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Density as mass over volume

The density ($$\rho$$) of an object is its mass $$\Tred{(m)}$$ divided by its volume $$\Tblue{(V)}$$.$$$\rho = \frac{\Tred{m}}{\Tblue{V}}$$$

The symbol $$\rho$$ comes from the Greek alphabet and is called 'rho'. It should not be confused with $$p$$ from the Latin alphabet.

A $$1 \ucm^{3}$$ piece of lead is heavier than a $$1 \ucm^{3}$$ piece of plastic because lead is denser than plastic.

The SI unit of density is $$\text{kg/m}^{3}$$.

A person has a mass of $$55 \text{ kg}$$ and a volume of $$0.05 \text{ m}^{3}$$. Their density is $$$\rho = \frac{\Tred{55 \text{ kg}}} {\Tblue{0.05 \text{m}^{3}}} = 1100 \text{kg/m}^{3}$$$

The table below shows the density of some well-known materials at room temperature.
Material Helium Air Water (liquid) Gold
Density ($$\text{kg/m}^{3}$$) $$0.18$$ $$1.29$$ $$1,000$$ $$19,300$$
Gold has a very high density.
Gold has a very high density.