This activity begins with an analysis of the chemical equation for the reaction between vinegar and baking soda. Students try this reaction on their own, experimenting with how changing the amount of one or more of the reactants affects the amount of products. Students analyze a molecular model to follow the number and type of atoms from reactants to products. Through experimentation and discussion, students are asked to make connections between the written chemical equation, the molecular model, and the real substances in the reaction. This lesson includes digital images, a student reading, and a detailed teacher’s guide.