Fizzy eruption gets kids into science

A scientist at The University of Manchester is taking her own version of the latest Internet sensation into schools, in a bid to stir up interest in chemistry.

Mentos and diet coke make for an eruptive combination

The Coke and Mentos fountain experiment - which shows hundreds of large bottles of Diet Coke erupting when the sweets are added – has grabbed worldwide attention, inspiring many copycat experiments.

Dr Sarah Heath, who is Outreach Director for the School of Chemistry at The University of Manchester, is planning to incorporate the fizzy experiment in her demonstrations of science in schools throughout the Greater Manchester area. 

She said: “I think it’s a great thing because it’s got children interested in science. We can talk about the chemistry that lies behind it later, but the important thing is to capture their attention in the first place.”

There are several theories put forward to explain the reaction. Some have suggested that the gelatin and gum from the dissolving sweets break the surface tension of the liquid allowing bubbles of carbon dioxide to expand easier. However, but Dr Heath feels the rough surface of the sweets plays a big part.

“When you look at a Mento under a microscope you will see that it’s quite pitted and therefore has lots of nucleation sites, which causes the carbon dioxide to be released. There is probably also a chemical reaction occurring but there is a lot of debate about this.”

On the subject of what would happen to someone who drank Diet Coke and then ate Mentos, Dr Heath says: “When you open a bottle of Coke and drink it, most of the gas escapes so the reaction would not be as violent. But you might find that you burped more than usual.”

See the fountain of coke here:
http://eepybird.com/exp214.html