Density is a measure of how much mass is in a certain volume of a substance. It is used to compare how heavy different materials are for their size. Dense materials have more mass in the same amount of space. Density can vary between different substances.

Density is found in all materials on Earth and in space. It is measured in units such as grams per cubic centimeter. Scientists use density to identify and compare substances.

Different materials have different densities, such as metals, liquids, and gases. Density is part of how substances are described in science. It is used in many fields, including physics and chemistry.