Volcanoes emit millions of tonnes of gas into the atmosphere every day, but which gases are being produced? A small volcano from New Zealand is active and scattering dust, smoke and vapour every day. A volcanologist is investigating which gases are produced by the volcano. He collects the samples by inserting a tube inside the volcano. He identifies the main gases produced as water vapour (80%) and carbon dioxide (15%). Sulphur and hydrogen chloride are also produced.

This clip is from:
Science Clips, Gases around Us
First broadcast:
11 October 2007

Teachers could show the pupils the clip and then hold a discussion about volcanoes in general. Do pupils think that all volcanoes are equally dangerous? Once the discussion has got going, pupils could determine that dormant volcanoes may be perceived as less dangerous but in fact their size and location could make them more of a threat to humans. After this initial discussion, pupils could then go on to research volcanoes around the world. They can use the internet or research books to aid their understanding. They could find out facts about a few of them and use these to create a set of ‘Top Trumps’ style cards allocating scores according to their threat and size.