What is the difference between a solid, a liquid and a gas?

Preparation

• Obtain the items mentioned in the first few paragraphs of the student summary: a book, a bottle of glue, a ruler, a cup of water, a chair and a blow-up balloon.
• Collect the equipment needed for the investigation sheet: a basketball, netball or football could be used. The bicycle pump can be used to remove the air from the ball if it is already inflated.

Curriculum links

• Australian Curriculum: ACSSU046, ACSHE050, ACSIS215, ACSIS058, ACSIS060
• NSW Curriculum: ST2-6MW-S, ST2-4LW-S, ST2-1WS-S
• Victorian Curriculum: VCSSU056, VCSSU059, VCSIS070, VCSIS071, VCSIS072
• WA Curriculum: ACSSU046, ACSHE050, ACSIS215, ACSIS058, ACSIS060

Suggested teaching strategies

• Collaborative learning

Introduction

• The student summary and worksheet should be used together. Ensure students understand the meaning of the word ‘properties’.
• Display the items mentioned in the first paragraph of the student pages. Place them in various locations around the classroom so students will easily see them. The answers have been provided in the assessment section.
• The student summary and worksheet should be used together.

Development

• Provide students with printable versions of the student summary and worksheet. Have students complete the worksheet.

Differentiation

• Students could work in pairs or a small group to complete the experiment worksheet. However, ensure that all have the opportunity to weigh and heft the materials, rather than simply copy the measurements or observations of other students.

Conclusion

• After discussing their observations from the investigation sheet, talk about whether any parts of the activity could be improved; e.g. scales not being sensitive enough to register weight, ball not being fully inflated.

Assessment

Student summary answers

Most children will not give ‘gas’ for an answer. Many will say ‘liquid’ because when sand is dry, it purs out of a container like a liquid. The answer is ‘solid’. Each little grain of sand is a solid. The same happens when you pour cereal out of a packet. But each piece of cereal is also a solid.

Worksheet answers

1. Matter is anything that takes up space and has mass (weight).
2. (a) liquid, (b) gas, (c) solid, (d) liquid
3. They all have mass/They all take up space
4. (a) Yes, (b) No, (c) No, (d) No, (e) No, (f) Yes
5. (a) packed together tightly, hardly move, (b) close together, always moving around each other, (c) far apart, spread out to fill up the space
6. Possible answers: sugar, flour, rice, nuts, pepper

Science as Human Endeavour question

Possible answers: car tyre, bike tyre, gas over, gas barbecue, bicycle pump, gas hot plates, gas hot water system

Investigation sheet answers

1. Students should say the cup is light/hardly weighs anything. Its weight should just register on the scales.
2. Students should predict the cup would feel heavier and measuring will prove that.
3. Measuring will show the cup with the solid (eraser) is heavier.
4. The inflated ball will be slightly heavier than the deflated ball because it is now filled with air.
5. Answers should indicate that solids, liquids and gases have weight.