Answer:
The mass per unit volume of a substance is called density of that substance.
Step-by-step explanation:
So, How does it works ?
For example: Density of gold is 19300kg/cubic meter. It means that if there gold having volume of a cubic meter its mass will be 19300 kg... Density of plastics are less than that of density of metals... I.e. if we take plastic having volume 2 cubic meter & gold having volume 1 cubic meter we will find mass of gold is far more compared to that of plastic.. Thus, density refers how much tightly the molecules of a substance are bonded together.