Engineer It! at home

Float Your Boat

Background Knowledge

Can you change the shape of tin foil to make it float?

How many pennies (or pebbles) can you keep afloat on your foil boat?

Suggested Materials:

  • Aluminum foil (1x 12” x 12” square per boat)
  • Pennies or pebbles

*To explore displacement, fill a cup all the way to the very top. Then drop in an object that sinks! The water that spills out of the top of the cup is displaced. If you want to learn more, try investigating buoyancy and density.

STEM Concepts: Boats can only float if they weigh less than the amount of water that they displace, or push away. Bigger boats can displace more water than smaller boats.

Extensions: What shapes of boats work the best? Can you build a boat out of different materials?

THE ENGINEERING DESIGN PROCESS

Define the Challenge: Design a tin foil boat and see how many pennies or pebbles it can carry.

Plan Your Design: What shape are boats usually? Which boat shape do you think displaces the most water?

Create a Prototype: A prototype is like a first try – see if you can build what you imagined.

Test Your Creation: Did your boat float on its own? How many pennies or pebbles could you add before it sank? What changes did you see as you added more weight?

Improve Your Design: Make changes to your boat so that it will hold even more pennies. Test out different shapes and sizes – could you try making it taller? Wider?