How to Make a Mentos Trigger Device

If you thought the original Mentos

If you thought that the original Mentos & Diet Coke Experiment was a mess, wait until you try this method. You'll have streams of soda flying in all directions thanks to a few pipe cleaners, a drill, and a few billion bubbles of carbon dioxide trying to make a quick escape.

Experiment Materials

  • 2-liter bottle of Diet Coke
  • 4 Mentos (those delightful mint candies)
  • Towel and/or a mop (by now, you know how useful these can be)
  • Electric drill or large nail
  • Pipe cleaner, dental floss, or thread and a needle

Experiment

  1. Carefully open the bottle of Diet Coke so it doesn't fizz too much.
  2. Have an adult drill a hole (the width of a pencil) in the top of the plastic 2-liter bottle cap. If you don't have an electric drill, punch a hole in the cap with a large screw or nail.
  3. This next step can be a little tricky. You'll need to put a hole through each of the Mentos just big enough to thread the pipe cleaner.
  4. Bend the end of the pipe cleaner to keep the Mentos from falling off. Thread the other end of the pipe cleaner through each of the Mentos.
  5. Thread the free end of the pipe cleaner through the bottom of the bottle cap and pull the Mentos tightly against the cap. Bend the end of the pipe cleaner at the point where it comes out of the cap so the Mentos stay in position. It's best to cut the pipe cleaner so that only an inch or so is poking out of the bottle cap.
  6. This step is often overlooked… find a large space in the middle of an abandoned field before you move on to the final step. Time for crowd control! Warn the spectators to stand back.
  7. Very carefully, replace the cap on the top of the 2-liter bottle and tighten it. Make sure that the Mentos are still tucked snugly into the cap so they don't touch the surface of the diet soda.
  8. When you're ready to create the soda geyser, straighten the bend in the pipe cleaner and push it down into the bottle (quickly!). When the Mentos hit the soda, you're in for an incredible show! The bottle shoots like a fire hose because of the restriction of the smaller hole.

Mentos Practical Joke

This little gem creates a squirting bottle of soda the moment anyone opens the bottle… and you don't need to drill any holes in the cap!

  1. You'll need a piece of dental floss, a needle, and some adult supervision (unless you're already an adult and then you need a kid to play the practical joke on).
  2. Thread the dental floss (or thread) through the needle and poke it through the middle of a Mento (the singular form of Mentos). Okay, thread two Mentos if you like (makes it easier to say).
  3. Tie the dental floss tightly around the Mentos, leaving one end of the dental floss free.
  4. Lower the Mentos tied to the dental floss into the bottle, but don't let them touch the soda. You just want them to hang in the neck of the bottle as close to the top as possible.
  5. While holding the string in one hand, twist on the cap. Trim the remaining thread that hangs outside the bottle.
  6. The bottle is set and ready to be opened by some unsuspecting test subject. When the cap is twisted open, the Mentos will fall into the soda and there's no stopping the geyser reaction.
  7. Okay, let's make sure that we stress responsibility. This reaction is going to make a huge mess and that's your responsibility (according to the rules of engagement).

How Does It Work?

The reason why Mentos cause such a violent eruption in Diet Coke is two fold – tiny pits on the surface of the candy and the weight of the candy. Each Mentos candy has thousands of tiny pits all over the surface. These tiny pits act as nucleation sites – perfect places for carbon dioxide bubbles to form. As soon as the Mentos hit the soda, bubbles form all over the surface of the candy and then quickly rise to the surface of the liquid. Couple this with the fact that the Mentos candies are heavy and sink to the bottom of the bottle and you've got a double-whammy. When all this gas is released, it literally pushes all of the liquid up and out of the bottle in an incredible soda blast!

Additional Info

If making this trigger device proves to be too difficult or the release of the Mentos is too unpredictable, check out Steve Spangler's Mentos® Geyser Tube.  The Geyser Tube allows for a perfect drop every time!

For a complete discussion of the science behind the gusher, read the Mentos Diet Coke Geyser experiment or visit Steve's blog at www.stevespangler.com. Here you'll find the most detailed online discussion of the Mentos Experiment and other tips and tricks from people with too much time on their hands.

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