To solve the problem, we need to determine whether each example represents a
physical change or a
chemical change. Here's a breakdown of each scenario:
Definitions:
-
Physical Change: A change in which the physical properties of a substance (such as 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 with different properties.
Analysis of Each Example:
1.
An ice cube melts
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Explanation: When an ice cube melts, it changes from a solid to a liquid state. The water molecules rearrange themselves but do not form new substances.
-
Type: Physical Change
2.
Rust forms on a car
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Explanation: Rusting is a chemical reaction where iron reacts with oxygen and water to form iron oxide (rust). This creates a new substance with different properties.
-
Type: Chemical Change
3.
A glass bottle breaks
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Explanation: Breaking a glass bottle only changes its shape and structure; the glass material itself does not change chemically.
-
Type: Physical Change
4.
A sheet of paper is cut in half
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Explanation: Cutting a sheet of paper changes its size and shape but does not alter its chemical composition.
-
Type: Physical Change
5.
An apple is cut
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Explanation: Cutting an apple changes its shape but does not alter its chemical composition.
-
Type: Physical Change
6.
A log burns at a campfire
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Explanation: Burning wood involves a chemical reaction where wood combines with oxygen to produce carbon dioxide, water vapor, and heat. New substances are formed.
-
Type: Chemical Change
7.
Make yogurt
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Explanation: Making yogurt involves bacteria breaking down lactose in milk into lactic acid, which changes the chemical composition of the milk.
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Type: Chemical Change
8.
Rotten apple
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Explanation: Rotten apples involve decomposition, where microorganisms break down the apple's organic matter, forming new substances.
-
Type: Chemical Change
Final Answers:
1. An ice cube melts →
Physical Change
2. Rust forms on a car →
Chemical Change
3. A glass bottle breaks →
Physical Change
4. A sheet of paper is cut in half →
Physical Change
5. An apple is cut →
Physical Change
6. A log burns at a campfire →
Chemical Change
7. Make yogurt →
Chemical Change
8. Rotten apple →
Chemical Change
Summary:
-
Physical Changes: 1, 3, 4, 5
-
Chemical Changes: 2, 6, 7, 8
$$
\boxed{
\text{Physical Change: 1, 3, 4, 5} \quad \text{Chemical Change: 2, 6, 7, 8}
}
$$
Parent Tip: Review the logic above to help your child master the concept of changes in matter worksheet.
