Outline of unit

Everything around us is made of matter. Matter commonly exists as solids, liquids or gases. Substances can be classified as a solid, liquid or gas based on their observable properties and behaviours. Matter can be changed from one state to another by adding or removing heat. This can be seen in everyday situations such as a liquid turning to a solid when water is put in the freezer, a liquid turning to a gas when water is boiled in a kettle and a solid turning to a liquid when ice cubes are left in the sun.

This unit builds on student understandings of the properties of solids and liquids developed in year 3 science before looking more specifically at the observable properties and behaviours of gas, how we use gas in our everyday lives and some of the safety implications of this. Students work in cooperative learning teams to explore how adding and removing heat can impact on these properties and result in changes to the states of matter. Through class discussions, group tasks and scientific investigations, students develop an understanding of how the observable properties and behaviours of these states of matter are used to help classify substances and why some substances are difficult to classify.

Australian Curriculum content descriptions

Science Understanding

Chemical sciences

Solids, liquids and gases have different observable properties and behave in different ways (ACSSU077

Science as a Human Endeavour

Nature and development of science Science involves testing predictions by gathering data and using evidence to develop explanations of events and phenomena (ACSHE081

Science Inquiry Skills

Questioning and predicting

With guidance, pose questions to clarify practical problems or inform a scientific investigation, and predict what the findings of an investigation might be (ACSIS231

Planning and conducting

With guidance, plan appropriate investigation methods to answer questions or solve problems (ACSIS086

Decide which variable should be changed and measured in fair tests and accurately observe, measure and record data, using digital technologies as appropriate (ACSIS087

Processing and analysing data and information

Construct and use a range of representations, including tables and graphs, to represent and describe observations, patterns or relationships in data using digital technologies as appropriate (ACSIS090

Compare data with predictions and use as evidence in developing explanations (ACSIS218


Suggest improvements to the methods used to investigate a question or solve a problem (ACSIS091


Communicate ideas, explanations and processes in a variety of ways, including multi-modal texts (ACSIS093

Source: Australian Curriculum, Assessment and Reporting Authority (ACARA). 

Achievement standard

This lesson sequence provides opportunities to gather information about students’ achievement of specific components in the standards (which are bolded in the statements below).

By the end of Year 5, students classify substances according to their observable properties and behaviours. They explain everyday phenomena associated with the transfer of light. They describe the key features of our solar system. They analyse how the form of living things enables them to function in their environments. Students discuss how scientific developments have affected people’s lives and how science knowledge develops from many people’s contributions.


Students follow instructions to pose questions for investigation, predict what might happen when variables are changed, and plan investigation methods. They use equipment in ways that are safe and improve the accuracy of their observations. Students construct tables and graphs to organise data and identify patterns. They use patterns in their data to suggest explanations and refer to data when they report findings. They describe ways to improve the fairness of their methods and communicate their ideas, methods and findings using a range of text types.

Source: Australian Curriculum, Assessment and Reporting Authority (ACARA). 

Ice cubes, Muffet, CC BY 2.0; Steam train, Capt' Gorgeous, CC BY 2.0; Water being poured from jug, theowl84, CC BY 2.0.

Additional information for teachers


Background information (PDF, 494 KB)

Safety advice (PDF, 352 KB)

Materials and equipment (PDF, 427 KB)