Fill the jar halfway with vinegar, then add a few drops of one colour of food colouring and some glitter. Squeeze in some dish soap, stir, and place the jar on a tray. Now have your child add in a heaping teaspoon of baking soda, stir again, and watch the foaming begin! The soap makes it foam rather than fizz. To keep the reaction going continue adding baking soda and vinegar when the foam starts to slow. To make it change colours, add a tablespoon of vinegar mixed with one color of food colouring every so often. Make sure to dump the coloured vinegar into the center of the brew.
Tip:Stir It! My kids discovered that the more they stirred the mixture the faster and crazier the reaction!