Diet Coke and Mentos

Understanding the Science Behind the Eruption

The Diet Coke and Mentos Eruption is probably the most well-known and popular experiments of modern times. It is a highly entertaining, easy experiment that can be performed by all, young and old. Kids and big kids at heart will enjoy the intense geyser caused by only two ingredients. Note, if you are planning on doing this experiment yourself to see it, make sure you do it outside, as it is guaranteed to make a mess.

So what is this experiment?

If you haven’t heard of the Diet Coke and Mentos Experiment, it is pretty simple. As the titlDiet Coke and Mentos EruptionCredit: http://www.wikipedia.come suggests, you only need two things: a bottle of Diet Coke and a packet of Mentos. As mentioned above, you will also need a large area, preferably outside, as there is a high degree of mess.

Set up the Diet Coke bottle upright and unscrew the lid. You will need about half the packet of Mentos. Drop the Mentos at the same time into the top part of the Diet Coke. It can be tricky, so it might be best to use a funnel or tube to help.

Then comes the fun part, once you have dropped the Mentos into the Diet Coke, run like mad! What should happen is a huge eruption of Diet Coke should come jetting out the top of the bottle. The record for the geyser eruption is about 9 metres (29 feet) high. It is an impressive sight, one that will warrant another turn, so make sure you have more Diet Coke bottles and Mentos packets on hand, as it is an experiment that never gets old.

As you can see in the below video, if you have enough time and patience, you really can take this experiment to the extreme:

So what’s the science?

This experiment can work with other sodas and fizzy drinks, but Diet Coke has been proven to work the best because of the slightly different ingredients, and that it is slightly less sticky.

There are a few theories as to how this experiment works, but the most widely accepted one that is it is due to the combination of the carbon dioxide in the Diet Coke and the tiny little pores found on the surface of the Mentos.

Diet Coke, or soda and fizzy drinks in general, is pumped full of carbon dioxide when they bottle the drink at the factory, which makes the drink bubbly and fizzy. The carbon dioxide doesn’t get released until you open the lid, shake the bottle, or pour it into a glass. This means that there is a lot
of carbon dioxide gas built up within the bottle.

The pores on the Mentos increase the surface area available to cause a reaction with the carbon dioxide. This causes carbon dioxide bubbles to form rapidly and in such high amounts that it causes the eruption out of the top of the Diet Coke bottle.

In the video below, the boys from Mythbusters explore and explain this experiment further: