Sticky fun for the Fourth of July

It's all over the Internet. It's on David Letterman and the Today Show. It's on NPR, for Pete's sake. Across the country, people are caught up in a frenzy of extreme Diet Coke and Mentos experiments.

Want to try it at home?

Get permission, go outside, and have a hose handy. Things are gonna get messy...

  1. The simplest thing is to just drop a Mentos or two into a small bottle of Diet Coke.
  2. Not so satisfying? OK, now it's time to get serious.
  3. Make a "cartridge" of Mentos. Hold each candy with a pair of pliers, and carefully drill a small hole through the center. Then string five or six Mentos onto a straightened paper clip or a piece of fishing line.
  4. Hold the bottle cap with a pair of pliers and drill a hole through the top. (Start with a hole 1/4" in diameter.) Thread the paper clip or fishing line with the Mentos cartridge through the bottle cap so that the candy will hang down inside the bottle when you screw on the cap. Different sized holes in the cap will yield different effects.
  5. You can also carefully drill holes in the bottle, above the level of the soda. If you drill a ring of holes, you get a pretty neat effect. And you'll also make a super big mess.

Of course, you don't have to use Mentos and Diet Coke. The good folks at EepyBird.com have done many, many experiments, and it turns out that dropping just about anything into any kind of soda creates at least a little fizz. But Mentos and Diet Coke is an especially satisfying combination.

So how does it work?
The explosive effect is caused when the carbon dioxide that's been compressed in the soda escapes so quickly that the pressure pushes the soda out of the bottle. That's the easy part. But why do Mentos, in particular, cause such a good effect?

Part of the answer has to do with nucleation sites. "Huh?" you ask. Yeah, me, too. Soda is a liquid supersaturated with carbon dioxide gas, and nucleation sites are places where the carbon dioxide can make bubbles. A nucleation site can be a scratch on a surface, a speck of dust, or any place where you have a high surface area relative to volume.

Bubbles in soda: (Photo courtesy Spiff, Wikipedia Commons)
Bubbles in soda: (Photo courtesy Spiff, Wikipedia Commons)Courtesy Spiff

And Mentos have a lot of nucleation sites. There are lots of imperfections in their surfaces, and that allows lots and lots of bubbles to form. Plus, Mentos are heavy enough to sink when you drop them in, so they react to with the soda all the way to the bottom of the container. The sticky result is a fun, foaming mess.

But what happens if you drink Diet Coke and eat Mentos at the same time?
The EepyBird website has the answer, if you really must know...

Your Comments, Thoughts, Questions, Ideas

Thor's picture
Thor says:

I saw the Letterman episode where they were doing this....it was great. I'm going to try this sometime over the weekend. It reminds me a lot of Old Faithful out in Yellowstone and also the fountains at the Bellagio Casino in Vegas. BTW: You can learn a lot of neat science watching Letterman between the weekly "Will It Float" contests, the periodic visits of kid scientists and other odd stunts that they like to do. I think it's all a carryover from Dave's early days as a weatherman.

posted on Fri, 06/30/2006 - 2:39pm
Liza's picture
Liza says:

Scientific American's blog did a post about this.

posted on Mon, 07/10/2006 - 3:16pm
Liza's picture
Liza says:

CNN Money reported today that the makers of the mentos/diet coke video have made $28,000 so far selling ad space around the footage.

posted on Fri, 07/14/2006 - 11:30am
Rachel ^_^'s picture
Rachel ^_^ says:

Hmmm...looks really interesting!
I might need to try that at home!

posted on Fri, 07/14/2006 - 12:04pm
Anonymous's picture
Anonymous says:

Wow really? How intersting! Ill try into this!

posted on Fri, 07/14/2006 - 12:24pm
katie stillwell's picture
katie stillwell says:

i think the science musseum is a great place to learn and experment

posted on Fri, 07/14/2006 - 1:08pm
Joe's picture
Joe says:

I did this a couple of weekends ago. I got totally covered in Diet Pepsi (it was on sale, sorry Coke) as I didn't get the cap back on the bottle fast enough to get the spray to come out my drilled hole. The back spray coated me - much to the delight of everyone around me. This is totally fun and I would encourage everyone to try it!

posted on Mon, 08/28/2006 - 2:49pm
Marla Y  Valdez's picture
Marla Y Valdez says:

How does the explosion work?

posted on Tue, 11/14/2006 - 6:59pm
AzSha1's picture
AzSha1 says:

How cool

posted on Fri, 12/14/2007 - 11:07am
Anonymous's picture
Anonymous says:

if you put some thing really different in the pop how come it wont to the same thing as mentos? how do you know what has nucleation sites in it?

posted on Mon, 12/17/2007 - 7:39pm
Anonymous's picture
Anonymous says:

wat in the world do people need alot of candy for

posted on Thu, 05/22/2008 - 7:34am
Gene's picture
Gene says:

And now, in zero gravity.

posted on Sun, 08/31/2008 - 6:34pm
Anonymous's picture
Anonymous says:

Love the menots diet coke experiment. Did it with my 4 year old this weekend and explained what a chemical reaction and how a volcano erupts. He was digging bigtime. We found another cool site with fun science experiments to do. Will post
the link below for anyone interested.


posted on Fri, 11/28/2008 - 11:21pm
Lakotia's picture
Lakotia says:

i think that it would be cool if you did a rocket out of it.

posted on Sat, 11/29/2008 - 3:33pm

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