Mentos Experiment

After having witnessed the video of the two guys dropping Mentos candy into 2-Liter Diet Cokes on eepybird.com, we couldn't resist trying the experiment at work on our smoke break.

For the first experiment, we didn't have a 2-Liter or a Diet Coke, so we used a 20oz Diet Pepsi. I devised a paper tube from an index card to fit over the neck of the bottom. Just above the opening, I cut a slit and put a piece of paper in there cross ways to hold the Mentos just over the fluid. Then, I yanked the paper out and took off running. The drink did indeed produce a lot of foam, but it wasn't nearly as exciting as the video. The foam came out and spilled over the sides without making any kind of geyser.

So we watched the video again to see what we did wrong. We realized in the video, the guys left the lid on. They drilled a hole through the lid and fed a string through it. This creates a nozzle of sorts. Then, they apparently threaded the Mentos onto a string. So on smoke break #2, we took the original bottle, filled it just above half-way with Diet Coke, and poked a small hole in the lid. We recreated the experiment pretty well. The hardest part was getting the needle through the Mentos without breaking them. I nearly made the mistake of putting the lid on before we went outside. That could have been a disasterous elevator ride, if I'd accidentally let go of the string.

Outside, I had Terry hold the thread and Mentos above the fluid while I put the lid on. Then we dropped the string and Mentos into the Coke. This time we created a geyser, but it still wasn't like the one on the video. Not even close. I think we had too much air in the bottle. By the time the foam bubbled up to the neck, most of the air pressure had already escaped. I think the bottle has to be filled up nearly to the top.

Maybe we'll try again tomorrow.