The units of density depend on the units used for mass and volume. The most commonly used units are grams per cubic centimetre (g/cm³) or kilograms per cubic metre (kg/m³). These balloons are the same ...

It is tempting to think that some materials are always heavier than other materials. For example, someone might say that metal is heavier than air. But it depends on how much of each material there is ...

Copper atoms are larger than aluminum atoms. There are fewer copper atoms than aluminum atoms in the cubes. Copper atoms are much more massive than aluminum atoms. The extra mass makes copper more ...