STEM Bouyancy:

Book: WHO SANK THE BOAT? Pamela Allen

Songs: “ROW, ROW, ROW Your Boat” and “A Sailor went to See See See"

Key Concepts: Buoyancy, Hydrophobic materials, boat construction and mass.


When a boat floats, it settles into the water, pushing the water aside to make room for itself. The force that it is pushing the boat into the water is called gravity. It is a two way pushing match, however. Water pushes back onto the bottom of the boat. This force, called buoyancy holds the boat out of the water. The more water a boat pushes aside, the more force there will be pushing back on the boat and supporting it. This is why a boat’s size and shape makes such a difference in how much of a load it can carry without sinking.


Materials: foil, coins, water in a container.

  • Design a boat out from the tin foil.
  • Predict how many coins it will hold when floating on water.
  • Test you prediction. Make sure you observe what happened when your boat sank.
  • Adjust your design based on what you observed, then repeat steps 2 and 3.

Rules: Your resources are limited! Be wise in what you use.