Science Project
by Kade Ramsay
Mrs. Majors, 6th Grade Science

Question:  Which soda drink will create the highest geyser when Mentos is added? Why?

Research:  All soda drinks are basically sugar (or diet sweetener), flavoring, water, and preservatives.  They are also carbonated (has bubbles), which means they have carbon dioxide gas.  The gas is trapped in the soda can or bottle.  Water molecules attach themselves to each other and do not let bubbles to expand. The molecules make what is called a "surface tension". If the molecules have to move apart, the bubbles can get bigger.

Hypothesis:  The soft drink with the highest amount of sugar will create the highest explosion.

Experiment:  Homemade Geyser

Materials:  Coca Cola 1.25 liters, Diet Dr. Pepper 1.25 liters, Sprite 1.25 liters, 3 packages of Mentos, Cardboard, PVC pipe tube, Measurement Tool


1.  Create a measurement tool on a wall.

2.  Put a piece of cardboard over the top of a newly opened soda.

3.  Place a PVC pipe with Mentos over the cardboard.

4.  Slowly remove the cardboard and let 5-7 Mentos fall into the soda bottle.

5.  Back away and measure the geyser.

Coca Cola and Sprite barely shoot to one foot.


Analysis:  When the Mentos candy hits the soda there is a reaction. The water molecules move, and the gas bubbles are able to get bigger, so there is an explosion of soda pop.  The diet soda has a larger explosion.  

Conclusion:  The only reason I think this happens is because it does not have real sugar.  It has aspartame, an artificial sweetener.  So, my hypothesis would be incorrect.  It was the soda with no sugar.  Maybe the sugar did not allow the water molecules to move as fast?