In this experiment/art project, you’ll be learning about why certain things float on water as you make a unique piece of art. Unfortunately, the art doesn’t last, but that’s what cameras are for!
Materials:
- Cinnamon (powdered, not sticks)
- Wide bowl or plate deep enough to pour water in
- Liquid soap
- Toothpick
Procedure:
- Fill a small bowl or a plate with some water. Not to the top, that’s hard to clean up!
Sprinkle some cinnamon on top of the water so that it covers the entire surface- Try taking the toothpick and drawing along the surface of the cinnamon. You should notice not much happens! Keep that in mind for what we do next.
- Dip one end of the toothpick in some liquid soap; not that the soap is dripping, you just want to coat the end in soap
- Now try to draw a line in the cinnamon! You should notice you are able to “cut” through the layer easily.
- Experiment with the patterns you can do!
Explanation:
You just learned what soap does to the surface of water! Water has a property called surface tension which forms a barrier that prevents certain things from falling through it – light things, not anything too heavy! That’s why the cinnamon floats on top so easily. When you try to draw with just the toothpick and no soap, the cinnamon stays clumped together and stays put on the water. However, when you add soap to it, it immediately cuts through the layer of cinnamon. It’s not actually doing anything to the cinnamon, the soap is lessening the effect of surface tension on the water. The cinnamon doesn’t want to be in those parts and gets pushed away. I particularly liked when you outline a chunk of cinnamon and it floats around like an island!
Going further:
Try other materials on the surface of water to see what soap does to it. Make sure to get fresh water before you try more stuff in the same bowl or it won’t work as well.
LOOKING FOR MORE science experiments? Find them here!
About the author:
Steve Davala has been teaching math and science to middle and high schoolers since 2000. He writes books, plays music, carves wood and he loves learning new things. Ask him a question at steve.davala@gmail.com.
