There is another amazing experiment which is similar to this one, but has even better results.

What you do is mix ammonium fertiliser with another nitrate-based compound.

Then insert a detonator and a timing device ... hey presto.

I was reading in the paper today about the amazing reaction you get from this, apparantly it is all the rage in some middle-eastern countries, although it seems to be catching on in London and New York and places like that now.

Trendy young people are even accessorising this by combining the chemicals in a specially made 'belt' or waistcoat rather than the more traditional rucksacks.

There is aTV programme where you can see the amazing results of this - News at 10, I think it's called.