Kids Science Experiments

Toothpick Swimming

Did you know toothpicks could swim? Almost as good as synchronized swimming that you see on television (when all the people in a pool swim the same way at the same time).

Our Science Experiment

We are going to make toothpicks swim back and forth in a bowl.

What you need

a small square piece of soap
a cube of sugar
a bowl of water
5 toothpicks

How to perform this experiment

In your bowl of water, let five toothpicks float around in a circle with each point facing the middle of the bowl. Put a cube of sugar right in the center of the bowl. Watch what they do! Now empty the bowl and fill it with water again. Arrange the toothpicks in a circle again, facing the middle of the bowl. This time, put in the square of soap right in the middle.

Watch!

The sugar made the toothpicks swim to the center of the bowl. The soap made the toothpicks swim to the outer edge of the bowl.

Why did it do that?

When you put in the sugar cube, it was absorbing (sucking up) the water, which created a small current to carry the toothpicks towards it. The soap was releasing an oily film that spread outwards, carrying the toothpicks to the outer edge of the bowl.

I wonder what would happen if

I wonder what would happen if I used salt water rather than fresh water?