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Lesson 6 of 7

Boiling and condensing

I can measure the boiling point of water and explain what happens to particles when a substance in the gas state condenses.

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Lesson 6 of 7
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Boiling and condensing

I can measure the boiling point of water and explain what happens to particles when a substance in the gas state condenses.

Lesson details

Key learning points

  1. The condensing point and boiling point are the same temperature for a substance, for water this is 100°C.
  2. Steam is water in the gas state.
  3. A substance increases in volume in the gas state when boiled.
  4. A substance decreases in volume in the liquid state when condensed.
  5. Particles move further apart when boiled and move closer together when condensed.

Keywords

  • Boiling - when a substance in the liquid state is heated, and gas bubbles are formed.

  • Boiling point - the temperature at which a substance changes from a liquid state to a gas state.

  • Condensing - when a substance in the gas state is cooled and changes to a liquid state.

  • Condensing point - the temperature at which a substance changes from a gas state to a liquid state.

Common misconception

Pupils tend to think that all gases are made of air. That gases contain no particles.

Ensure that pupils gain the knowledge that the particles are the substance and between the particles there is nothing.

Hold up each piece of equipment to make sure pupils are familiar with them. Demonstrate how to observe the thermometer.
Teacher tip

Equipment

Content guidance

  • Risk assessment required - equipment

Supervision

Adult supervision required

Licence

This content is © Oak National Academy Limited (2026), licensed on Open Government Licence version 3.0 except where otherwise stated. See Oak's terms & conditions (Collection 2).

Lesson video

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Prior knowledge starter quiz

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6 Questions

Q1.
Water in the solid state is called...

Correct Answer: ice

Q2.
Which of the following statements is true about particles in the gas state?

They are tightly packed.
They have fixed positions.
They are touching and move over and around each other.
Correct answer: They move randomly.

Q3.
Put the following states of matter in order of decreasing particle movement.

1 - Gas
2 - Liquid
3 - Solid

Q4.
What laboratory equipment is used to measure the boiling point of a substance?

Correct answer: thermometer
measuring cylinder
mass balance
stop watch

Q5.
What is in-between the particles in the gas state?

air particles
bigger gas particles as they have expanded
Correct answer: empty space
more gas particles that have been created to fill the space

Q6.
Place these processes in the correct order as they would occur when heating water.

1 - Water is in the liquid state.
2 - Water is heated.
3 - The temperature of the water reaches it's boiling point.
4 - Water begins to boil.
5 - Water is in the gas state.

Assessment exit quiz

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6 Questions

Q1.
What is the boiling point of water?

0°C
Correct answer: 100°C
50°C
-100°C

Q2.
Match the terms to the descriptions.

Correct Answer:Condensing point,The temperature at which condensing occurs.

The temperature at which condensing occurs.

Correct Answer:Boiling point,The temperature at which boiling occurs.

The temperature at which boiling occurs.

Correct Answer:Boiling,When particles change from the liquid to gas state.

When particles change from the liquid to gas state.

Correct Answer:Condensing,When particles change from the gas to the liquid state.

When particles change from the gas to the liquid state.

Q3.
What happens to the particles of a substance when it condenses?

They move further apart.
Correct answer: They move closer together.
They vibrate in fixed positions.
They stop moving.

Q4.
The volume of a substance when reaching its boiling point.

Correct Answer: increases, gets larger, gets bigger

Q5.
What is the relationship between the condensing and boiling points of a substance?

They are different temperatures.
The condensing point is higher than the boiling point.
Correct answer: They are the same temperature.
The boiling point is higher than the condensing point.

Q6.
Select the correct statements that describe what happens during boiling.

Correct answer: Particles move further apart.
Correct answer: The volume of the substance increases.
The particles become larger.
Particles start to align in a fixed pattern.
The temperature of the substance decreases.

Lesson appears in

UnitScience / Solid, liquid, gas states and changes of state

Science

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