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Floating a Paperclip

This Science Minute was researched and written by Cheyenne S. of Ithaca, NY.

Did you know that you can float a paper clip on water? This is because water has a kind of "skin" that is strong enough to keep the paper clip from sinking. This "skin" is actually surface tension, which is caused by the attraction of water molecules to each other. Some insects take advantage of surface tension to walk on water!

You can try a surface tension experiment at home. To make a paper clip float on water, you'll need a cup, a small piece of paper towel, and a paper clip. Fill the cup with water and lay a small piece of paper towel on the surface. Then, gently place the paper clip on top of it. After awhile, the paper towel will sink to the bottom of the cup and the paper clip will remain floating on the water–thanks to surface tension!

To break the surface tension, add a drop of dishwashing detergent to the cup. The detergent will weaken the attraction among the water molecules, and the paper clip will sink.