Learning and Teaching about Matter in the Middle–School Years

The atomic–molecular theory is one of the most important contemporary scientific theories. Its basic tenets are few and simple, offering parsimonious and elegant explanations of why and how materials differ and change phase, and enter into chemical reactions. Yet most high-schoolers display major misconceptions about the nature, behavior, and structural arrangements of atoms, and about atomic–molecular accounts of macroscopic properties and phenomena. We argue that this is not inevitable and is no reason to delay teaching the atomic–molecular theory (AMT) until high school.