Density of Wood
Density of the wood is less than density of water, so it keeps on floating on the surface of the water.
Density of Metal
Density of a metal is more than density of water, so it sinks into water when we keep it at the top surface of water.
Upthrust
When an object partially or completely immersed in a liquid, bottom of the object experiences greater pressure than the top. The pressure difference between top and bottom exerts an upward force, known as upthrust.
