Use these simple methods and you'll easily get 30 foot plumes of soda flying into the air (without any special restriction device screwed to the top of the bottle) to the delight of any kid (or adult).
The BEST Diet Coke and Mentos Experiment!
Kids and teachers alike seem to really enjoy our School Program: "Science Asks Why", but it's always the last demonstration that gets them the most excited, and although I certainly did not invent the famous "Diet Coke & Mentos" experiment, I most definitely have perfected it, resulting in round, brown spots on the ceilings of many Rhode Island Elementary School Auditoriums. After the program, I'm almost always asked how I get this particular demonstration to work so well.
I'll skip over the science behind why this experiment works at all, and tell you the simple secrets to getting a great geyser every time. Use these simple methods and you'll easily get 30 foot plumes of soda flying into the air (without any special restriction device screwed to the top of the bottle) to the delight of any kid (or adult) who happens to be watching.
1. Use Diet Pepsi instead of Diet Coke. Odd, I realize, to perform the famous "Diet Coke & Mentos" experiment without Diet Coke. Truth be told, they both work - but I've used both extensively, and I consistently find Diet Pepsi to work just a little bit better - so why not use it instead?
2. Heat the Soda (without opening the bottle, of course). Get a nice big pitcher - a one gallon size is great - and put your unopened bottle of soda in. Then, fill the pitcher with the hottest water you can get to come out of your sink (DON'T heat water on the stove and use that, please! There's hot and then there's just too hot). Let that bottle sit in the hot water bath for a good twenty minutes and I guarantee maximum altitude.
3. Figure out a good, dependable delivery system to drop the Mentos into the bottle as quickly as possible. I use a Giant Test Tube (sometimes called a 'Baby Soda Bottle', but that's a whole different article). You might use one too, or you might use a rolled up piece of cardboard.
4. When you "blast off", do it from a table top, such as a picnic table. Or put the bottle of soda on top of a wall. Whatever, anything to get it launching from just a bit higher than the ground. Launching from the ground isn't bad, but if you want spectacular results, give yourself a height advantage! 3 feet higher is, after all, 3 feet higher! The more kids have to bend their necks to see the top of the plume, the cooler they will think you are.
© Hema and Eric Bulmer. All rights reserved.