New
New
Year 4

Changing state: liquid to gas

I can observe water change from the liquid state to the gas state.

New
New
Year 4

Changing state: liquid to gas

I can observe water change from the liquid state to the gas state.

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Lesson details

Key learning points

  1. Water in the liquid state can change into water in the gas state (water vapour).
  2. In its gas state, water is invisible, can flow, has no fixed volume and takes the shape of the whole of its container.
  3. The process in which a liquid changes to a gas is called evaporation.
  4. Water can be observed changing from liquid to gas.
  5. We can change the state of a liquid to a gas by heating.

Keywords

  • Liquid - A liquid can flow, has a fixed volume and takes the shape of the bottom its container.

  • State - Materials can exist in three common states of matter: solid, liquid and gas.

  • Gas - A gas can flow, has no fixed volume and takes the shape of the whole of its container.

  • Water vapour - Water is called water vapour when it is in the gas state.

  • Evaporation - Evaporation is the change of state from a liquid to a gas.

Common misconception

Water cannot exist in a gas form.

Teaching slides explain that water can exist as gaseous water vapour and the process of evaporation.

When discussing evaporation, encourage children to avoid explanations suggesting that water (liquid) has disappeared but rather that it is still present but has changed state into water vapour (gas).
Teacher tip

Equipment

Equipment to carry out evaporation: either a shallow container and access to sunshine, a radiator, or an oil burner.

Content guidance

  • Risk assessment required - equipment

Supervision

Adult supervision required

Licence

This content is © Oak National Academy Limited (2024), 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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6 Questions

Q1.
Which of these are states of matter?
Correct answer: liquid
air
water
Correct answer: solid
Correct answer: gas
Q2.
Match the state to the characteristics.
An image in a quiz
Correct Answer:solid,does not take the shape of its container

does not take the shape of its container

Correct Answer:liquid,takes the shape of the bottom of its container

takes the shape of the bottom of its container

Q3.
What name is given to the temperature at which a solid changes to a liquid?
An image in a quiz
Correct Answer: melting temperature
Q4.
Different materials have __________ melting points.
the same
Correct answer: different
identical
Q5.
Materials in the state are often invisible and have no fixed shape or volume.
Correct Answer: gas, gaseous
Q6.
Match the process to the action that causes it to happen.
An image in a quiz
Correct Answer:melting,heat ice (solid sate water)

heat ice (solid sate water)

Correct Answer:freezing,cool liquid water

cool liquid water

6 Questions

Q1.
Water in the gas state is called water .
Correct Answer: vapour, steam, vapor
Q2.
Which scientific skill would you be using if you watched water changing state?
prediction
Correct answer: observation
planning
evaluating
Q3.
What would you need to change to cause a liquid to become a gas?
An image in a quiz
container
colour
Correct answer: temperature
Q4.
In which state can materials flow?
An image in a quiz
solid
Correct answer: liquid
Correct answer: gas
Q5.
Which of these statements are true about water vapour?
Correct answer: It is a gas.
It is a liquid.
Correct answer: It can flow.
Q6.
What is the name of the process in which a liquid changes to a gas?
An image in a quiz
melting
Correct answer: evaporation
gassing

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