Mass

Mass is a description of how difficult it is to change an object's motion &emdash; that is, how difficult it is to accelerate an object.

Mass is measured in kilograms (kg).

In this class--as in all of Science and almost all the rest of the world--we will measure mass in units of kilograms (kg).

There is an important difference between mass and weight. An object with a mass of one kilogram (1 kg) has a weight of 2.2 lbs (or 9.8 newtons--but we will learn about newtons shortly).