New Scientist has teamed up with Discovery Channel's MythBusters to attempt to solve a mystery. Thermite and ice can make an explosive combination, so don't try this experiment at home - watch it safely on the web at www.mythbusters-thermite.notlong.com.

We want to find out why the explosion happens. Thermite is a mainstay of pyrotechnics, comprising a mixture of metal and metal oxide powders that burn at extremely high temperatures in a tightly focused area. Thermite is not, by itself, explosive, but if you ignite a bucket of thermite on top of blocks of ice, there will be an enormous bang once it has burnt through the bucket.

MythBusters presenters Jamie Hyneman and Adam Savage are seeking a convincing scientific explanation of this violent reaction (see Interview: The mythbusters). Can Last Word readers solve the mystery?

See the MythBusters offer the challenge