Watch science in action when you combine the carbonation of soda pop with the porous surface of Mentos mints.  This combination causes the release of the soda’s carbon dioxide, which then creates tons of fun foam.  You can get creative with this experiment by using a variety of sodas to see what kind creates the highest, most powerful geyser!
What you need:
2-liter bottles of: Coke, Diet Coke, Sprite, mineral water
2-3 tubes of Mentos mints

Head outside and line up your soda bottles. Tip: Don’t put bottles too close to anything that you would not want to get “sticky.”  Unscrew the caps and drop five Mentos tablets into each bottle as quickly as you can and get away!  These geyers will start spraying as soon as the Mentos are dropped into the bottle.  You could also pour some vinegar into an empty soda bottle, add a little baking, and see how that compares.