## News from the world of Maths

How would it feel to look in a mirror and see not your own reflection but instead how you would look as the opposite sex? You can explore this strange alternate reality at this year's Royal Society Summer Exhibition where scientists from Queen Mary, University of London and University College London will use mathematical wizardry to produce gender reversed images of faces.

*Plus* has teamed up with the Royal Society Summer Science
Exhibition 2011 to reveal the maths behind some of the science on show. We have chosen two exhibits from this year's participants and produced
postcards for people to pick up at the stand, accopmanied by *Plus* articles to reveal some of the the maths behind
them. Read the articles and if you
can't make it to the exhibition yourself, you can also download pdfs
of the postcards.

Airport security staff have a daunting task. With impatient queues looming over them they need to search x-ray scans of cluttered suitcases for several items at once: knives, guns and bombs. How can we ease their task and make sure they don't miss a crucial item? To find out, scientists are trying to understand how we humans take in visual information. The humble triangle plays a crucial role in the experiments they perform.

A Rubik's cube, you'll be pleased to hear, can always be solved in at most 20 moves, no matter how badly it was scrambled up to start with. Mathematicians have proved that that's true. But what if you're wrestling with a larger cube that has more than three little cubes in a row?

*Plus*!

We often think of mathematics as a language, but does our brain process mathematical structures in the same way as it processes language? A new study published in the journal *Psychological Science* suggests that it does: the process of storing and reusing syntax "works across cognitive domains."

Kneeling in the mud by a country road on a cold drizzly day, I finally appreciated the wonder that is a lever. I was trying to change a flat tyre and even jumping on the end of the wheel wrench wouldn't budge the wheel nuts. But when the AA arrived they undid them with ease, thanks to a wheel wrench that was three times the size of mine. There you have it ... size really does matter!

How big is the Universe? And how small is the smallest thing within it? This cute website developed by Cary Huang puts things into perspective. It lets you explore the entire range of scales, from the smallest length (the Planck length) all the way up to the entire Universe, via atoms, people, giant earthworms, planets, galaxies and more.