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You Need

1 ‘boat’ (an aluminum mini tart pan, 6.4 cm x 2.1 cm)

A large collection of pennies (or washers, as in the photograph)

1 large container of water in which to float the boat

Try This!

1. Place the empty ‘boat’ in water, and note to what depth the floor of the boat sinks in the water.

2. Add pennies or washers to the ‘boat’, one at a time, and notice to what depth the floor of the ‘boat’ sinks in the water.

3. Imagine the ‘boat’ is a real boat, and the pennies or washers are passengers in the real boat. How many

passengers can your ‘boat’ hold before the boat sinks?

Question: A solid block of steel (or aluminium) will not float on water. Why can a huge ship, made out of steel or aluminum, or even concrete, float easily?

Have you ever noticed how it is easier to lift something when it is under water? This is because water exerts an upward buoyant force on objects placed under the water. In fact, any object that is partly or fully submerged in water will appear to weigh less by an amount exactly equal to the weight of the water that the object displaces!

An object like a boat will sink down in the water until it has displaced a volume of water with a weight equal to its

own weight, and then float at that level.

Archimedes was first to investigate the physics involved in buoyancy and floating objects. Archimedes was a brilliant Greek mathematician/philosopher, who lived from 287 B.C. to 212 B.C.

Archimedes’ Principle says that if an object is immersed in a fluid, it is buoyed up by a force equal to the weight of the fluid that the object displaces.