You are going to need:
Film canister
Baking soda
Vinegar
Food dye
Duck tape or paint to decorate
White vinegar
Toilet paper

Step 1: Step 1

Take off the lid of your canister , paint the canister ,or cover it with duck tape.

Step 2: Step 2

Fill up the canister 3/4 of the way with vinegar. Then, color the vinegar blue.

Step 3: Step 3

Put about a teaspoon of baking powder into a square or toilet paper. Then, twist it up.

Step 4: Step 4

Place the toilet paper into the canister. (I had to change the toilet paper and baking powder). Quickly put the lid on and shake the canister.

Step 5: Done!!!

After you shake it you get blue foam. This is what it looks like on the outside when it is foaming ,and inside after it is finished. I recommend having some friends over and doing many at once. You can try it with larger containers and mix up the proportions of baking powder and water.