1. What are chemical and physical changes?
Aim:
What are chemical and physical changes?

2. Differentiate the meaning of chemical change and physical change
Objectives
Differentiate the meaning of chemical change and physical change

3. Vocabulary
Chemical change
Physical change

4. Crumble a piece of paper What are the differences?
Investigate:
Crumble a piece of paper
Rip a piece of paper
Burn a piece of paper
What are the differences?

5. List some examples of Physical Change
cutting, freezing, boiling
does NOT produce a new substance
Commonly associated with the phase change diagram
Solid liquid gas

6. What Exemplifies a Chemical Change?
Materials combine to form a new substance
Burning paper
Rusting Iron

7. Digestion has both Physical and Chemical Changes
Chewing of food by teeth into smaller pieces
Stomach/Small Intestine breaks down food into individual molecules (fats, sugars, amino acids)

8. Definition
Chemical change: The substances present at the beginning of the change are not present at the end; new substances are formed. The change cannot be “undone.”

9. Examples Physical Changes Aluminum foil is cut in
Clay is molded into a new shape.
Butter melts
Water evaporates from the surface of the ocean.
a juice box in the freezer freezes.
.Rubbing alcohol evaporates on your hand
Chemical Changes
Milk goes sour.
Jewelry tarnishes.
Bread becomes toast.
Rust forms on a nail left outside.
Gasoline is ignited.
Hydrogen peroxide bubbles in a cut.

11. Gas or precipitate (solid) produced
Name at least 5 clues that would indicate there has been a chemical change in matter.
color
energy change
odor
Gas or precipitate (solid) produced
not easily reversed

12. Odor Change

13. Color Change

14. Energy Change

15. Precipitate

16. Not easily reversed

17. PHYSICAL CHANGES MELTING FREEZING solid to liquid
As the ice gains energy – more molecules vibrate
eventually the bonds that form the ice crystals break and the ice melts.
FREEZING
the reverse: looses thermal energy
The molecule move about more slowly
Eventually the ice crystal start to form

18. Reverse of Vaporization is called CONDENSATION
EVAPORATION
Water slowly gains energy
Gradually converts to gas
“sweating”
BOILING
Water rapidly gains energy
Quickly converts to gas
Reverse of Vaporization is called CONDENSATION

19. SOLID > GAS
SUBLIMATION
Dry Ice

20. Practice Quiz

21. Summary
REVIEW VOCABULARY –

22. Class Activity:
Worksheets Concepts 12-4

23. AIM: What are habitats and niches?
Homework:
INTERNET QUESTIONS
Paragraph