Looking for a fun, hands-on way to teach physical and chemical changes while strengthening your students’ writing in science? This Slime Lab is a student favorite that combines an engaging activity with the Claim, Evidence, Reasoning (CER) framework. Students love making slime - and you’ll love how the lesson guides them to collect data, analyze their results, and write a strong scientific explanation.

What the Lesson is About: In this lab, students create slime and investigate whether the process represents a physical or chemical change. Through careful observations and guided data collection, they will learn how scientists use evidence to support their claims. An optional extension takes the lesson further by having students test the Law of Conservation of Mass.

This lesson is designed for grades 6–8 and works perfectly as part of a unit on matter and chemical reactions, as practice with CER writing, or as a stand-alone activity to hook students into chemistry concepts.