1) Get a two-liter bottle of soda. We found that Diet Coke works better than anything else.
2) Get a pack of Mentos, the mint kind.
3) Make a paper tube that is the same diameter as the Mentos.
4) Put an index card under the tube, and fill the tube with Mentos.
5) Open the two-liter bottle.
6) Put the tube with the flashcard under it on top of the two-liter bottle and align the tube with the opening in the bottle.
7) Quickly remove the flashcard so that all of the Mentos fall into the two-liter bottle at once, and get out of the way.
8) Watch.
