We think that it’s all to do with the science of bubble formation, believe it or not.
The surface of a Mentos mint appears to provide a highly efficient place for tiny bubbles to form (these places are known by the boffins as nucleation sites). When Mentos are dropped into Diet Coke, these bubbles form very rapidly. As a result, the carbonated part of the Diet Coke reacts explosively causing an eruption.
Did you know? For every litre of Diet Coke there are 4.3 litres of dissolved carbon dioxide gas. This gas escapes from the drink very quickly when Mentos are added to it.
Find out all the facts about Diet Coke.