Episode 8

Jem Stansfield builds a microwave death ray to prove the existence of invisible and untapped energy, Liz Bonnin takes on the nature versus nurture debate with a troop of monkeys, Dr Yan Wong explains how gyroscopes work with the help of a couple of office chairs, and Dallas Campbell decides to save the world of physics from crisis by trying to find a missing bit of the universe.

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 the programme's free roadshow touring the UK and activities to try at home.