Need a way to discourage your kids from drinking dark, sugary sodas? If you’re having a hard time convincing them that it’s no good for their teeth, look no further than this science experiment.

If your children are old enough to have lost baby teeth, then that’s truly the best material for the activity; just make sure you play before the Tooth Fairy pays a visit, or they’ll be confused!

At only 4, Travis hasn’t lost any teeth, so we needed another material that would tarnish in soda like tooth enamel. The online suggestion was… eggs!

That means I need a little caveat before the post, because now it sounds very vegan-unfriendly. We also needed a can of Coke, and one of Sprite, two sodas we wouldn’t actually be drinking in our household anyway. But in the name of science, the sodas were purchased, and eggs were borrowed from my mother-in-law!

With that vegan caveat out of the way, it was time to be scientists. We filled one glass with Coke and another with Sprite.

Travis was very curious about the eggs, so we checked them out before adding one to each cup.

He loved seeing the way the sodas bubbled. “And that would hurt my teeth!” he surmised. He’s onto something…

Then it was just a matter of waiting. We set up a chart, with a column for each soda and a row for each day we’d observe. This was a nice chance for Travis to practice writing his numbers.

Every day, we used a big spoon to scoop out the eggs and observe. You can definitely break out the magnifying glass each day, too.

The first thing he noticed was that the bubbles faded by Day 1. The eggs, however, had changed very little.

By Day 2 we wondered: was the Coke egg a little darker?

Finally by Day 4 it was obvious; the coke had tarnished one egg. (Hopefully Travis’s take-away is not that he should drink lots of clear soda!).

I reminded him that what we saw in the egg was similar to what we’d see in a tooth. So avoid sodas to avoid discoloration and decay.

Overall, we liked the STEM aspect of this project, but I think it would have been clearer for him with real teeth. Perhaps we’ll have to do it again when he loses his first!