 |
|
 |
  
Demonstration no.: 122 Description: If you put a Mentos into a soda, you will get a very sudden and powerful eruption. When CO2 dissolved in soda forms bubbles, this does not happen in the middle of the liquid. The small CO2 bubble has to counteract the strong surface tension of the water, and for this to be possible, the bubble will preferably form at small impurities in the liquid or on the surface of the container. Similarly, one will only see CO2 bubbles from a glass of beer or a soft drink being formed at certain points on the inside of the glass, and if extraordinarily many bubbles form at the bottom of a glass of carbonated liquid, it is very possible that the glass is not completely clean. 
Coke and Mentos. Here, the Mentos are places in a graduated cylinder, but one can also use a tube folded from paper or cardboard.
There are many of these tiny crevices, in which the bubbles can be formed, on the surface of the rough Mentos, and this make them very efficient at releasing the carbon dioxide of the soda. In addition, the candy's content of gum arabic reduces the surface tension of water, making it even easier for the bubbles to form. 
A hole Mentos roll dropped into a soda.
Diet Coke is better than ordinay coke containing sugar. This is due to the surface tension of the aspartame containing diet product, which is lower than that of the sugar containg soda. Because of this, it is easier to form bubbles in diet soda. Another advantages of using diet soda is the fact that the liquid is less sticky, making it easier to clean up after the demonstration has been done! 
The Chemistry Show of Aarhus, Denmark, performing a show with Mentos and soda in 2006.
The Mentos candy can be dropped directly into an open coke bottle, but you can also make a device where the candy is placed on a string or similarly right below a hole in the lid. You then just have to pull the string to release the Mentos. The small hole in the lid will also increase the power of the jet. The Mentos and Diet Coke experiment has, in a very short time, become very popular, and on the internet (for instance on Google Video) many videos with the demonstration can be found. 
The Chemistry Show of Aarhus, Denmark, performing a show with Mentos and soda in 2006.
The reason for the popularity is “viral marketing“, where entertaining videos containing commercial products is spread like a kind of virus on the internet. If the video is fun, people will automatically forward it to their friends, and the companies behind the products in the video will get plenty of free advertisement. The Mentos demonstration was, however, not made as a viral campaign from neither the producers of Diet Coke nor Mentos, but the videos are so popular that the Mentos company estimates that they have a value of more than 10 million dollars! The demonstration has been known for some years, but it first became widely known in the public as a science experiment in American television in 2005. Steve Spangler performs entertaining physics and chemistry demonstration experiments in the morning show of 9NEWS. Steve describes the demonstration on his own webpage, and on the webpage of 9NEWS Steve's videos can be found (see the references). Steve's Mentos video were quickly spread on the net through blogs, and the demonstration has been featured on shows like Letterman, The Today Show and ABC's Good Morning America. Even Wall Street Journal has written about it. The demonstration was finally believed to be explained in the article by Tonya Coffey from 2008 (see the references). The most popular Mentos video currently is made by EepyBird.com ("Extreme Diet Coke & Mentos Experiment"), who has performed a great experiment with 200 litres of Diet Coke and more than 500 Mentos. The demonstration was posted on their website on June 3rd 2006, and in only one week the video was watched about 800,000 times. A variation of the demonstration is to put a whole roll of Mentos (still wrapped in the aluminum foil) into a coke bottle, which is then immediately sealed. The bottle is shaken lightly and soon becomes very hard due to the pressure. You then loosen the lid a bit, so the gas is just beginning to escape. Throw the bottle hard down on the ground. The lid will fly off, the coke is pushed out in a powerful jetbeam, and the bottle will fly far away as a rocket. Watch the videos of the demonstration on Google Video in the references.
Equipment and materials:
References:
PIRA DCS: 4C30.00 (Thermodynamics: Change of state) Updated: 16 June 2008 If you have comments, corrections or suggestions regarding this demonstration, |
Mentos and Diet Coke explosion
Note that the bottle flies away with great force. Try to be far from something that may break, and never throw the bottle, so that the lid is pointing away from you (the bottle will be flying towards you).
Large bottle of soda (Diet Coke or similar)
 |
| FYSIKBASEN.DK was updated on Sunday, 16 June 2008, at 23:01. |