Worksheet for identifying physical and chemical changes in everyday occurrences.

To solve this worksheet, we need to distinguish between physical and chemical changes.

Understanding the Difference:
* Physical Change (P): The appearance or form of the matter changes, but the kind of matter in the substance stays the same. Think of it like cutting, breaking, melting, or mixing without a reaction. It’s usually reversible or just looks different.
* Chemical Change (C): A new substance is created. The matter changes into something completely different. Signs include burning, rusting, cooking, digesting, or bubbling/fizzing due to a reaction.

Step-by-Step Analysis:

1. Crushing a rock: You are just breaking it into smaller pieces. It's still rock. -> Physical (P)
2. Digesting food: Your body uses acids and enzymes to break food down into nutrients. The food turns into energy and waste, which are new substances. -> Chemical (C)
3. Water evaporating: Liquid water turns into water vapor (gas). It is still H2O, just in a different state. -> Physical (P)
4. Fireworks exploding: This involves burning and creating light, heat, and sound. New gases and ash are created. -> Chemical (C)
5. Getting a haircut: You are cutting hair. The hair is still hair, just shorter. -> Physical (P)
6. An ice cube melting: Solid ice turns into liquid water. It is still water. -> Physical (P)
7. A candle burning: The wax burns to create smoke, heat, and light. The wax turns into carbon dioxide and water vapor. -> Chemical (C)
8. Salt dissolving in water: The salt disappears into the water, but if you let the water evaporate, the salt is left behind. No new substance is made. -> Physical (P)
9. Silver tarnishing: The silver reacts with air to form a dark layer (tarnish) on top. This is a new substance. -> Chemical (C)
10. Glass breaking: The glass shatters, but it is still glass. -> Physical (P)
11. Hair bleaching: Bleach changes the chemical structure of the pigment in your hair to remove color. -> Chemical (C)
12. A bicycle rusting: Iron reacts with oxygen and moisture to form rust (iron oxide), which is a new reddish-brown substance. -> Chemical (C)
13. Frying an egg: The heat cooks the egg, changing its texture and color. You cannot "un-fry" an egg. -> Chemical (C)
14. Baking soda reacting with vinegar: They fizz and bubble, creating a gas (carbon dioxide). This is a classic chemical reaction. -> Chemical (C)
15. Oil mixing with water: The oil just floats on top. They don't react; they just sit together. -> Physical (P)
16. Cutting grass: You are shortening the grass blades. The grass is still grass. -> Physical (P)
17. Butter melting: Solid butter turns into liquid butter. -> Physical (P)
18. Ethanol evaporating: Liquid alcohol turns into gas. Like water evaporating. -> Physical (P)
19. Grass growing: Plants grow by using photosynthesis to create sugars and new cells. This is a biological chemical process. -> Chemical (C)
20. A tire is inflating: You are adding air to the tire. The rubber and the air don't change their chemical identity; the tire just gets bigger. -> Physical (P)

Final Answer:
1. P
2. C
3. P
4. C
5. P
6. P
7. C
8. P
9. C
10. P
11. C
12. C
13. C
14. C
15. P
16. P
17. P
18. P
19. C
20. P