Physical and Chemical Changes | ttroisi | Live - Free Printable

The image presents a grid of 20 different processes or actions, each illustrated with an image and a brief description. The task likely involves classifying these processes as either physical changes or chemical changes.

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🔬 Understanding the Concepts:

- Physical Change: A change in which the substance's form or state changes, but its chemical composition remains the same. No new substances are formed.
- Examples: cutting, melting, freezing, boiling, dissolving, crushing.

- Chemical Change: A change where new substances are formed due to a chemical reaction. The original substances are transformed into different ones.
- Examples: burning, rusting, cooking, digesting, rotting.

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✔ Let's classify each process:

| Image | Process | Type of Change | Reason |
|------|--------|----------------|-------|
| 1 | Cutting an apple | Physical | Only shape changes; no new substance formed. |
| 2 | Baking a cookie | Chemical | Heat causes chemical reactions (e.g., Maillard reaction), changing ingredients into a new substance. |
| 3 | Lighting a match | Chemical | Combustion occurs – new substances (like CO₂ and ash) form. |
| 4 | Melting ice | Physical | Water changes from solid to liquid, but it’s still H₂O. |
| 5 | Roasting a marshmallow | Chemical | Sugar caramelizes and burns – color and taste change due to chemical reactions. |
| 6 | Freezing water | Physical | Liquid turns to solid; still H₂O. |
| 7 | Burning a candle | Chemical | Wax combusts, producing CO₂, water vapor, and soot. |
| 8 | Dissolving sugar | Physical | Sugar molecules disperse in water, but no chemical reaction occurs (can be reversed by evaporation). |
| 9 | Ripping paper | Physical | Paper is torn, but its chemical makeup stays the same. |
| 10 | Slicing bread | Physical | Just cutting; no chemical change. |
| 11 | Boiling water | Physical | Water changes from liquid to gas; still H₂O. |
| 12 | Crushing a can | Physical | Shape changes, but material is unchanged. |
| 13 | Breaking a mirror | Physical | Glass shatters, but no new substances form. |
| 14 | A decaying leaf | Chemical | Decomposition involves microbes breaking down organic matter into new substances. |
| 15 | Frying an egg | Chemical | Heat denatures proteins, creating new structures (solid white/yolk). |
| 16 | Mixing vinegar and baking soda | Chemical | Produces CO₂ gas, water, and salt – a visible reaction. |
| 17 | A rusting bike | Chemical | Iron reacts with oxygen to form iron oxide (rust). |
| 18 | Burning wood | Chemical | Combustion produces ash, CO₂, and water vapor. |
| 19 | Cutting grass | Physical | Grass is cut, but not chemically altered. |
| 20 | Digesting food | Chemical | Enzymes break down food into simpler molecules (e.g., starch → glucose). |

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📊 Summary Table:

| Physical Changes | Chemical Changes |
|------------------|------------------|
| Cutting an apple | Baking a cookie |
| Melting ice | Lighting a match |
| Freezing water | Roasting a marshmallow |
| Dissolving sugar | Burning a candle |
| Ripping paper | Boiling water |
| Slicing bread | Crushing a can |
| Breaking a mirror | A decaying leaf |
| Cutting grass | Frying an egg |
| Mixing vinegar and baking soda |
| A rusting bike |
| Burning wood |
| Digesting food |

> ⚠️ Note: While boiling water is typically physical, if you're considering the formation of steam (gas), it's still physical. But if it's part of a larger process (like cooking), it might involve chemical changes. Here, it's isolated, so physical.

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✔ Final Answer:

Classify each process as either a physical or chemical change based on whether new substances are formed.

- Physical Changes:
Cutting an apple, Melting ice, Freezing water, Dissolving sugar, Ripping paper, Slicing bread, Boiling water, Crushing a can, Breaking a mirror, Cutting grass

- Chemical Changes:
Baking a cookie, Lighting a match, Roasting a marshmallow, Burning a candle, A decaying leaf, Frying an egg, Mixing vinegar and baking soda, A rusting bike, Burning wood, Digesting food

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