Diet Coke & Mentos

This is another in a continuing series of physics/chemistry experiments you can try at home with little or no risk to yourself, your home or neighbors.

Just about everybody has heard of it. There are videos of the experiment all over the internet. The topic has even been discussed on the popular TV show Myth Busters. Diet Coke and Mentos. Two popular American products, both fairly tasty. But, when mixed together create a violent reaction of epic proportions. A soda geyser!

The Experiment:

Our team, has decided to find to optimal amount of Mentos to displace the most Diet coke. We are going to record the amount of diet coke displaced from their respective bottles using varying amounts of Mentos.

Background Info:

This Experiment is relevant to everyday life in the sense that the "Diet Coke and Mentos" videos posted all over the Internet have become incredibly popular. The people at EepyBird.com are the ones behind the craze, posting the video that started it all.

Question:

What number of Mentos need to be dropped into a bottle of Diet Coke in order to get the maximum amount of soda displaced?

Hypothesis:

We believed that because of the relatively small size of the bottle, the greatest amount of soda displaced would be achieved when 5-6 Mentos were dropped into it. We chose this amount because after watching numerous videos, this looked to be the most popular amount.

Research:

To figure out why the two products reacted in a geyser-like way, we researched (both by text and online), and found good explanations from The Encyclopedia of Earth and Physical Science, The McGraw-Hill Encyclopedia of Science and Technology, and Science and Technology Illustrated. We related these explanations to our experiment, figuring that if you use too few mentos, there would only be a minimal amount of "fizzing," displacing a small amount of soda. But if you added too many Mentos, the surface area for the bubbles to form on would be very large, and the carbon dioxide in the bottle would be used at a rapid rate, leaving little time for pressure to build in the bottle and displace soda.

THE EXPERIMENT

Independent Variable: # of Mentos

Dependent Variable: Diet Coke displaced (mL)

NOTE: To ensure accurate data, we made sure that all the bottles of soda were opened just before being tested, and we ensured that weather was not a factor in the experiment whatsoever.

The Materials:

12 bottles of Diet Coke (591ml each)

4 Packages of Mint Mentos

1 Graduated Cylinder (ml)

**Paper and tape

The Procedure:

1. Open up one bottle of your diet coke and place on a flat surface.

2. Open your box of mentos and take out two mints.

3. Drop the mints into the Diet Coke and stand back.**

4. Wait for the Coke to calm down.

5. Pour the remaining Diet Coke into a graduated cylinder.

6. Record

7. Repeat steps 1-6 two more times for a total of three trials.

8. Repeat steps 1-7 using different amounts of Mentos (4,6,8)

**When pouring 6-8 mentos into a diet coke at once, we found it helpful to construct a mentos dropping device by rolling a piece of paper into a tube. Just big enough to fit mentos through. This will make it a lot easier to drop all the Mentos in at once. If dropped one at a time, the reaction would not reach its peak performance.

Data:

Coke And Mentos
Amount Of Coke Displaced (ml)
# of Mentos	Trial 1	Trial 2	Trial 3	Average
2	353	354	367	358
4	404	398	356	386
6	376	371	376	374
8	365	360	374	366

Conclusions and Generalizations

When using more than four Mentos the amount of coke displaced decreased. This shows that four Mentos is the optimum amount to displace the most diet coke in a 591ml bottle. Four Mentos displaced an average of 386mL of Diet Coke while six and eight Mentos displaced 374mL and 366mL respectively.

If other teams were to approach the same experiment, they would more than likely achieve the same overall trend, and their results wouldn't be to far from ours. We believe this because we know that every Diet Coke bottle is made almost identical in the factory. We believe this to be the same with Mentos.

Another experiment that could be attempted regarding Diet Coke and Mentos is how much does the volume of coke affect the amount of coke displaced? This could be done by using a certain amount of Mentos per cubic ml.

Walter

Sources:

The Encyclopedia of Earth and Physical Science

The McGraw-Hill Encyclopedia of Science and Technology

Science and Technology Illustrated