2. Physical and Chemical Change When a candle burns we see both physical and chemical change. PHYSICAL CHANGE WAX MELTING CHEMICAL CHANGE WAX BURNS

3. What is a Physical Change? Physical changes change the appearance of a substance and involve changes in size, shape or phase of matter. Examples: MELTING ICE MELTING EVAPORATION LAKE STEAMING CONDENSATION GLASS SWEATING FREEZING ICE FREEZING CHANGE SIZE GLASS BREAKING CHANGE SHAPE MOLDING CLAY PHASE CHANGES

4. What is a Physical Change? They also occur during the mixing and dissolving of substances. Examples: MIXTURE IRON AND SAND MIXTURE DISSOLVING SUGAR OR SALT Physical changes DO NOT change the chemical composition or identity of a substance. No new substance is formed.

5. What is a Chemical Change? In a chemical change: One or more new substances are formed. Change is difficult or impossible to reverse. There is usually an energy change. OBSERVATIONS Color Change Gas/Bubbles Precipitate Requires Heat To Happen Gives Off Heat Produces Light Original Material Or Materials Disappear EXAMPLES Zinc and HCL Glycerol and Potassium permanganate Lamp Burning Fuel

6. Common Examples of Chemical Change Oxidation Rusting Tarnish Burning Wood OBSERVATIONS Color Change Original Material Disappears Gives Off Heat Produces Light Original Material Disappears EXAMPLES

7. Physical AND Chemical Changes Like the burning candle, physical and chemical changes can be observed in a single process or situation depending on what you are looking at. Example: PHYSICAL CHANGE Biting A Piece Of Apple CHEMICAL CHANGE Enzymes and HCL In Mouth and Stomach Breaking Down Food DIGESTION

8. Physical AND Chemical Changes PHYSICAL CHANGE Wearing Away of Rock By Water Over Time CHEMICAL CHANGE Carbonic Acid Eating Through Limestone to Make Caverns ROCK CYCLE Like the burning candle, physical and chemical changes can be observed in a single process or situation depending on what you are looking at. Example:

9. Application: Physical or Chemical Change Evaluate each picture as being a Physical or Chemical Change. How about now? Cutting an Egg Bending a Nail Water CondensingGlass Falling and Breaking

10. Evaluate each passage as being a Physical or Chemical Change. Application: Physical or Chemical Change Dissolving sugar in water Putting butter on hot toast Clothes drying on a clothes-line Milk going sour Iron rusting Ripping paper Stomach acid breaking down an apple Physical Change Chemical Change

11. Test your mastery and evaluate each as a Physical or Chemical Change. Application: Physical or Chemical Change Mixing Cake Mix Baking Cake Mix VERSUS Mixing Alka Seltzer in Water Mixing Salt in Water VERSUS