Let’s go through each example one by one and decide if it’s a
physical change or a
chemical change.
Remember:
- A
physical change means the substance looks different, but it’s still the same stuff — no new thing is made. Like breaking, melting, boiling (if it’s just turning to gas), or crushing.
- A
chemical change means something new is made — like burning, cooking, rusting, or exploding. You can’t easily turn it back.
---
1.
Fireworks → When fireworks explode, they make light, sound, and smoke. New chemicals are formed.
→
Chemical change
2.
Breaking a pencil → You’re just snapping wood and graphite. It’s still pencil pieces.
→
Physical change
3.
Baking a cake → The batter turns into cake — you can’t unbake it! Heat causes reactions that make new substances.
→
Chemical change
4.
Melting ice → Ice becomes water. Still H₂O — just changed shape/state.
→
Physical change
5.
Popping popcorn → The kernel bursts open because of steam inside. The corn is still corn — just puffed up.
→
Physical change *(Note: Some might argue heat causes slight chemical changes, but for school level, this is usually considered physical since it’s mostly expansion due to water vapor.)*
6.
Burning wood → Wood turns to ash, smoke, and gases. Can’t un-burn it.
→
Chemical change
7.
Boiling water → Water turns to steam. Still water molecules — just gas now.
→
Physical change
8.
Frying an egg → The clear part turns white and solid. That’s proteins changing forever — can’t un-fry it.
→
Chemical change
9.
Breaking a window → Glass shatters, but it’s still glass. Just in smaller pieces.
→
Physical change
---
Final Answer:
- Fireworks → Chemical
- Breaking a pencil → Physical
- Baking a cake → Chemical
- Melting ice → Physical
- Popping popcorn → Physical
- Burning wood → Chemical
- Boiling water → Physical
- Frying an egg → Chemical
- Breaking a window → Physical
Parent Tip: Review the logic above to help your child master the concept of worksheet on physical and chemical changes.
