Posted By Jim Walker Warning: If you are one of those people who think this “chat” forum should be only for serious H&S issues, read no further, quickly move onto a thread requesting a quote from regulations. I half caught a news item where someone dropped “something” in a bottle of coke and the stuff gushed out in a most impressive fountain. Can anyone enlighten me? What’s the physics (or chemistry) behind it? Does cheap coke work or do you need the “real thing”. Although I am just inquisitive, I was thinking of using it as a (outside) demo about dangers of mixing two seemingly safe substances in my COSHH appreciation talks. Just thought - it would be good for demonstrating the stored energy in a pressure system as well.

Posted By Paul Bellis Apparently its Montos Mints http://www.bbc.co.uk/glo...entos_coke_feature.shtml wow Paul

Posted By Paul Bellis Sorry should have read Mentos a few sweets in a small bottle and the whole pack in a big one last time I drink coke and eat a load of mints -wondered where the wind came from! Paul

Posted By Pugwash The "fountains" are impressive but the "rockets" are even better. Please do not try this at home....!

Posted By Hilary Charlton Actually, at school the "thing" is to make a volcano with bicarb and vinegar and colouring and watch it go - this is homework. So, if you are a parent with children DO try this at home, but don't seal the top of the bottle!

Posted By Descarte Nice to see them wearing safety glasses BBC news story http://news.bbc.co.uk/2/hi/technology/5188482.stm

Posted By Rochelle Cartmell Another good one is take a half bottle of tomato ketchup - only the one in the squeezy tube, add some bicarb of soda and place back in cupboard. Then when someone comes to use it, stand well back otherwise you get covered in tomato sauce. Another tip is only do when outside! The results are hilarious depending on who the unfortunate person is shaking the bottle!

Posted By Jane Blunt This experiment is one of a whole raft that are done by the Chaos team, among others see http://www.chaosscience....ub/public_html/index.php where you will find a whole lot more, suitable for all ages. Coke, like other carbonated drinks, contains a lot of dissolved carbon dioxide and the makers have arranged it that there is more than normally dissolves in the liquid. Therefore when you take the top off, some of it escapes. You can cause this to happen very quickly by providing rough surfaces on which the bubbles may grow and that is the basis of many of these experiments. The other experiment relies on the fact that coke is very acidic (you don't notice because there is so much sugar in it). So if you drop bicarbonate of soda in it the acid will react with the bicarbonate and form carbon dioxide. So you can get a jet of coke from two different experiments, and for two different reasons. In either case, shaking the bottle will have a dramatic effect. I would not recommend trying to make 'bombs' out of modern PET drinks bottles, so DO NOT screw the top back on. Jane