**Archimedes' Principle and Density**

Objects under water feel lighter than in air.

The water exerts an upward force called the buoyant
force.

The buoyant force acts
in the upward direction, against the force of gravity, so it makes an object feel lighter.

Any object submerged in a fluid displaces, or takes the place of, a volume
of fluid equal to its own volume.

For an object floating on the surface, the volume of fluid displaced is equal to the volume
of the part of the floating object that is submerged.

Archimedes principle states that the buoyant force on an object is equal to the weight of the fluid
displaced by the object.

If the
weight of an object in a fluid is greater than the buoyant force, the net force will be downward and the object will sink.

If the weight of an object is less than the buoyant
force, the object will float.

If
the weight of an object is exactly equal to the buoyant force, the object will remain at some level within the fluid