Question

Define the term density of a substance.

Answer 1

Hint:Density of a substance or an object refers to how much stuff the object has in a unit volume. The Greek scientist, Archimedes came up with the principle of density. Density is considered to be a relationship between the mass of a substance and the volume taken up by it.

Complete step by step answer.

Step 1: Mention the general definition of density and give its formula for calculations.
The density of a material is defined as its mass per unit volume. It is a measure of how closely packed the matter in a material is. For a particular material, its value of density will be unique i.e. different materials have different densities. Density is represented by $\rho $. For calculations, the standard formula for the density of a body is given by, $\rho = \dfrac{m}{V}$ where $m$ is the mass of the body and $V$ is the volume it occupies.
Generally, liquids and gases are less dense than solids. This is because, in liquids, the particles can slide around one another and in gases, the particles are free to move in all directions whereas, in solids, the particles are tightly packed and motion of particles is limited.

Additional information:The knowledge of density finds many applications. It helps one to separate quantities like oil and water that have different densities. Archimedes found out that an object floats on water or any other liquid based on the difference in densities of the object and that of water or the liquid.

Note:Qualitatively, the density of an object shows how heavy an object is at constant volume. When we say that different materials have different densities we, in fact, mean that for the same volume, the different materials weigh differently. From the above formula for density, we can obtain its S.I unit to be kilogram per cubic metre as the S.I unit of mass is kilogram and that of volume is cubic metre.