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Let's teach! Primary

Lesson 2

Can states of matter be changed?

Lesson Plan

Preparation

Content focus: How solids, liquids and gases can be changed

Investigative skills focus: 

Questioning and predicting

Planning and conducting

Processing and analysing data and information evaluating

Communicating

Collect all the materials required for the experiments on the experiment page.

Introduction

Background information

  • Some changes of matter are physical (reversible). They can change appearance or state through bending, heating, stretching etc. but are still the same material and can be changed back. (Sometimes this is a complex process, such as those dealing with evaporation to extract salt that has been dissolved in water.) Other changes can be chemical (irreversible). Through heating, burning, cooking etc., a new substance is made and cannot be changed back.
  • The temperature at which a solid turns into a liquid is called the melting point; the temperature at which a liquid turns into a gas is called the boiling point.
  • A gain in heat by a state of matter is called an endothermic change; a loss in heat is called an exothermic change.
  • Most substances follow the normal changes of state when they are heated (i.e. from solid to liquid to gas) and the reverse if they are cooled. A few can move directly from solid to gas, without becoming a liquid first. This is the process called sublimation (as shown on the diagram on page 39). Dry ice (solid carbon dioxide) is a good example of this process. Mothballs and some types of solid air fresheners are also examples. The reverse of sublimation is deposition.

Development

  • Allow the pupils to read the text on student page slides independently, but assist with unknown vocabulary if necessary.
  • Discuss the text when they have finished reading it to ensure they understand the concepts presented.

Differentiation

  • The artworks created by completing the activities using evaporated coloured water can be used to create sun catchers or hanging decorations. Cut into shapes, punch a hold at the top and hang using string.

Conclusion

  • Discuss with the students after the activity how the experiment worked or didn’t work, what might have gone wrong, and what they would change to make it better.

Assessment

Page 40

    1. (a) matter, (b) molecules/atoms, (c) solid, (d) liquid, (e) gas
    2. Heat, when applied, makes the molecules speed up; cold makes the molecules slow down.
    3. (a) When heat is applied to a solid, the molecules speed up and the forces between them become weaker. The molecules separate and form a liquid.
      (b) When a gas is cooled, the molecules slow down and the forces among them increase. The molecules move closer together to form a liquid. As the temperature continues to decrease, the molecules in the liquid move even closer together to form a solid.
    4. Starting state: solid, liquid, gas, liquid
      Changed state: liquid, solid, liquid, gas
      Name of process: melting, freezing, condensation, evaporation

The work of scientists question
Use and influence of science
Answers will vary. The pupils could list wood or coal as solid forms of heating and cooking in the home and natural gas as another. (Electrical forms of heating and cooking cannot be included in any of the categories since they are a force rather than a state of matter.) Some pupils might include safety or environmental issues relating to the use of wood, coal and gas for heating and cooking in the home. These should be considered as a class.

 

Student Pages

Science Year 5 Unit 2 Lesson 2 Intro 1
Lesson 2
Can states of matter be changed?
Science Year 5 Unit 2 Lesson 2 Intro 2
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Lesson 2
Can states of matter be changed?
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Science Year 5 Unit 2 Lesson 2 Slide 1 - copy - copy

Can the heating process accelerate the evaporation of water?

Let's explore this question with a virtual experiment.

Science Year 5 Unit 2 Lesson 2 Slide 1 - copy
Science Year 5 Unit 2 Lesson 2 Slide 1 - copy - copy - copy

Now we have seen what the heating process can do to accelerate the evaporation of water, let's explore this concept further...

Science Year 5 Unit 2 Lesson 2 Slide 1

Matter is anything that takes up space and has mass.

It is made up of small particles called molecules (which are made of atoms) held together by electric forces.

Science Year 5 Unit 2 Lesson 2 Slide 2

Among the particles are empty spaces which allow the particles to move about.

They move constantly - the amount of movement depends on the amount of space among the particles.

Science Year 5 Unit 2 Lesson 2 Slide 3

LT Chemical Sciences Data Lesson 2

The particles in solids, which are packed closely together, cannot move about very much; those in liquids, which are further apart, can move around the most.

Science Year 5 Unit 2 Lesson 2 Slide 4

Materials can change from one state to another if temperature is applied or removed.

Science Year 5 Unit 2 Lesson 2 Slide 5

When heat is applied, a material will normally change from a solid to a liquid to a gas; when a material is cooled, it will normally change from a gas to a liquid to a solid.

Science Year 5 Unit 2 Lesson 2 Slide 6

Why and how does this happen?

Science Year 5 Unit 2 Lesson 2 Slide 7

When energy, in the form of heat, is applied to a state of matter, the movement of the molecules increases and the forces holdin them together become weaker.

Science Year 3 Unit 1 Lesson 1 Slide 8

If the state of matter is a solid, the molecules separate and form a liquid.

As more heat is added, the movement of the molecules increases.

Science Year 5 Unit 2 Lesson 2 Slide 9

When heat energy is decreased by cooling, the movement of the molecules decreases and the forces holding them together increase in strength.

Science Year 5 Unit 2 Lesson 2 Slide 10

If the state of matter is a gas, where the molecules are far apart, they will move more slowly and move closer together, and form a liquid.

As the matter is cooled further, the molecules slow down even more and form a solid.

LT Chemical Sciences Data Lesson 2

Science Year 5 Unit 2 Lesson 2 Slide 11

Water is an easy form of matter to use to demonstrate changing states.

Science Year 5 Unit 2 Lesson 2 Slide 12

When liquid water is heated to boiling point, it forms water vapour which is a gas.

LT Chemical Sciences Data Lesson 2

Science Year 5 Unit 2 Lesson 2 Slide 13

When liquid water is cooled by freezing, it forms ice which is a solid.

When ice is melted, it forms liquid water.

Science Year 5 Unit 2 Lesson 2 Final Slide
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Student Summary

Summary of student page information

Worksheet

Activities for students to complete

Experiment Worksheet

An experiment to consolidate learnings

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