Episode 7

Jem Stansfield tests out new braking systems that won't burn money, Liz Bonnin looks into the origins of speech by trying to wipe out someone's speech cortex, Dallas Campbell takes part in a sea race with Dame Ellen MacArthur to try and explain why British summers are rubbish and Dr Yan Wong explains a common optical illusion.

The programme is co-produced with The Open University.

For more ways to put science to the test, go to the Hands-on Science area at www.bbc.co.uk/bang for details of our free roadshow touring the UK and activities that you can try at home.