# What is volume and what units are used to describe mass?

megamind-616 | Middle School Teacher | (Level 1) Associate Educator

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Volume is the amount of space an object occupies. The SI base unit for volume is the liter. Mass is the amount of matter in an object. The SI base unit for mass is the kilogram.

Volume can be measured one of two ways. To determine the volume of an object with straight edges (such as a square or rectangle), one would use the following equation:

length x width x height = volume of the object

However, if the object is irregularly shaped, then water displacement is used. Water displacement involves measuring the difference in water heights. An initial amount of water is placed in a graduated cylinder and the initial volume is recorded. Then, the object is gently placed in the water of the graduated cylinder. The water will rise (displace). This new volume of water is recorded. The volume of the object is the new volume minus the old.

Mass is determined using a balance.