You will need
Washing up liquid
1.Fill your glass half full with water.
2.Add 3 teaspoons of baking soda.Stir until it disolve's
3.Add a good squirt of washing up liquid and give it a stir
4.Add food colouring and stir
5.Quickly add in 1/4 cup of vinegar and enjoy your experiment.
Both times it worked very well. We figured that if you used more baking soda it would explode more.