Challenge kids to make a paperclip float on water. This simple task seems impossible until you understand the power of surface tension.

Supplies

• Clear glasses or cups of water
• A box of paperclip
• Paper Towels for clean up or spills

Setup Float a Paperclip on Water Challenge

Before the kids arrive get a paperclip to float on the top of the water.  Do this by bending a paperclip to make an L like shape. Place another paperclip on the horizontal portion of the L and lower it into the glass of water.  The paperclip should float.

How to Run the Challenge

Have the kids drop a paperclip into their cup, they will note that it sinks to the bottom.  Show the kids that you have defied the laws of physics by floating a paperclip on water. 

Explain that the top of the water is like a skin on the water.  The particles stick together, we call this surface tension. The surface tension allows the paperclip to defy physics, because paperclips sink, but with a steady hand you can get the paperclip to sit on top of the waters surface.

Challenge kids to find a way to get a paperclip to sit on water.  After a few minutes of kids trying to set the paperclip onto the water with their hands ask them to use another paperclip to make the original paperclip float. Guide them in their experimentation until they have a paperclip sitting on the surface of the water.

More Water Physics Activities

If you enjoy float a paperclip you may like the Tinfoil Boat Challenge. The Tinfoil Boats Challenge asks kids to build a boat that will float and will hold 100 pennies. You may also like Drops on a Penny, where children learn about water molecules while seeing how many drops of water they can get on the face of a penny.