Mentos vs Diet Soda Science Fair Projects

Urban Legends

Urban legends can be fun to test in a science fair. One great legend to check is the one about Mentos and Diet Coke.

EDU-36820 C2D Discovery Planet Digital Microscope	Young Scientists Club Set 2	Discovery Planet EDU-41021 Maxscope Videoscope	Student, HomeSchool & Adult Microscopes
Ages 8 and up	Ages 5 - 8	Ages 10 and up	Age 10 thru College

Objectives/Goals

The purpose of my experiment was to discover if the type of soda used with Mentos would affect the height of the geyser.
My hypothesis was, "I believe that the type of soda will affect the height of the geyser, and I believe that the Diet Coke will make a higher geyser because I think that there are ingredients in the diet soda that will affect the Mentos strongly that could have the potential to cause a higher geyser".

Methods/Materials

Mentos, runs of 9 types of sodas (Cherry Coke, Diet Coke, Shasta Cola, Coke Zero, Diet Dr. Pepper, Co Cola Classic, Diet Shasta and Club Soda as a control, all in 2 liter plastic bottles of similar shapes), measuring tape, empty bottle, camera and stand, stop watch, notebook and microscope.

I controlled the variables as much as I could, with the only variable being the type of soda used in my experiment. I measured the height of each geyser and also photographed it to study later.

Results

There were a total of 18 valid geysers. The highest geyser, Diet Shasta, was 52" at its highest which was almost twice as high as Diet Coke's geyser, and 26 times higher than the lowest which was Shasta Club Soda. Therefore, because I thought that Diet Coke would be highest, my hypothosis was wrong.

Conclusions/Discussion

I think that the experiment concluded the way it did because there is something in the diet soda that makes the explosions go higher. It's probably because of the sweetener. Shasta uses Splenda and Diet Coke uses Aspertane. Coke Zero used a combination of artificial sweeteners and had a poor geyser. Companies keep the ingredients secret but I think Diet Shasta's success had something to do with Splenda as nearly all of the sodas had otherwise similar ingredients.

I would like to study nucleation and artificial sweeteners further. I'm really interested in how nucleation affects ice-cream floats. 3rd party contributor