3 Tablespoons Vegetable Oil (depending on the size of the jar)
Food Colouring
Fill the jar about 3/4 full with warm water.
In a separate bowl pour three tablespoons approx. of vegetable oil.
Carefully put drops of food colouring into the oil.
Mix with a fork.
Pour the oil and food colouring mix into the jar of water.
Watch as the coloured drops sink down into the water and mix together creating a firework effect. (You might need to be patient as when we did this it took a while to start.)