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Density of substance and Relative density

Topics

Density
Relative Density

Density:

Density is a measure of how much mass is packed into a given volume. It is calculated using the formula:

Density = `"Mass" / "Volume"`

The SI unit of density is kilograms per cubic meter (kg/m³). Density helps us determine how heavy or light a substance is for its size.
It is a very useful property, especially when we need to check the purity of a material.

For example, if a metal has a different density from what is expected, it might contain impurities.

Relative Density:

Relative density compares the density of a substance to the density of water.

Relative Density = `"Density of substance" / "Density of water"`

Because it is a ratio of two densities (both measured in kg/m³ or any other unit), relative density has no unit. It’s just a number.

Specific Gravity:

Another name for relative density is specific gravity. It indicates the relative weight of a substance in relation to water. A material that is heavier than water and has a relative density greater than 1 is likely to sink. It will float if it is less than 1, as it is lighter than water.

For example, if the relative density of gold is 19.3, it means gold is 19.3 times heavier than water.

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