What units are used to measure density?

Density is typically measured in kilograms per cubic metre (kg/m³) or grams per cubic centimetre (g/cm³).

Density is a measure of how much mass is contained in a given volume. It is a fundamental concept in physics and is particularly important in fluid dynamics. The standard unit of density in the International System of Units (SI) is the kilogram per cubic metre (kg/m³). This means that if you have a cube that is one metre on each side, and the total mass of everything inside that cube is one kilogram, then the density of the substance inside the cube is one kilogram per cubic metre.

However, for smaller quantities, it is often more convenient to use grams per cubic centimetre (g/cm³). This is particularly common in chemistry and materials science. One gram per cubic centimetre is equivalent to 1000 kilograms per cubic metre.

In addition to these, there are other units of density depending on the context. For example, in the petroleum industry, density is often measured in pounds per gallon or kilograms per litre. In the field of aerodynamics, air density is typically given in kilograms per cubic metre.

It's important to remember that density is a property of the material itself, not of any particular quantity of that material. This means that a small piece of gold has the same density as a large piece of gold. The density of a substance can change with temperature and pressure, but for most substances, these changes are small.

Understanding density and how to calculate it is a fundamental part of studying physics. It's a concept that you'll encounter in many different areas, from understanding how ships float to predicting the behaviour of gases.