If you hang around near a pond, you might see a bug skate across the water. How does it do that? The answer has to do with surface tension.

The water molecules on the top of the pond stick tightly together. This creates surface tension. Since bugs are very light, they can rest on top of the water without breaking the tension. It’s like they are standing on solid ground.

You can explore the power of surface tension with a paperclip. First, get a bowl of water. Next, put a small paper towel square on top of the water. Then, put a paperclip on top of the paper towel.

What will happen if you use a pencil to push the paper towel into the water and away from the paperclip? The paperclip should float! It floats because of the surface tension of the water. The water molecules are sticking together.

Now you can repeat the experiment. But this time, add some dish soap to the water and stir. Then put the paper towel and paperclip on top. What happens when you push the paper towel away this time?

Most likely the paperclip will not float. The soap has caused the water molecules not to stick together as tightly. It has interrupted the surface tension. Because the surface tension is lower, the paperclip will sink.

You can also repeat the experiment with something heavier than a paperclip. You can test different items to see how heavy they can be before they break the tension and sink to the bottom of the bowl. Will two paperclips float? How about an eraser? Try it and see!