Scientific progress goes Foosh!!!!

It’s time for another installment in the saga of Things-That-Go-Foosh!!!!

Taking a break from work last Friday, a few of my coworkers and I did an experiment with dropping three Mentos into a bottle of generic soda. All I did was to place the bottle on the pavement, take the lid off, and very quickly drop three Mentos mints through the opening.

The result was a stream of soda between four and four and a half feet high. Naturally, this led to more questions:

Does it have to be diet soda?
Does the brand make a difference?
What happens if you drink a soda while eating a Mentos?

To answer the first two questions, we did another experiment this Friday.

As far as drinking a soda while eating Mentos, there’s a video on Google on that subject

This time out, I did a bit more prep work.

I wanted to get a bit more “pizzazz” out of the experiment, instead of just having the soda bubble up to around 5 feet, I wanted to get some height from it. So the first bit of prep work was to drill a 29/64″ hole in a bottle top. That’s actually quite a bit harder than it sounds because the drill wants to hang up on the plastic and twist it away from you. You’ll probably want to use a pair of pliers, put the cap upside down on a piece of scrap wood, and still be careful.

Next, dropping the Mentos into the soda is tricky at best. Wait too long to drop the next mint and the soda’s already bubbling up at you! And with the smaller hole in the bottle top, you need to be able to put the Mentos into the bottle and not have them drop in until the bottle cap is in place.

My solution was to drill a hole through all the Mentos I was planning to use, thread a wire tie through groups of four, and put the wire tie through the bottle cap, letting go when I was ready to start the fountain. This worked out pretty well, though I did make two important discoveries in the process:

Mentos have a gum-like center. This is the source of the mint scent you’ll notice when drilling holes through them. (A small drill bit is the way to go so you don’t loose too much of the surface. 7/64″ seems to be pretty good.)

The stuff in the center of a Mentos will tend to stick to the drill bit. (I had a fair amount of success at cleaning up by running the drill through a piece of scrap wood afterward.)

Finally, I gathered a variety of soft drinks in order to test whether the brand of soft drink mattered as well as the differences between the regular and diet versions. In all I ended up with five bottles: generic diet soda, Pepsi, Diet Pepsi, Coke and Diet Coke.

Once all the materials were put together, the next step was to gather up a few coworkers. Fortunately, word of the previous week’s experiment had already got around, so it wasn’t too difficult to find a few people who wanted to see what would happen.

The first bottle “launched” was the generic soda. This was impressive! The bottle I’d launched the previous week was also generic diet soda and the soda stream went about four and a half feet. This time, using the bottle cap with a hole in it, the stream went up about ten feet. Quite cool.

Next up was the Diet Pepsi. Take the cap off the previous bottle, set up the Mentos, put the cap in place, drop the Mentos, and FOOSH! Granted, it’s a very small sample set, but brand name versus generic does make a difference. The Diet Pepsi went about a foot higher than the generic.

Next came the regular Pepsi. My guess is that the regular soft drink has a higher density than the diet one because of the sugar. Whatever the reason, the regular Pepsi only went up around eight feet.

The next to last bottle was the regular Coke. This one was the big surprise. A week earlier, the bottle of generic soda with no cap shot up about a bit more than four feet. Even with the drilled cap on it, the regular Coke barely reached five feet.

Because the video I’d first seen involved dropping Mentos into Diet Coke, I saved that one for last. It was quite the spectacular ending. One of the theories on why Diet Coke goes so high is that it has more carbonation than the other soft drinks. More carbonation = more bubbles = a higher spray. Whatever the reason, the Diet Coke went highest, somewhere around twelve feet.

The reason for doing this series of experiments was to answer the questions about whether the brand of soda makes a difference – it apparently does – and how significant the difference is between regular and diet – quite the huge difference for Coke and Diet Coke.

I suppose some folks think this is a waste of soda. Perhaps it is. But laughing as the soda goes spraying into the air has got to be better for you than actually drinking the stuff. 🙂