- A piece of foam or cardboard (non-currogated)
- A foil tray or bowl full of water
- Liquid dish soap
- Cut the foam or cardboard into an irregular pentagon shape about 2 inches as shown below.
- Place the shape in the water.
- Place drops of soap behind the boat.
- Watch the the boat move across the water! Congratulations! You made a soap powered boat!
Why does this work?
Soap breaks down the surface tension, the tension of the surface film of a liquid caused by the attraction of the particles in the surface layer, which propells the lightweight material across the surface. Soap is a surfactant, so this is why this works.