Experiments With Mentos

The reaction that occurs when Mentos mints are dropped into a bottle of soda is something most would not expect -- a large geyser of soda shooting from the bottle. But that is what happens, turning two common objects into a safe and easy home science experiment. The experiment is not new, but has only gained popularity in the last five years after a video of the Mentos experiment appeared on the Internet.

How it Works

When a Mentos candy is dropped into soda, an explosion occurs, shooting the soda straight into the air. Questions remain about the exact cause of the explosion, but many point to the carbon dioxide in the soda bottles, the make-up of soda and Mentos and the amount of pressure used to bottle the soda. When the Mentos is dropped into the soda, the ingredients used in the mint such as gelatin, break the soda's surface tension as it begins to dissolve. A Mentos mint also has thousands of "pits" and within these "pits" carbon dioxide bubbles can form as it makes contact with the soda. The Mentos sink to the bottom of the soda, carbon dioxide bubbles are created on the Mentos itself and gas is released. This causes the soda to be pushed up and eventually out of the bottle. A similar reaction happens when ice cream is dropped into a glass of root beer.

The Mentos Experiment

The actual experiment is easy. All that is needed is a roll of Mentos and a two-liter bottle of soda. Place the bottle of soda in the center of a table, preferably outside to limit the clean-up. Open the bottle of soda and position the package of Mentos above the opening. Drop all of the Mentos into the bottle at the same time, which will result in a bigger reaction. Either diet or regular soda can be used, and the reaction will be the same.

Variations on the Mentos Experiment

Record the height of each geyser and try different variations to make the explosion even bigger.

The Mentos and soda experiment can be used in place of the traditional baking soda and vinegar volcano many children create for a science fair. Make the same volcano out of plaster as if baking soda and vinegar were being used. But instead of the baking soda solution, place a 12-ounce bottle of soda in the center of the volcano. Open the bottle carefully and position a roll of Mentos above the opening as in the outdoor experiment. A geyser or lava will result. Color the soda red for a more traditional lava effect.