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 thing looks different, but it’s still the same material. You can often reverse it (like melting ice — you can freeze it again).
- A
chemical change means something new is made. It usually can’t be undone easily (like burning wood — you can’t turn ash back into wood).
---
1.
Fireworks → When fireworks explode, they make light, sound, and smoke. New substances are formed.
→
Chemical change
2.
Breaking a pencil → You’re just snapping it in two. It’s still wood and graphite. No new stuff is made.
→
Physical change
3.
Baking a cake → The batter turns into a fluffy cake. Heat causes reactions that change the ingredients forever. You can’t unbake a cake!
→
Chemical change
4.
Melting ice → Ice turns to water. But it’s still H₂O. If you cool it, it becomes ice again.
→
Physical change
5.
Popping popcorn → The kernel bursts open because of steam inside. It changes shape and texture, but it’s still corn.
→
Physical change *(Note: Some might argue heat causes chemical changes too, but at this level, popping is mostly physical — the starch expands, no new substance is created like in burning.)*
6.
Burning wood → Wood turns to ash, smoke, and gases. Totally new materials. Can’t un-burn it.
→
Chemical change
7.
Boiling water → Water turns to steam. Still water molecules. Cool it down, it becomes liquid again.
→
Physical change
8.
Frying an egg → The clear part turns white and solid. Heat changes the proteins permanently. You can’t unfry an egg.
→
Chemical change
9.
Breaking a window → Glass shatters, but it’s still glass. Just smaller pieces.
→
Physical change
---
Final Answer:
- fireworks → chemical change
- breaking a pencil → physical change
- baking a cake → chemical change
- melting ice → physical change
- popping popcorn → physical change
- burning wood → chemical change
- boiling water → physical change
- frying an egg → chemical change
- breaking a window → physical change
Parent Tip: Review the logic above to help your child master the concept of physical and chemical change worksheet.
