Outline of unit

The Earth is a planet of mixtures. Most of the substances that make up the land, water and air are mixtures. The food we eat and even our bodies are mixtures of different substances. Sometimes we want to combine different substances to make a mixture, for example adding milk to cereal, while at other times we want to separate mixtures, for example straining rice or producing clean drinking water.

In this unit students investigate different mixtures and separation techniques. They will apply their understanding of separation techniques to their daily lives. Students consider how people in different occupations use separation techniques.

Students explore the water cycle and investigate how humans have mimicked natural separation techniques to produce clean water for drinking. They will consider the need for sustainability of water.

Students will have opportunities to plan and conduct investigations and analyse results. They will evaluate their experimental methods and suggest how the method could be improved to achieve better results. They have opportunities to investigate issues surrounding the filtration and treatment of water in the community demonstrating how science and technology find solutions to the issue of water pollution.

Cross curriculum priority


Australian Curriculum content descriptions

Science Understanding

Chemical sciences

Mixtures, including solutions, contain a combination of pure substances that can be separated using a range of techniques (ACSSU113)

Earth and space sciences

Some of Earth’s resources are renewable, including water that cycles through the environment, but others are non-renewable (ACSSI116)

Science as a Human Endeavour

Use and influence of science

Science and technology contribute to finding solutions to a range of contemporary issues; these solutions may impact on other areas of society and involve ethical considerations (ACSHE120)

People use science understanding and skills in their occupations and these have influenced the development of practices in areas of human activity (ACSHE121)

Science Inquiry Skills

Planning and conducting

Collaboratively and individually plan and conduct a range of investigation types, including fieldwork and experiments, ensuring safety and ethical guidelines are followed (ACSIS125)

Processing and analysing data and information

Construct and use a range of representations, including graphs, keys and models to represent and analyse patterns or relationships, including using digital technologies as appropriate (ACSIS129)

Summarise data, from students’ own investigations and secondary sources, and use scientific understanding to identify relationships and draw conclusions (ACSIS130)


Reflect on the method used to investigate a question or solve a problem, including evaluating the quality of the data collected, and identify improvements to the method (ACSIS131)


Communicate ideas, findings and solutions to problems using scientific language and representations using digital technologies as appropriate (ACSIS133)

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 7, students describe techniques to separate pure substances from mixtures. They represent and predict the effects of unbalanced forces, including Earth’s gravity, on motion. They explain how the relative positions of the Earth, sun and moon affect phenomena on Earth. They analyse how the sustainable use of resources depends on the way they are formed and cycle through Earth systems. They predict the effect of environmental changes on feeding relationships and classify and organise diverse organisms based on observable differences. Students describe situations where scientific knowledge from different science disciplines has been used to solve a real-world problem. They explain how the solution was viewed by, and impacted on, different groups in society.

Students identify questions that can be investigated scientifically. They plan fair experimental methods, identifying variables to be changed and measured. They select equipment that improves fairness and accuracy and describe how they considered safety. Students draw on evidence to support their conclusions. They summarise data from different sources, describe trends and refer to the quality of their data when suggesting improvements to their methods. They communicate their ideas, methods and findings using scientific language and appropriate representations.

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

Muesli in bowl, © Purestock/SuperStock/Corbis; Salad dressing, © David Munns/Science Photo Library; Rainbow salad, © Adam Hart-Davis/Science Photo Library; Ghana, guinea worm, girls filtering water, © Louise Gubb/Corbis.

Additional information for teachers


Background information (PDF, 908 KB)

Safety advice (PDF, 339 KB)

Materials and equipment (PDF, 400 KB)


Developing programs in science for gifted and talented students 
(Australian Science Innovations)