1. Physical and Chemical Changes
How to tell the difference

2. Physical Change-
physical properties change, but the substance is the same
Change in what you see but does not produce a new substance
Painting a house, cutting hair, ironing shirt, melting water/boiling water

3. Some physical changes are reversible, some are not
Reversible—freezing & melting water, braiding hair
Non-reversible—slicing a tomato, peeling an orange

4. Indicators of a Physical Change

5. It’s a physical change if
It changes shape or size
It dissolves.

6. It changes phase (freezes, boils, evaporates, condenses)
It’s a physical change if...
It changes phase (freezes, boils, evaporates, condenses)

7. Chemical Change Chemical Change-
when substances react to form one or more NEW substances
Look for permanent change in color, gas bubbles, leftover solid
Non-Reversible

8. Indicators of a Chemical Change

9. It’s a chemical change if….
It burns
Temperature changes without heating/cooling

10. It’s a chemical change if...
It bubbles (makes a gas)

11. It’s a chemical change if...
It changes color permanently
It forms a leftover solid

12. Examples: Silver ring that turns green Rusting cars
Copper pennies turning green
Baking powder in cake – cake rises
Vinegar and baking soda
Adding vinegar to milk
Lighting a match
Explosion or burning of wood

13. What kind of change is it if someone...
Tears up paper?
Physical change
Mixes salt and water?

14. What kind of change is it if someone...
Burns paper?
Chemical change
Evaporates salt water?
Physical change