Physical or Chemical Change?

1. Physical or Chemical Change? Vocabulary Chemistry

2. 1. Physical change… because the bits of dust are STILL made of WOOD. 2. Chopping wood (Chopping = cutting into large pieces) 2. 1. Physical change… because after the wood is chopped, it is STILL made of WOOD. Wood becoming sawdust (Sawdust is the small particles of wood that fall to the ground when you cut wood.)

3. 1. Physical change… because the sugar still exists; it is just broken up into bits in the drink. 2. Burned logs 2. Sugar dissolved in water (Dissolved = melted. When sugar dissolves in water, you cannot see the sugar anymore, but it’s there.) Chemical change… because the wood turns into smoke & ash. It cannot be changed back into WOOD. 1.

4. 1. 2. Salt and pepper mixed together Physical change… because the substances have NOT changed into new substances. 2. 1. Putting salad dressing on salad Physical change… because the salt and pepper still exist; they are just mixed with each other.

5. 1. Chemical change… because the metal is CHANGED into a NEW substance called RUST. 2. Fruit salad tossed together (“Tossed together” = mixed together) 2. Rusting bike (Rust occurs when metal reacts with oxygen. The oxygen is destroying the metal and breaking it down into very small pieces.) 1. Physical change… because the fruit has not changed into different substances.

6. 1. Gasoline burning (Inside an engine, gasoline burns (combusts) to produce energy so the car can go.) 2. Physical change… because the substance is STILL water, even though it’s frozen solid. Liquid water freezing (Liquids freeze when they get cold and turn into a solid.) 2. 1. Chemical change… because when something BURNS, it turns into NEW substances like smoke and smog.

7. 1. 2. Physical change… because it is STILL made of the same substance (water). Rocket fuel igniting (Ignite = to start a fire. When rocket fuel burns, it produces energy to make the rocket go.) Ice melting (Something melts when it changes from a frozen solid to a liquid.) 2. 1. Chemical change… because when something burns, it turns into NEW substances like smoke.

8. 1. Minerals forming (Minerals form deep within the earth when certain elements are changed due to the intense heat and pressure inside the earth.) 2. Physical change… Because it’s STILL all water…nothing new is made. 2. 1. Glaciers melting Chemical change… because NEW substances are made.

9. 1. Dead plants decomposing (Decomposing = the nutrients from something that was once alive, but now is dead, are going back into the ground and can be used again by other plants.) 2. Chemical change 2. Silver tarnishing (Tarnish forms on silver when the silver reacts with the oxygen in the air. It forms a greenish-black substance on the silver that can be removed with special polish.) 1. Chemical change

10. 1. 2. Firecrackers exploding Physical change 2. Ocean water evaporating and leaving salt behind (Evaporation occurs when water molecules float up into the air to form clouds. Anything that was in the water will stay behind.) 1. Chemical change

11. 1. Saliva dissolving starch in food (Saliva = the water your mouth produces. To dissolve = to break down into very small pieces using water. Starch = carbohydrates, a type of energy in food.) 2. Chemical change Saliva breaking the chemical bonds of meat protein (The liquid in your mouth reacts with the meat to separate the protein so your body can absorb it.) 2. 1. Chemical change

12. 1. 2. A tree’s leaves changing color in the fall (The leaves turn color because they are dying.) Physical change 2. 1. Glass breaking Chemical change

13. 1. 2. Baking Bread Physical change 2. 1. Paint Drying Chemical change

14. 1. 2. Making Kool-Aid Chemical change 2. 1. Milk souring Physical change Good → Bad

15. 1. 2. A rotting log Physical change Making an ice sculpture 2. 1. Chemical change

16. 1. 2. Burning a candle Chemical change A Penny turns green (Pennies are made of the element copper. Copper reacts to oxygen in the air by forming a green or brown coating.) 2. 1. Chemical change

17. 1. 2. An Alka-Seltzer in water (When the chemicals in the medicine combine with the water, carbon dioxide gas is released and the medicine dissolves into the water.) Physical change 2. Tearing a piece of paper in two 1. Chemical change

18. 1. 2. Reacting substances Physical change 2. Mixing blue and red paint to make purple 1. Chemical change + =

19. 1. 2. Physical change A magnet sticking to a refrigerator Conducting heat or electricity (The eye on the stove conducts (carries) heat to the pan, and the pan conducts heat to the food. The molecules in air conduct (allow to travel) lightening.) 2. 1. Physical change

20. Cooking pancakes 1. 2. THE END 2. 1. That’s all. Chemical change