We tried to make a Mentos geyser again-and it worked! (Last time we tried it with 7-UP and had less-than-spectacular results.)  Here’s the (very short) video of our experiment and how to make your own Mentos geyser.  I can see why this is many people’s favorite science experiment ever!

If you want to try this experiment, you’ll need a two liter bottle of Diet Coke, a roll of  Mentos mints and a piece of paper.  Remove the lid from the soda and set it on a flat surface (outside!)  Roll the paper so it will fit into the mouth of the bottle and fill it with the Mentos.  Quickly dump the mints into the bottle and stand back.  Hopefully, you’ll see a huge gyser of soda shoot up from the mouth of the bottle!

Scientists aren’t sure exactly why the Mentos cause such an explosive reaction, but they think it has to do with chemicals in the Mentos breaking the surface tension at the same time that carbon dioxide (CO2) bubbles form on the surface of the mints, causing a huge, very fast release of carbon dioxide bubbles.

Here’s a funny video you won’t want to miss of a car running on the power of the Diet Coke/Mentos reaction.

Sometimes experiments work and sometimes they don’t.  The kids have been begging me to do the “Soda Geyser” experiment with Menthos for as long as I can remember, so we finally tried it on day 5 of Science Camp.

It was a flop.

We did everything right, as far as I could tell, but we used 7-UP instead of Diet Coke, since that’s what I had on hand.  Some scientists think the artificial sweetener in Diet Coke helps create a more violent reaction.  I’m not sure, but all we got when we dumped the Menthos into the soda was a very small geyser.  Let’s just say I felt really silly for yelling at the kids to stand back.

We’ll try again soon with Diet Coke and I expect we’ll have better results.

If you want to try this experiment, you’ll need a two liter bottle of Diet Coke, a roll of Menthos mints and a piece of paper.

Remove the lid from the soda and set it on a flat surface (outside!)  Roll the paper so it will fit into the mouth of the bottle and fill it with the Menthos.  Quickly dump the mints into the bottle and stand back.  Hopefully, you’ll see a huge gyser of soda shoot up from the mouth of the bottle!

Scientists aren’t sure exactly why the Menthos cause such an explosive reaction, but they think it has to do with chemicals in the Menthos breaking the surface tension at the same time that carbon dioxide (CO2) bubbles form on the surface of the mints, causing a huge, very fast release of carbon dioxide bubbles.

Try it and let me know how it works!