An activity which demonstrates the action of a propeller
Sawers Boat - flat


  • A piece of stiff cardboard
  • A strong rubber band
  • Good quality cellophane tape or masking tape
  • Scissors
  • A tub half filled with water


  1. Cut the cardboard as shown
  2. Cut a smaller piece of cardboard that can fit in the back groove, as shown
  3. Tape the rubber band to this small piece of cardboard and the two back grooves of the boat
  4. Turn the centre strip so that the rubber band gets well twistedSawers Boat - Bottle
  5. Immediately release the boat into the tub of water and see how it moves forward
  6. Can the boat be made to move backwards?

Teacher’s Note
Discuss factors that help boats and ships to move in water (wind, water currents, manual power using oars, electrical power).

Explain the concept of how propellers of boats and ships push water backwards so that they can move forwards. The swimming action can also be discussed.

Ask the children to experiment with other paddlewheel propellers.