Soap Propelled Boat



  • A piece of foam or cardboard (non-currogated)
  • A foil tray or bowl full of water
  • Liquid dish soap




  1. Cut the foam or cardboard into an irregular pentagon shape about 2 inches as shown below.

  1. Place the shape in the water.
  2. Place drops of soap behind the boat.
  3. 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.

Share This Post