The History of Chemical Weapons

As Syria agrees to destroying its chemical weapon stocks, Adam Rutherford looks at how you solve a problem like Sarin. Dr Joanna Kidd from King's College London gives us a potted history of chemical weaponry.

Environmental toxicologist, Prof Alastair Hay, from Leeds University has worked on chemical warfare issues for four decades. In the 1990s, he identified mustard gas and sarin residues from soil samples in Iraq, confirming their use by Saddam Hussein. He talks to Adam about the challenges of destroying chemical weapons in Syria.

Reporter Roland Pease looks at a new phone app, OpenSignal, which uses your smartphone's sensors to help improve weather models.

Today, London Underground workers are starting to boycott a new clock-in system, which uses their fingerprint for identification. Meanwhile, Apple fans are camping outside stores waiting to buy the new iPhone, which features a fingerprint scanner.

Adam talks to Dr Farzin Deravi from the University of Kent about how fingerprint identification works and whether it can be fooled with a gummy bear. Plus he asks technology journalist Kate Bevan if we should worry about the security issues surrounding biometric passwords.

Finally this week, Dr Pedro Viegas shows us his instrument - a dino drill. It's being used to uncover the Bristol dinosaur, a 210 million year old Thecodontosaurus.