Question

What does increased specific gravity mean?

Answer 1

Increased density via increased mass or decreased volume or both.

Explanation:

The specific gravity (also called relative density) of a substance is the ratio of the density of that substance to the density of water at `4^@C`, at which temperature water has its maximum density.

`therefore SG=rho_(rel)=rho_s/(rho_(H_2O at 4^@C)`.

So if the specific gravity increase, it means the density of the material has increase and since density is the mass per unit volume (`rho=m/V`), there are different ways this is possible - either the mass increases or the volume decreases, or both.
(Example in a black hole, as the mass increases and volume decreases, so the density increases and so the specific gravity also increases).