Fireworks in a Jar experiment – 3 easy steps to try!   Fireworks in a Jar is one of our favourite demonstrations and is so easy to do. The colours explode into the water and create a tumbling rainbow which is mesmerising to watch, the colourful columns change shape as they gracefully fall, and new colours are formed as the original ones mix together. This activity is not just pretty to look at, it creates an opportunity for talking and teaching about immiscible liquids, gravity & diffusion, which all play a part in this colourful display.