The plan was to give six 45-minute class assemblies to cover the whole school – 330 pupils – over the course of the day. The shows needed to be visual, quick, and easy to explain. The need to use everyday materials bought from the supermarket considerably eased the risk assessment!
We started on gases with the volcano experiment, using baking powder and vinegar. The audience was most surprised by the reaction, and the addition of some food colouring made for a very spectacular large red froth. Then it was on to liquids and the red cabbage indicator demonstration, which included unwrapping and shredding for all to see, which added to the tension. The loudest gasps of the day came when we added vinegar and the colour instantly changed from blue to red. Other colours were seen with lemon juice, cola and bleach.
After making a basic lava lamp with cooking oil, we moved on to solids and ‘magic sand’ – made at home using suede shoe super protect spray. The physics contribution was a demonstration of the vacuum created by an upturned half-filled wine glass on cardboard, and finally it was on to maths, where the triple stack dice trick created much amazement.