The other reactions that I mentioned here are both quite spectacular – thermite and the potassium dichromate volcanoe.

The volcano experiment involves creating a small heap of orange potassium dichromate and sticking a length of magnesium ribbon in the middle to ignite it. The magnesium is lit by a bunsen (don’t look right at the flame), and then it does its stuff. The potassium dichromate starts to spark and splutter, turning from an orange dense material into a fluffy green substance. It seems to double or triple in volume and gives the impression of producing something from nothing. Eventually you are left with a fizzing sparking caldera of dichromate surrounded by green powder and you understand why it was compared to a volcano.

Thermite usually inspires great nostalgia in all those who saw it demonstrated at high school. I have no recollection of it, but I do recall making quite a bit of gunpowder, some with a decent quantity of magnesium powder, and also home made sparklers. Thermite though, pretty impressive and useful stuff.