Does density vary with the of volume of a body?

Answer 1

The density of an object is its mass divided by its volume.

The density of an object varies inversely with its volume.

Thus, if you can compress and object, like a sponge, you can increase its density.

Normally, we say the density of a type of material is an intrinsic property, i.e. if you have a big piece of it or a small piece of it, they both have the same density because the large piece has a proportionately larger volume than the small piece.

So, a gallon of water has the same density as a milliliter of water.

Note the distinctions here.

1. An object, like a car, can be made of many different materials and the object, as a whole, has some density which is the mass of the car divided by the volume of the car. If you crush the car, you increase its density.
2. Each type of material also has a density. The glass in the window of the car has its own density, a property inherent in that type of glass. The steel in the car has the density of steel, a property inherent in that type of steel.
If you have a type of material and you compress it, you increase its density.

If you don't compress it, then two different pieces of the same uniform material, large or small, will have the same density under the same conditions of pressure and temperature. That is what we mean by density is an intrinsic property of a material.