Year 7 · Science · Particles and states of matter · Lesson 2

Changes of state

Changes of state - melting, freezing, boiling, evaporating, condensing and subliming - explained with particles, energy and a heating curve for water.

17-minute video lesson

Teaching, worked examples and 20 practice questions solved step by step.

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What your child will learn

Name the changes of state
Explain them using particles
Compare boiling and evaporation
Interpret a heating curve

The method

Name it.
Heat or cool?
Gain / lose energy.
New arrangement.

Key words: melting, freezing, boiling, evaporation, condensation, sublimation.

Worked examples

The first three practice questions from the lesson, with every step.

Question 1

What is melting?

Step 1: S → L

Answer: solid to liquid

Question 2

What is freezing?

Step 1: L → S

Answer: liquid to solid

Question 3

What is boiling?

Step 1: L → G

Answer: liquid to gas, at the boiling point