By: Courtney Horvat, Gary Kleinschmidt, and Casey Kelby

Steve Spangler began the phenomenon when he appeared on 9 News in 2002 and again in 2005 Eepybird.com continued the trend when a video featuring Fritz Globe and Stephen Voltz recreated the eruption with multiple fountains mirroring the fountain display at the Bellagio in Las Vegas

Besides becoming an almost instant internet trend, it has also been seen on a variety of TV shows including Numb3ers, Bones, and Myth Busters Many websites feature Mentos and coke video contests Eepybird.com even provides step by step instructions (Thank you!) and sells merchandise World Record: 1,911 simultaneous geysers by students of Latvias School of Business Administration Turbia

When you drop the Mentos into the soda, the gelatin and gum Arabic from the dissolving candy break the surface tension. This disrupts the water mesh, so that it takes less work to expand and form new bubbles. Each Mentos candy has thousands of tiny pits all over the surface. These tiny pits are called nucleation sites - perfect places for carbon dioxide bubbles to form. As soon as the Mentos hit the soda, bubbles form all over the surface of the candy. Couple this with the fact that the Mentos candies are heavy and sink to the bottom of the bottle and you've got a double-whammy. When all this gas is released, it literally pushes all of the liquid up and out of the bottle in an incredible soda blast. (Steve Spangler Science)

We went out and bought 40 bottles of Sprite and 40 bottles of coke (16 oz), Then we bought a few 6-packs of Mentos rolls We made a stand out of scrap wood to angle the bottle at 45° from the horizontal to give the best trajectory and used a rubber band to fasten the bottle to the stand We made cartridges out of bottle caps with holes in them, and strung Mentos on fishing line to eliminate errors when dropping in the Mentos

Then we would place the bottle on the stand, quickly take off the cap, replace it with the cartridge and release the Mentos Then we would measure the furthest spray To measure weight, we measured the weight of the soda (weight of bottle minus weight of empty bottle, then compared it to weight of fluid in full bottle)

What Happens Next?

We wanted to see whether the Diet Coke and Mentos eruption would go farther than the Sprite and Mentos eruption, as stated on Eepybird.com Perrier, Coke, Sprite, Diet Coke. (Wikipedia)

Diet CokeSprite Mean Standard Deviation Min5636 Q Median Q Max IQR

We reject Ho because p-value at ×10 -7 is < α=0.05. We have sufficient evidence that the difference between the average of diet coke is greater than the average of sprite. Assumptions: 2 independent SRS assumed Normal population or n30 n=4030

We are 95% confident that the difference in the average spray distance of Diet Coke and Sprite is between and inches.

For our second experiment, we wanted to see if the eruption displaced half of all the liquid, so we weighed the liquid and tested our results…

Min: 5.4 Q1: 10.4 Med: 11.4 Q3: Max: 12.9 Mean: Std. Dev.: 1.753

We reject Ho because p-value at × is < α=0.05. We have sufficient evidence that the average difference of net weight after the eruption is not equal to half the original weight. Assumptions: 2 dependant SRS assumed (before and after) n30 n=4030

We are 95% confident that the average difference in the net weight of the liquid remaining in the bottles after eruption of Diet Coke and Mentos is between and fluid ounces.

Weather/ Temperature Heat as a factor in experiment: the warmer the better Wind Exact measurements Scale Measuring Spray Drilling/Threading Cracked some shell and lost some of nucleation sights Overspray under cap Not enough time to screw it on all the way Fishing line caught, hands in the way Shaken soda/CO 2 released between cap exchange Holes in cap caused angle in spray

Overall the project was fun and interesting with all the science behind it While we may have had errors and biases, we performed our experiment to the best of our ability We feel that our results are accurate and that our methods helped us to achieve our accuracy

Diet coke is the best soda to use out of the Sprite/Diet Coke test When doing a Diet Coke and Mentos experiment, the net weight loss will not equal half of all the weight