Theory Thursaday: Separating Colors

This is a super simple experiment to teach color combinations. The set-up is easy, but the results are pretty impressive. 

 You'll need a glass with an inch of water, a strip of paper towel, and a green marker. A ruler is optional.

Measure or estimate 2 inches on the paper towel strip.

Color a big blob on the paper towel (at the 2 inch mark) with the green marker.

 Stick just the bottom of the paper towel into the water in the glass for 20 minutes.

This is what ours looked like after the 20-minute mark. Not quite was it was supposed to. We left it sit overnight.

Much better! As the water rises up the paper towel, it dissolves the green spot and gradually moves the color up the strip of paper.  Since the colors that make up green - blue and yellow - do not move at the same rate, they separate, leaving a blue mark where the green was and yellow above that.

We discussed what would happen if we used different colors of markers. It was good secondary color review for Jake and Alyssa. They thought it was so cool to see the change. Jake had guessed that the green was going to spread all across the paper towel. He was right in that the color did spread. Pretty smart kid. He must have a good teacher. {wink}

* This experiment is similar to the leaf chromatography we did. This one was a bit more exciting to the kids though since it was a bit more dramatic. And not as stinky.