Let's analyze each image in the worksheet and determine whether the change shown is
physical or
chemical, based on the definitions provided:
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🔹 1. Crumpled Aluminum Can
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Image: A crushed aluminum can.
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Change Type: Physical Change
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Why? The shape of the can has changed, but the material (aluminum) remains the same. It can be flattened again or recycled into a new can. No new substances are formed.
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✔ Answer: Physical change — only the shape changes; no new substance is created.
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🔹 2. Cooking an Egg (Frying an Egg)
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Image: An egg frying in a pan.
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Change Type: Chemical Change
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Why? When an egg is cooked, the proteins denature and coagulate, forming a solid. This change cannot be reversed. The raw egg cannot be restored from the cooked one. Also, there’s a color change and texture change, which are signs of chemical change.
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✔ Answer: Chemical change — the egg undergoes irreversible changes due to heat, forming new substances.
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🔹 3. Rusty Iron Pipe
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Image: A rusted metal pipe.
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Change Type: Chemical Change
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Why? Rusting is a reaction between iron and oxygen in the presence of moisture, forming iron oxide (rust). This process cannot be easily reversed. The original iron is chemically altered.
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✔ Answer: Chemical change — rusting creates a new substance (iron oxide), which is irreversible.
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🔹 4. Butter Melting on Toast
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Image: Butter melting on a slice of toast.
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Change Type: Physical Change
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Why? The butter changes from solid to liquid due to heat, but it remains butter. If cooled, it will solidify again. No new substances are formed.
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✔ Answer: Physical change — only the state changes; composition stays the same.
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🔹 5. Broken Green Circle (Cut Apple?)
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Image: A green circle cut into pieces (possibly representing a sliced apple).
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Change Type: Physical Change
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Why? The object is simply divided into smaller parts. The material hasn’t changed chemically. If it were an apple, slicing it doesn't change its chemical makeup (though oxidation may occur later, but that's not shown here).
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✔ Answer: Physical change — cutting or breaking does not alter the substance’s chemical identity.
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✔ Final Answers Table:
|
Change |
Is it physical or chemical? Why? |
|-----------|--------------------------------------|
| Crumpled can |
Physical — Only shape changes; no new substance formed. |
| Frying egg |
Chemical — Proteins change irreversibly; new substances form. |
| Rusty pipe |
Chemical — Iron reacts with oxygen to form rust (iron oxide). |
| Butter melting |
Physical — State change from solid to liquid; reversible. |
| Cut green circle |
Physical — Only size/shape changes; no chemical alteration. |
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📝 Summary:
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Physical changes: Reversible, involve changes in state, shape, or size without altering chemical composition.
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Chemical changes: Irreversible, involve formation of new substances, often with color change, gas production, or odor.
This worksheet helps students distinguish between these two types of changes using real-life examples.
Parent Tip: Review the logic above to help your child master the concept of physical changes of matter worksheet.
