Modeling allows us to make our own sense of what and why something is happening. Conceptual models are shared and explicit representations or analogies of phenomena and are used by scientists to help them understand the world around us. Models are used in all areas of science and offer external versions of mental concepts. Models are not a perfect representation; they are a simplified version of a system that highlights certain areas while ignoring others.

Everything around us is made of atoms: the clothes we wear, the air we breathe, the water we drink, and ourselves. These atoms form roughly 92 naturally occurring elements on Earth, which then form everything we know. The result of these combinations can come in the form of elements, compounds, or mixtures, depending on their atomic makeup. While compounds and mixtures can be separated through a variety of techniques, elements cannot, as they exist in the purest form possible. Introducing students to atoms, elements, compounds, and mixtures will provide them with an important foundation that will help them grasp more complex concepts in chemistry.