Archimedes and the Golden Crown

Source: Archimedes and the gold crown, Constructivism

The concept of density can be traced back to ancient Greece and a mathematician named Archimedes.

Watch the following video to learn more about Archimedes and the golden crown.

Density is a physical property of matter and is a size independent property. In other words, density can be observed using the sense and the amount of the substance present does not change the density. Density is a comparison of the amount of matter to the amount of space. In other words, it is a measure of how closely "packed," or "crowded," the materials are in a defined area. Look at the two pictures below. Each box is the same size. The balls in the box are the same size and have the same mass. Which box is more crowded?

Box B is more crowded; therefore, we can say it has more mass per unit of volume. Density is defined as mass per unit of volume, so box B has a greater density. Each element and compound has a unique density associated with it. The density of a material can be used to distinguish it from other materials.

We calculate density using the formula

In math class, you have learned that a rate can be defined as a ratio that compares, by division, two quantities having different attributes. Density compares mass and volume by division. Therefore, density can be defined as a rate.