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Toying with the Diet Coke and Mentos experiment

A science editor is marketing a toy that lets you re-create the fountain effect show in the famous YouTube video. Photos: 'Triggering' Mentos into a Coke bottle

Mom and Dad, better grab your slicker and mop. A new toy is being marketed for youngsters who want to duplicate the "science" experiment demonstrated in a now famous YouTube video.

The video, titled "The Diet Coke & Mentos Experiment," shows the video's creators unleashing a Bellagio-esque fountain by dropping Mentos candy into 2-liter bottles of Diet Coke. (We'll get to what causes the volatile reaction later.) The video to video-sharing sites YouTube and Revver.

Steve Spangler, a science editor for a Colorado TV station and a toy maker on the side, this week demonstrated his "Geyser Tube" at the Toy Fair in New York. His toy is a plastic tube that can hold nine Mentos candies. A pin holds the candy in place while the tube is screwed to the top of the soda bottle. The opposite end is a narrow opening that acts like a nozzle.

A string is attached to the pin and when pulled, the Mentos plop to the bottom of the bottle, triggering the reaction. The Geyser Tube retails for $4.95 and can be purchased online at

Spangler said he started performing the experiment on TV more than a decade ago--long before it showed up on YouTube. But he acknowledges YouTube's popularity won't hurt business.

"We don't have any relationship with YouTube" or the makers of the video, Spangler said. "But I couldn't be happier for those guys. Science is for everybody."

What causes the geyser effect with sodas is the subject of much debate, Spangler said. He believes it's a physical reaction that occurs when carbon dioxide bubbles form in the microscopic cracks and crannies found on the Mentos.

Here are some of Spangler's tips: Always use diet sodas because they aren't sticky. The reaction also works with Life Savers candy but not as well because they're too light. Mentos' weight makes them sink to the bottom, which forces more of the soda out of the container.

And most importantly, after pulling the string, don't forget to run.