politics and maths. For the first time in my life, living in the UK, I get a chance to vote for the winner and watch it live instead of having to ignore radio reports (of course it's all over the news) till the Sydney Sunday evening replay.

The voting of Eurovision is a complex interaction of politics and voting blocks. Each country votes in a popular vote, in which they cannot vote for themselves, and each country has equal voting power. Voting is often based on politics — Cyprus and Greece nearly always exchange votes — and I can remember the days when Ireland and the UK were similarly connected. On the other hand, France does not vote for the UK and the Balkan states have mixed allegiances.

Eurovision is a perfect example of what mathematicians call a complex system. This consists of a group of objects (countries) which interact with each other (by giving each other points for their songs), and this interaction can be tracked over time. A statistical analysis of the system can then give some insight in the nature of the interaction. For example, it can show whether certain countries form cliques that always vote similarly, or whether a country's voting is largely "in tune" with that of the whole group.

Some time ago a team of Oxford scientists performed statistical tests to see whether the voting behaviours of different countries are in some way related. In every statistical test you need a "control experiment" to compare your results to. Suppose, for example, that two countries always seem to vote the same way. Then, before you can deduce that their musical tastes are indeed related, you need to show that the two countries vote the same way significantly more often than would happen in a song contest in which the countries' voting is truly independent. To create such a control experiment, the team simulated a "random song contest", in which each country assigns its points randomly to 10 other countries. They then compared the results of all their tests to the random contest.

One such test involves seeing whether voting relationships between countries persists over time. If, for example, country A gives and/or receives points from another country B over a long period of time, then we can deduce that in some way the musical tastes of the two countries are related. Carrying out the same analysis between country A and all other countries in turn will show whether or not country A is "in tune" with the rest of Europe.

Another test observes the number of countries to which a given country A has awarded points and from which it has also received points. If a country has many such "reciprocal links", then one might deduce that its musical taste harmonises well with that of Europe in general.

The remaining tests were devised to identify cliques of countries whose voting behaviour is correlated. For example, the team checked to see whether two countries that have both received and/or awarded points to a third country are likely to give or receive points from each other.

And the results of the study? Well, you'll just have to read our Plus article United Kingdom - twelve points for more information on the statistical tests, and don't forget to vote!

posted by westius @ 11:44 AM

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May 20, 2008
Tuesday, May 20, 2008

### More movies and maths

Maths in the movies is obviously in vogue these days.

The following video comes from Triple J in Australia, and is a nice summation of how maths has been used as a tool for plot development over the years.

Thanks to Marc Fennell, the host of the show, for the permissions.

posted by westius @ 3:35 PM

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