What it's about
The weeks towards the end of term are very capable of going pear-shaped, writes Andrew Lochery. A little incident here or a difficult pupil there - the long slog to the Christmas holidays is well under way and pupils are itching for the festive break. So why not inject a little light-hearted enjoyment?
Pupils appreciate spectacular demonstrations with bangs and flashes, and they are always special at the end of the year. One of my favourite experiments is called Flaming Hands and can be used to demonstrate a chemical reaction, illustrate combustion or as an example of a highly exothermic reaction.
Create a mixture of water, washing-up liquid and glycerol in a plastic trough and then bubble some methane gas from the lab tap through the mixture. The methane gas will become trapped inside the washing up liquid and glycerol, creating your very own "flammable bubbles". Now you can build a tower of bubbles, or run them along the length of a bench like an explosives fuse.
Alternatively, if you are feeling brave, place your hand in a bucket of cold water and then place some of the bubbles on your palm. Carefully setting light to the bubbles will send the class into spontaneous, excited cheers.
Hopefully, the demonstration will trigger inquisitive questions from the class and open up more avenues to explore. Good, insightful questions may even allow you to develop links with ideas, such as energy transfer and the use of fossil fuels.
Where to find it
There are practical combustion ideas on the TES science forum, where science teachers have come up with fun and festive ideas for experiments.