Science Bite - Gravity Boat

 gravity boats big banner

 

Make your own boat and see if you can sail it across your bath or an outdoor pool!  Learn about the forces acting upon it including gravity.


Remember - If you are trying these experiments at home you will need the supervision of an adult.

What you will need per boat:

gravity boats materials
  • 2 paper plates
  • A Polystyrene cup
  • A straw
  • A pencil
  • Scissors
  • Glue
  • Stickers for decoration
  • A bath or small pool

    • Instructions

    gravity boats 1

    Step 1


    Take two paper plates and glue them together, set aside to let them dry.

    gravity boats 2

    Step 2


    Use a pencil to make a small hole in the side of the disposable cup 2 cm from its base. The hole should be just large enough to push the straw through.

    gravity boats 3

    Step 3


    Apply a liberal amount of glue to the bottom of the cup and then stick it down to the centre of the top plate. Make sure the exposed end of the straw is longer than the edge of the plate.

    gravity boats sailing

    Step 4


    Your boat is nearly finished, it just needs some decorations. Apply stickers to the outside of the cup and give your ship a name. Now place your boat in a small bath or pool and fill its cup carefully until half full with water. Watch as your boat happily sails off, propelled by the water from the straw.

    Why does this happen?


    Forces that enable us to move are basically pushes and pulls. When we fill the cup on our boat with water, gravity pulls the water down through the straw and out into the tub or pool. As the water moves out of the straw, it collects behind the boat. As this collection grows it pushes against the boat, moving it forward.