Teaching ScienceHelp for trainee Science teachers

The Class of 09’s (almost) Organised Display of Diet Coke and Mentos….

The Science Bit can be found here.

Fancy going for the world record? Info here. 504 simultaneous geysers

(well the last word for now) Keep an eye on this website http://mentos.co.uk/fountaincompetition/ This year’s competition is closed but hopefully they’ll run it again.

For now, there are some fun videos in the Gallery section – maybe inspire you to try some displays of your own.

For an explaination of what is going in with the coke and the Mentos, here are three websites that may help

http://www.eepybird.com/science.html

http://www.sciencebuddies.com/science-fair-projects/project_ideas/MatlSci_p023.shtml?from=Home

http://antoine.frostburg.edu/chem/senese/101/consumer/faq/mentos.shtml

These chemists are saying that the primary cause is physical, not chemical.  Their explanation: nucleation sites. If you have a liquid that is supersaturated with gas (like soda, which is pumped full of carbon dioxide), a nucleation site is a place where the gas is able to form bubbles. Nucleation sites can be scratches on a surface or specks of dust – anywhere that you have a high surface area in a very small volume. That’s where bubbles can form.

Mentos seem to be loaded with nucleation sites. In other words, there are so many microscopic nooks and crannies on the surface of a Mento that an incredible number of bubbles will form when you drop it in a bottle of soda.  Since the Mentos are also heavy enough to sink, they react with the soda all the way to the bottom. The escaping bubbles quickly turn into a raging foam, and the pressure builds dramatically. Before you know it, you’ve got a big geyser happening!

From Eepybird website

Eepybird also has a link to a pdf file which gives a different launch mechanism for the Mentos mints. Worth a look.

The full video in all its glory

Diet coke and mentos from Danny Nicholson on Vimeo.

As streamed live onto the Internet via Qik.com

If you want to do your own Diet Coke and Mentos experiment, then you will need some kind of mechanism to allow you to release the mentos into the Coke from a safe distance.

You could probably cobble something together yourself, but one thing that you can buy is the Geyser Tube, which is available from gadget stores such as Firebox for about a fiver.

Put the mentos in the tube, then pull the string and stand back. The pin will pull out and release the mints into the Coke.

Try this as part of a Sc1 investigation – test different brands of cola, types of fizzy drink etc.