Sticking M's

When I demonstrate candy experiments, floating M's are still one of the biggest crowd-pleasers. Apparently my four-year-old is also entranced by them, because she invented a new floating M's experiment by touching one of the floating M's with her finger:



Who knew you could actually pick them up?

Acid Test for Science Fair

Science fair project: use baking soda solution and purple cabbage indicator to compare candy acidity. Purple cabbage indicator (made by boiling, or soaking, purple cabbage in water) changes color based on pH. If you add a base, it turns blue, and if you add acid, it turns pink. Here's the original color.

First, we dissolved various candies in indicator. The brightest pink are the most acidic.

Then we added baking soda water to each sample to bring it to neutral, and compared how much soda we used for each sample to arrive at an acidity comparison.

One fun little thing: to dissolve the maximum amount of soda in water, we warmed the water up. As it cooled, the soda started to crystallize again. Apparently, our initial solution was a little supersaturated.

Airy Chocolate

This Reader's Digest snippet from 2011 describes how candy makers stretched out the cocoa by adding air: "The price of cocoa is soaring, and candy makers are stretching ingredients by adding air. They say the chocolate is creamier, with fewer calories." Wonder if they're still doing it, and wonder if you can tell the difference when you put the bars in water?

Of course, some chocolate bars are made with lots of air bubbles, like the British aero bar. We floated one once, and had it spinning in nice circles.

Here's a Businessweek article with more info.

Gummy Gecko Tails

One gecko went for a swim, and the other stayed dry. One gecko floated in water, showing off hidden air bubbles, and the other gecko kept its secrets. One gecko absorbed so much water it grew, and the other lay by the side of the pool. One gecko swam away (down the drain) and the other was forgotten in a bowl.

One gecko, sitting in a bowl for weeks, got its tail bent out of shape!

(For a few minutes, the tail stuck up at nearly a 45 degree angle. Sadly, after we placed it on a plate, gravity eventually took its course, and our gecko became flat once again.)

Multilingual Conversation Hearts

It shouldn't be a surprise that conversation hearts are made for other languages. But when I opened my new bag of hearts for experiments, it took me a moment to realize that 1) the messages were different than usual and 2) I could still understand some of them because they were in Spanish. Hola, amigo!

How many can you understand?

Easter Candy Diet Coke Fountain

I spent a whole afternoon trying different kinds of candy in Diet Coke geysers to see if anything could approach Mentos. I had OK luck with Sweethearts, and Sweet Tarts, which seem to have the right kind of surface (slightly pitted) but aren't heavy enough to drop immediately to the bottom of the bottle like Mentos do. Regular jelly beans were a failure--I think they're too smooth for the soda bubbles to form quickly on their surface. But one candy made me want to try again. Guess what we were doing all evening?

Here's are two nice Coke Zero geysers done with bumpy Nerd jelly beans.

Why do the bumpy Nerds create such a good geyser? My guess is that it's because they have a lot of extra surface area, because all those bumps stick out so much. That gives the soda bubbles even more space on which to form, and so the bubbles can form quickly.


So how do the bumpy Nerds compare to Mentos, geyser-wise? I tested Mentos, using the same amount of weight as I had with bumpy Nerds (10 g). Here was the result:
I had such high hopes, but the Mentos still won. This time.

By the way, when I used this experiment today I tried out the Steve Spangler Mentos Geyser Tube. (Steve Spangler is the person who popularized the Mentos/Diet Coke experiment in this video.) The tube works quite well, sending a fountain much higher than if you drop the Mentos in from a cardboard tube, and you're also far away from the mess so you're not nearly as likely to get Coke all over your clothes. Of course, there were drawbacks as well--once I forgot to screw the top on tightly, and the exploding soda pushed the tube right off of the bottle. Another time the bottle fell over when I pulled the trigger string (though this may be because I had to replace the pin, which I lost, with a nail which worked great except when it didn't). So, if you use the Steve Spangler tube, use it right and don't lose the pieces!

XKCD and Cadbury Eggs

XKCD has its own version of Find Hidden Candy, using Cadbury Eggs. (This work is licensed under a Creative Commons Attribution-NonCommercial 2.5 License.)