Coke and Mentos drive new rocket car

Posted by Emma Woollacott

We're not sure about its green credentials, but this is one alternative car. Powered only by Coke and Mentos, it has an impressive 221-foot range.

The feat required 108 bottles of Coke Zero and 648 Mentos.

The car uses a piston mechanism: a six-foot long rod sits inside a six-foot long tube attached to each bottle of Coke Zero. When the Mentos drop into the soda, the pressure tries to push the rod out of the tube.

"All that power is pushing against a wall braced with 3,600 pounds of cement blocks," say the car's creators, Fritz Grobe and Stephen Voltz.

"So all the force is directed into moving the Coke Zero & Mentos Rocket Car forward. We get one big push for six feet, and then it’s all coasting from there."

The trick works with most forms of soda, apparently, but Coke Zero is particularly powerful. It works through a process called nucleation, whereby the carbon dioxide in the soda is attracted to the tiny bumps on the surface of the mints.

"There are so many microscopic nooks and crannies on the surface of a Mentos that an incredible number of bubbles will form around the Mentos when you drop it into a bottle of soda," say the boys.

"Since the Mentos are also heavy enough to sink, they react with the soda all the way to the bottom. The escaping bubbles quickly turn into a raging foam, and the pressure builds dramatically."

And they have an answer to the really big question - what happens if you drink soda and then eat Mentos?

"Well, a lot of the fizz goes away as you drink. Then when bubbles are released in your stomach, your stomach can expand a bit. And your stomach also has ways of, umm, releasing excess gas…" they say.

Watch the video, here. There's a 3D version there, too.