Students classify objects as a solid, liquid or gas and begin to develop a shared understanding of the observable properties of each state.
Explain to the students that they will be learning about the observable properties and behaviours of solids, liquids and gases.
Organise the class into groups of three.
Ask each group to complete the following statements based on their current understandings.
- A solid is …
- A liquid is …
- A gas is …
Meet together as a class and share understandings. Ask students what they think are the key properties and behaviours of solids, liquids and gases. Create a class list of these properties and behaviours. (This list can be added to and modified as more information and understanding is gathered throughout the unit.)
Introduce the word ‘matter’ to the class and explain that solids, liquids and gases are three different states of matter. Ask students what they think the word ‘matter’ means from a scientific point of view.
- Introduce the students to the ‘mystery bag’ and explain that inside the bag are various items that you would like them to classify as a solid, a liquid or a gas.
- Hold up a solid item from the mystery bag and ask the students to write down the item’s state (or states) of matter.
- Ask them to share their thoughts with a partner and to explain their thinking. Why do they think it is a solid? What features does it have? Ask them to be as specific as possible. For example, a can of soft drink could be classified as a solid if you are focusing on the can or a liquid if you are focusing on its contents. It also contains gas within the liquid.
- Repeat this process with the remaining items in the mystery bag.
- As a class discuss any items that the students had difficulty classifying or items that they disagreed with the classification.
View animations 2 (Solids), 3 (Liquids) and 6 (Gases) on the web page The properties of solids, liquids and gases to help students revise the features of these states of matter. Revise the differences between them.
Revisit the list of the observable properties of solids, liquids and gases created at the start of the lesson and ask the students to make any changes or additions.