Volume is the amount of space that an object occupies. Volumes of liquids must often be measured in chemical laboratories. One liter is equal to 1000 cubic centimeters. One thousand cubic centimeters is the volume of a cube that has edges ten centimeters, or one decimeter long—hence the definition of the liter as one cubic decimeter. Liters and milliliters are not SI units. The SI unit for volume, m3, is derived from the base unit for length, the meter. However, a cubic meter is too large to be a convenient unit for laboratory use, and chemists usually measure volumes of liquids in liters and milliliters.