What is buoyancy?

Arccoding to Archimedes principle ,when a body is wholly or partially immersed in a fluid ,it experience an upward thrust equal to the weight of the fluid displaced . This upward thrust is also known as Buoyancy.

Every object experiences the upward thrust as it dipped in a liquid . The buoyancy force is the reason behind floating of objects .If the weight of volume displaced by object is more than the weight of the object ,then the object will float on the surface. And If the weight of volume displaced by object is less than the weight of the object.Then the object will sink in the liquid.

If you look at the figure its clear in the figure that densities of object and liquid are different , so there exist a buoyancy force which is acts upward opposite in the direction of gravity.