McDonalds© informed us that its Big Mac® is made of: two all beef patties, special sauce, lettuce, cheese, pickles, onion on a sesame seed bun! What does this have to do with matter? Well, a Big Mac®, like most matter in the world, is made up of smaller parts which makes the whole. All matter is made up of atoms that are far too small to see.

In this unit, you will learn that atoms are in perpetual motion and the more energy atoms contain the faster they move. You will also explore how atoms combine to form molecules. All matter is made up of atoms and molecules that have measurable mass, volume, and density. Density is a measure of the compactness of matter. Have fun as you explore the structure of matter in the following pages.