Physical changes alter the form of a substance but do not create new substances, while chemical changes result in one or more new substances forming. Signs of a chemical change include a change in color, scent, the release or absorption of heat, or fizzing. Examples provided demonstrate whether various processes like burning wood, rusting iron, melting butter, and dissolving salt are physical or chemical changes, and whether they are reversible.

1. Physical and chemical
change

2. Physical change
A change that doesn’t result in
a new substance

3. Physical change

4. Physical change

5. Physical change

6. Chemical change
A change that results in one or
more new substances.

7. Signs of chemical change
1. Change in colour
2. Change in scent (odour)
3. Fizzing
4. Heat released or absorbed.

8. Chemical change

9. Chemical change

10. Chemical change

11. Is it physical or chemical change ?
Folded paper
Physical

12. Is it reversible or irreversible change ?
Blowing a balloon
physical
Is it physical or chemical change ?

13. Is it reversible or irreversible change ?
Burning wood
chemical
Is it physical or chemical change ?

14. Is it reversible or irreversible change ?
Iron rust
chemical
Is it physical or chemical change ?

15. Is it reversible or irreversible change ?
Melting butter
physical
Is it physical or chemical change ?

16. Is it reversible or irreversible change ?
Burning match stick
chemical
Is it physical or chemical change ?

17. Is it reversible or irreversible change ?
Toasting bread
chemical
Is it physical or chemical change ?

18. Is it reversible or irreversible change ?
Freezing orange juice
physical
Is it physical or chemical change ?

19. Is it reversible or irreversible change ?
Dissolving salt in water
physical
Is it physical or chemical change ?

20. Is it reversible or irreversible change ?
Melting wax
Burning thread chemical
physical
Is it physical or chemical change ?

21. Is it reversible or irreversible change ?
Ice turning into water
physical
Is it physical or chemical change ?

22. Is it reversible or irreversible change ?
Sharpening a pencil
physical
Is it physical or chemical change ?