All big things are built from smaller things. If we were to literally split hairs again and again, eventually we'd end up with single molecules made up of carbon and a bunch of other elements. If we were to cut up the molecules, we'd get to the really small stuff. Scientists call the smallest stuff an atom. Going backwards, atoms combine with other atoms to form molecules, and molecules combine with other molecules to form states of matter, which is where our story begins.
Matter behaves differently depending on whether it is part of the solid, liquid, or gas phase. The building blocks of matter are called particles and they can be atoms, molecules, or ions. These particles may be ordered or clumped, close together or far apart, moving faster than a cheetah or slower than a turtle. Matter has a way of keeping us on our toes by shape shifting and transforming right before our eyes. In this section, we'll examine the different states of matter and what happens when matter goes from one state to another.