Examples of physical and chemical changes in everyday life.
A grid of 20 images illustrating various physical and chemical changes, including cutting an apple, baking a cookie, lighting a match, melting ice, roasting a marshmallow, freezing water, burning a candle, dissolving sugar, ripping paper, slicing bread, boiling water, crushing a can, breaking a mirror, a decaying leaf, frying an egg, mixing vinegar and baking soda, a rusting bike, burning wood, cutting grass, and digesting food.
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Step-by-step solution for: Physical and Chemical Changes interactive worksheet for 7 | Live ...
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Show Answer Key & Explanations
Step-by-step solution for: Physical and Chemical Changes interactive worksheet for 7 | Live ...
The task in the image appears to be about identifying whether each activity represents a physical change or a chemical change. Here's a breakdown of the solution:
- Physical Change: A change in which the physical properties of a substance (e.g., shape, size, state) are altered, but the chemical composition remains the same.
- Chemical Change: A change in which the chemical composition of a substance is altered, resulting in the formation of new substances.
Let's analyze each activity and categorize it as either a physical change or a chemical change.
---
#### Row 1
1. Cutting an apple
- Physical Change: The apple is being cut into pieces, but its chemical composition remains unchanged.
2. Baking a cookie
- Chemical Change: Baking involves heating, which causes chemical reactions (e.g., caramelization, Maillard reaction), changing the ingredients into a new substance (cookie).
3. Lighting a match
- Chemical Change: Lighting a match produces heat, light, and smoke, indicating a chemical reaction where new substances are formed.
4. Melting ice
- Physical Change: Melting is a phase change from solid to liquid, but the chemical composition of water (H₂O) remains the same.
5. Roasting a marshmallow
- Chemical Change: Roasting causes the sugar in the marshmallow to caramelize, forming new compounds through chemical reactions.
---
#### Row 2
6. Freezing water
- Physical Change: Freezing is a phase change from liquid to solid, but the chemical composition of water (H₂O) remains unchanged.
7. Burning a candle
- Chemical Change: Burning involves combustion, where wax reacts with oxygen to produce carbon dioxide, water, and heat, forming new substances.
8. Dissolving sugar
- Physical Change: Dissolving sugar in water separates the sugar molecules but does not change their chemical composition.
9. Ripping paper
- Physical Change: Ripping paper tears it apart physically without altering its chemical structure.
10. Slicing bread
- Physical Change: Slicing bread changes its shape but does not alter its chemical composition.
---
#### Row 3
11. Boiling water
- Physical Change: Boiling is a phase change from liquid to gas, but the chemical composition of water (H₂O) remains the same.
12. Crushing a can
- Physical Change: Crushing deforms the can physically but does not change its chemical composition.
13. Breaking a mirror
- Physical Change: Breaking a mirror shatters it into pieces but does not alter its chemical composition.
14. A decaying leaf
- Chemical Change: Decay involves decomposition, where microorganisms break down the leaf, forming new substances.
15. Frying an egg
- Chemical Change: Frying an egg denatures the proteins, causing irreversible changes and forming new substances.
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#### Row 4
16. Mixing vinegar and baking soda
- Chemical Change: Mixing vinegar (acetic acid) and baking soda (sodium bicarbonate) produces carbon dioxide gas, water, and sodium acetate, forming new substances.
17. A rusting bike
- Chemical Change: Rusting is oxidation, where iron reacts with oxygen and water to form iron oxide (rust), a new substance.
18. Burning wood
- Chemical Change: Burning wood involves combustion, producing carbon dioxide, water, and ash, forming new substances.
19. Cutting grass
- Physical Change: Cutting grass changes its shape but does not alter its chemical composition.
20. Digesting food
- Chemical Change: Digestion involves breaking down food into simpler substances through chemical reactions in the body.
---
Here is the categorization:
| Activity | Type |
|------------------------------|---------------|
| Cutting an apple | Physical |
| Baking a cookie | Chemical |
| Lighting a match | Chemical |
| Melting ice | Physical |
| Roasting a marshmallow | Chemical |
| Freezing water | Physical |
| Burning a candle | Chemical |
| Dissolving sugar | Physical |
| Ripping paper | Physical |
| Slicing bread | Physical |
| Boiling water | Physical |
| Crushing a can | Physical |
| Breaking a mirror | Physical |
| A decaying leaf | Chemical |
| Frying an egg | Chemical |
| Mixing vinegar and baking soda | Chemical |
| A rusting bike | Chemical |
| Burning wood | Chemical |
| Cutting grass | Physical |
| Digesting food | Chemical |
$$
\boxed{\text{See the detailed explanation above for each activity.}}
$$
Definitions:
- Physical Change: A change in which the physical properties of a substance (e.g., shape, size, state) are altered, but the chemical composition remains the same.
