This lesson is an introduction to pure substances and mixtures, and is part of a five-lesson series on Structure and Properties of Matter (click for bundle). This lesson supports MS-PS1 (Structure and Properties of Matter) of the NGSS. The handout and included answer key work together with videos and links found at Pure Substances vs. Mixtures on the How About Science? website. Here are some things you will like about “How About Science?” activities!∙ NO PREP (other than making copies