WHY DO THINGS FLOAT?

Is it because the ping pong ball is lighter than the water and the rock is heavier?

Untitled Slide

OBJECTS FLOAT OR SINK BECAUSE OF BUOYANCY

• Buoyancy is an upward thrust of force that balances the force of gravity
• Buoyancy is caused by increased pressure at greater depths in a liquid

An objects mass and density determines if it floats or not
The ping pong ball floats because the water is much more dense than the air inside the ball
The rock sinks because it has more mass in a smaller area than the water does

DID YOU KNOW?

• Fish use something called a fish bladder to let them rise or sink in water
• A fish bladder fills with oxygen to decrease a fishes density
• When the density of the fish goes down buoyancy pushes the fish up