# Buoyancy.

## Presentation on theme: "Buoyancy."— Presentation transcript:

Buoyancy

Just Think! What did it have to with Bouyancy?
Why did the Titanic Sink? What did it have to with Bouyancy?

Objectives Students will be able to define buoyancy.
Students will be able to explain why some objects sink while others float. Students will be able to explain what happened to the Titanic when it hit the iceberg.

Buoyancy In simple terms, buoyancy is the ability of an object to float. Whether or not a given object will float is determined by the buoyant force on the object. This force is caused by the difference between the pressure at the top of the object, which pushes it downward and the pressure at the bottom of the object which pushes it upward. Because the pressure at the bottom of the object is always greater than the pressure at the top, every submerged object feels an upward buoyant force. The magnitude of this buoyant force is equal to the weight of the fluid that is displaced by the submerged object. The weight of the water that is displaced by this block of wood is equal to the buoyant force acting on the block. (excerpt from

Buoyancy Why do some objects float, while other objects sink?
A coin sinks because it weighs more than the water it displaces. The aluminum ball floats because it contains air within its folds. Air weighs less than water, so the ball weighs less than the water it displaces.

Buoyancy Archimedes was an ancient Greek scientist who discovered that floating objects are supported by an upward force called buoyancy. ( P.S.- he discovered this while taking a bath, and decided to run through the streets shouting out “Eureka, Eureka!”) Buoyant force is equal to the weight of the liquid that the force displaces. The theory concerning buoyancy is called Archimedes Principle.

Why did the Titanic Sink?
After it hit the iceberg, water began to fill the air filled compartments on the ship. The added weight of the water, combined with the weight of the ship became greater than the buoyant force supporting the ship. We all know what happened after that!

Let’s go to the Video!