1. Physical and Chemical Changes Unit 4—

2. Concept of Change Change: the act of altering a substance

3. Physical Change Physical change: a change that occurs that does not change the identity of the substance  Melting ice( change in state or phase) Beverly?  Freezing Kool-aid  Tearing paper  Boiling water (same as melting ice)Beverly?

4. Chemical Changes Chemical change: a change that occurs causing the identity of the substance to change  Burning  Digesting food  Reacting with other substances (give an example per reviewer) A chemical change is called a chemical reaction

5. Chemical Changes Cont’d Indicators of a chemical change: Production of light Change of heat (hotter or colder) Production of a gas (bubbles in a liquid) Color change Formation of a precipitate

6. Is it Physical or Chemical? ChangePhysicalChemical Melting cheese Burning wood Milk souring Wadding up paper Bicycle rusting