Aluminum Foil Boats


In this experiment we will explore the concepts of Archimedes principle of buoyancy.


  • 6 “ x 6”square of aluminum foil
  • Miscellaneous coins for cargo
  • Large bowl of water


  1. Construct a boat from the square of aluminum foil that will carry the most weight.
  2. Place the aluminum foil boat in the bowl of water.
  3. Add coins to the boat one at a time until the boat sinks.
  4. Using a scale, measure the weight of the cargo held by the boat before it sank.

Watch out!

Put warnings here.


  • Archimedes Principle states that the buoyant force upward on an immersed object is equal to the weight of the fluid displaced by the object.
    • Density= mass / volume
    • Weight of the object (downward)= mass of object * gravity
    • Buoyant force (upward)= volume of displaced fluid * density of fluid * gravity
  • Objects will float if the buoyant force upward is greater than the weight of the object.
  • The buoyant force upward is related to the volume of water that the boat displaces; as the water displacement increases, so does the buoyant force.
  • Once the weight of the boat + cargo becomes equal to the weight of the displaced water, the boat sinks
  • If an aluminum foil boat and a tightly folded piece of aluminum foil were both placed in water, boat would float and foil would sink even though they weigh the same. Boat displaces enough water to create buoyant force upward, whereas the piece of aluminum displaces very little water so no buoyant force up.