- Chemical Change: A change in which the chemical composition of a substance is altered, resulting in the formation of new substances.
Solution:
Let's analyze each activity and categorize it as either a physical change or a chemical change.
---
#### Row 1
1. Cutting an apple
- Physical Change: The apple is being cut into pieces, but its chemical composition remains unchanged.
2. Baking a cookie
- Chemical Change: Baking involves heating, which causes chemical reactions (e.g., caramelization, Maillard reaction), changing the ingredients into a new substance (cookie).
3. Lighting a match
- Chemical Change: Lighting a match produces heat, light, and smoke, indicating a chemical reaction where new substances are formed.
4. Melting ice
- Physical Change: Melting is a phase change from solid to liquid, but the chemical composition of water (H₂O) remains the same.
5. Roasting a marshmallow
- Chemical Change: Roasting causes the sugar in the marshmallow to caramelize, forming new compounds through chemical reactions.
---
#### Row 2
6. Freezing water
- Physical Change: Freezing is a phase change from liquid to solid, but the chemical composition of water (H₂O) remains unchanged.
7. Burning a candle
- Chemical Change: Burning involves combustion, where wax reacts with oxygen to produce carbon dioxide, water, and heat, forming new substances.
8. Dissolving sugar
- Physical Change: Dissolving sugar in water separates the sugar molecules but does not change their chemical composition.
9. Ripping paper
- Physical Change: Ripping paper tears it apart physically without altering its chemical structure.
10. Slicing bread
- Physical Change: Slicing bread changes its shape but does not alter its chemical composition.
---
#### Row 3
11. Boiling water
- Physical Change: Boiling is a phase change from liquid to gas, but the chemical composition of water (H₂O) remains the same.
12. Crushing a can
- Physical Change: Crushing deforms the can physically but does not change its chemical composition.
13. Breaking a mirror
- Physical Change: Breaking a mirror shatters it into pieces but does not alter its chemical composition.
14. A decaying leaf
- Chemical Change: Decay involves decomposition, where microorganisms break down the leaf, forming new substances.
15. Frying an egg
- Chemical Change: Frying an egg denatures the proteins, causing irreversible changes and forming new substances.
---
#### Row 4
16. Mixing vinegar and baking soda
- Chemical Change: Mixing vinegar (acetic acid) and baking soda (sodium bicarbonate) produces carbon dioxide gas, water, and sodium acetate, forming new substances.
17. A rusting bike
- Chemical Change: Rusting is oxidation, where iron reacts with oxygen and water to form iron oxide (rust), a new substance.
18. Burning wood
- Chemical Change: Burning wood involves combustion, producing carbon dioxide, water, and ash, forming new substances.
19. Cutting grass
- Physical Change: Cutting grass changes its shape but does not alter its chemical composition.
20. Digesting food
- Chemical Change: Digestion involves breaking down food into simpler substances through chemical reactions in the body.
---
Final Answer:
Here is the categorization:
| Activity | Type |
|------------------------------|---------------|
| Cutting an apple | Physical |
| Baking a cookie | Chemical |
| Lighting a match | Chemical |
| Melting ice | Physical |
| Roasting a marshmallow | Chemical |
| Freezing water | Physical |
| Burning a candle | Chemical |
| Dissolving sugar | Physical |
| Ripping paper | Physical |
| Slicing bread | Physical |
| Boiling water | Physical |
| Crushing a can | Physical |
| Breaking a mirror | Physical |
| A decaying leaf | Chemical |
| Frying an egg | Chemical |
| Mixing vinegar and baking soda | Chemical |
| A rusting bike | Chemical |
| Burning wood | Chemical |
| Cutting grass | Physical |
| Digesting food | Chemical |
$$
\boxed{\text{See the detailed explanation above for each activity.}}
$$
Parent Tip: Review the logic above to help your child master the concept of physical or chemical change worksheet.
