# Buoyancy

When water is drawn from a well with a bucket tied to a long rope. It is easy to lift the bucket when it is immersed in water. But as soon as it is out of water, it suddenly appears to be heavier. When a body is partly or completely immersed in a fluid, it experiences an upward force from the liquid displaced, which is called buoyant force.

Activity 1
Take a very heavy brick. Fill a tub with water and immerse the brick in it. Now slowly lift it out of water. As long as the brick remains underwater, it is easy to lift but the moment it is out of water, the same brick seems to be heavy.

A body appears to lose some weight when immersed in a liquid due to a property of liquids called buoyancy. The body loses weight when immersed in a liquid because the liquid exerts an upward force on the body. The upward force experienced by a body which is partly or completely immersed in a liquid is called the buoyant force. It is due to this force that the weight of a body immersed in a liquid appears to be less than its actual weight.

The weight of a body is the force with which it is pulled downwards by the gravity of the earth. A body immersed in a gas also experiences a buoyant force. Liquids and gases are called fluids.

When a body is partly or completely immersed in a fluid, it experiences an upward force called buoyant force.