Gushing Soda Geyser

Most people have heard of the fabulously impressive Mentos and Diet Coke experiment before. If you haven't though, you're in for a treat.

This is a must-do for all kids who think science is boring.

What You Need
A roll of Mentos candies (mint flavor)
2-liter of Diet Coke
Piece of office paper
tape (optional)
someplace where it's okay to make a sticky mess (in other words, outdoors)

What to Do
Roll the paper into a tube the width of the Mentos. Add tape if desired. Load the Mentos candies inside the tube and hold the bottom of the tube so they don't spill out.

Open your 2-liter of diet coke and place it outside on level ground. Hold the tube of Mentos over the opening in the bottle. Quickly release your fingers so the candies slide into the bottle. BACK AWAY QUICKLY!!!

A gushing geyser of soda will come spewing out the bottle.

What Happens
That bubbly fizz that makes soda so yummy is the result of invisible carbon dioxide in the drink. Add something to the bottle and you'll see the CO2 at work (check out our Diving & Rising Raisins Experiment for proof). In the raisins experiment, tiny CO2 bubbles attach themselves to the raisins we added to the clear soda. This bubbling is called nucleation.

When the Mentos, which are covered with TONS of tiny pits, are dropped into the Diet Coke, CO2 bubbles instantly form in all the pits as the candies sink to the bottom of the bottle. The bubbles quickly rise to the surface, causing an eruption of soda!

Want a more detailed explanation? Visit Steve Spangler's site for more info, video, etc.