States of matter

This module helps students develop the concepts of “substances” and “chemical reactions.” Students see that chemical reactions enable us to make new materials by transforming the ones we have. Students model the molecular structure of solids liquids and gases. Students use baking soda, calcium chloride and other common substances to discover that when certain substances combine, a chemical reaction takes place, and new substances are formed. Students measure the mass of substances before and after melting, dissolving, and a chemical change to investigate the question: Is mass conserved during physical and chemical changes?