In the second episode of the series, the team take on more scientific challenges. Liz Bonnin looks at the science behind sunburn, and discovers how much sun damage she has on her face. Dallas Campbell tries to make museum visitors younger and smarter in a series of psychological experiments. And Jem Stansfield proves that wheels don't have to be round by building a square-wheeled skateboard. The programme is co-produced with the Open University. For more ways to put science to the test, go to www.bbc.co.uk/bang and follow the links to The Open University.