Stargazing Challenges

Blue Peter presenters Helen Skelton and Barney Harwood want to learn more about the solar system so they challenge scientists Helen Czerski and Jem Stansfield to find out more. They look at how to make telescopes and rockets, and use a toilet roll to measure the distances between planets.

Explosions: How We Shook the World

Engineer Jem Stansfield is used to creating explosions, but in this programme he uncovers the story of how we have learnt to control them and harness their power for our own means. From recreating a rather dramatic ancient Chinese alchemy accident to splitting an atom in his own home-built replica of a 1930s piece of equipment, Jem reveals how explosives work and how we have used their power throughout history. He goes underground to show how gunpowder was used in the mines of Cornwall, recreates the first test of guncotton in a quarry with...