Go outside to the middle of a field, a huge lawn, or your garden
. Bring a roll or box of Mentos (candy mints) and a 2-liter bottle of soda. Either diet or regular soda works for this experiment, but diet soda erupts higher (soda can get sticky when you're cleaning it up).
Open the bottle of soda carefully
. Position the bottle on the ground so that it will not tip over.
Unwrap a whole Mentos roll
. The goal is to drop all of the Mentos into the soda bottle simultaneously (it's trickier than it sounds so put in one if you like). One method for doing this is to roll a piece of paper into a tube (like a cardboard toilet paper roll) just big enough to hold the Mentos. Put a card under the roll and on top of the bottle top, so you just pull off the card and the candies will all drop in at once. Alternatively, use scotch tape to wrap around the Mentos, making a stack.
Watch the soda eruption
. It's just like fireworks on the 4th of July. The spectators cheer in a chorus of oohs and ahhs!
To make a soda bottle spinner is basically the same as above except slightly more challenging
.The effect is you will place a bottle on the ground add mentos and it will spin around spraying cola everywhere.First get a 2 liter bottle of cola (diet is the best)poke a hole in the lid just big enough for you to drop mentos in.This next bit has the be done fast,use the same technique for dropping mentos as above (using a test tube or paper tube and card)after doing that in a spit second place the botttle on the ground and watch it spin(depending on how you have done it might propel backwards instead)The alternative is wrapping the mentos in sellotape leaving the top and bottom free of tape though,this will make it slower for the mentos to desolve thus giving you more time plus you can make a smaller hole.Enjoy and try to involve your friends by playing Speedy Spin,a game in which the player who's bottle lasts the longest wins.