Volume is the quantity of three-dimensional space occupied by a liquid, solid, or gas. Common units used to express volume include liters, cubic meters, gallons, milliliters, teaspoons, and ounces, though many other units exist.

### Key Takeaways: Volume Definition

- Volume is the three-dimensional space occupied by a substance or enclosed by a surface.
- The International System of Units (SI) standard unit of volume is the cubic meter (m
^{3}). - The metric system uses the liter (L) as a volume unit. One liter is the same volume as a 10-centimeter cube.

## Volume Examples

- As a volume example, a student might use a graduated cylinder to measure volume of a chemical solution in milliliters.
- You could buy a quart of milk.
- Gases are commonly sold in units of volume, such as cubic centimeters, cm
^{3}, or cubic liters.

## Measuring Volume of Liquids, Solids, and Gases

Because gases fill their containers, their volume is the same as the internal volume of the container. Liquids are commonly measured using containers, where the volume is marked or else is the internal shape of the container. Examples of instruments used to measure liquid volume include measuring cups, graduated cylinders, flasks, and beakers. There are formulas for calculating the volume of regular solid shapes. Another method of determining the volume of a solid is to measure how much liquid it displaces.

## Volume vs. Mass

Volume is the amount of space occupied by a substance, while mass is the amount of matter it contains. The amount of mass per unit of volume is a sample's density.

## Capacity in Relation to Volume

Capacity is the measure of the content of a vessel that holds liquids, grains, or other materials that take the shape of the container. Capacity is not necessarily the same as volume. It is always the interior volume of the vessel. Units of capacity include the liter, pint, and gallon, while the unit of volume (SI) is derived from a unit of length.