Surface Tension
Properties of Matter

Foil Boat

At home for 11-14 14-16

M&M - Foil Boat

What you need

  • A piece of foil
  • Scissors
  • Washing-up liquid
  • A sink or bath


  1. Take your foil and cut a shape 4cm x 10cm. The shape should look like a house (or rectangle with a triangle on top) with the base of the house being the shortest side. From the base cut a slot with a circle on the top.
  2. Gently place your boat into a sink full of clean water.
  3. Carefully place a drop of washing-up liquid into the boat's hole.

Results and Explanation

The boat moves! Water molecules are attracted to each other, creating "surface tension". The soap disrupts the surface behind the boat but the molecules in front are still pulling together, so the boat is pulled forward.

These experiments have not been specifically safety tested for home use but we believe them to be safe if the instructions are followed. Adult supervision or direction is recommended as appropriate. All experiments are carried out at your own risk.

Surface Tension
can be analysed using the quantity Force
Limit Less Campaign

Support our manifesto for change

The IOP wants to support young people to fulfil their potential by doing physics. Please sign the manifesto today so that we can show our politicians there is widespread support for improving equity and inclusion across the education sector.

Sign today