Activity Introduction

Quick summary: Students investigate how recyclable material is sorted by applying some of their known properties. They focus on the science behind sorting at a MRF – Materials Recovery Facility. Students explain the entire loop for an aluminium can.    

This lesson has been developed as part of the Schools Recycle Right Challenge for Planet Ark’s National Recycling Week. Register your lesson or other activities so they can be counted towards the national achievement and to receive other free support materials.


Learning intentions: 

  • Students build an understanding of the differences amongst elements, compounds and mixtures. 
  • Students explore how properties of matter can help in separating mixtures.
  • Students learn about the processes of aluminium recycling.

21st century skills: 

  CommunicatingCritical Thinking   

Australian Curriculum Mapping

Year 8 Science:

  • Differences between elements, compounds and mixtures can be described at a particle level (ACSSU152)
  • Summarise data, from students’ own investigations and secondary sources, and use scientific understanding to identify relationships and draw conclusions (ACSIS145)
  • 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 (ACSIS146)

Syllabus OutcomesSC4-7WS, SC4-6WS, SC4-16CW

Year level: 8

Time needed: 50 minutes

Level of teacher scaffolding: High – The experiments will need to be set up. Most students will need to be constantly asked leading questions if they are able to make the link between the experiments and the scientific principles. Magnetising aluminium is difficult to explain.

Resources needed: Magnets, clean steel and aluminium cans, a variety of plastics cut in squares, a few items of paper and glass cu, water, salt (NaCl), beakers.

Digital technology opportunities: Locate specific information from their local council website.

Assumed prior learning: Familiar with the plastics number code, have used magnets to find out which materials are attracted to them. 

Keywords: Mixture, magnetic, magnetic field, electricity, solution, salt, buoyancy, density, furnace, contamination.


Cool Australia’s curriculum team continually reviews and refines our resources to be in line with changes to the Australian Curriculum.

These Planet Ark resources were developed by Cool Australia with funding from the Alcoa Foundation.


Teacher Worksheet

Teacher Preparation

Overarching learning goals: Student explore the large scale problem of separating mixtures. They investigate some separation techniques used to recycle materials using the chemical properties of materials and demonstrate how the loop is closed when aluminium is recycling.  

Teacher content information: Most of Australia's recycling materials are picked up from the kerbside from dedicated recycle wheelie bins provided to each home. The collected material must then be sorted and bailed up to be transported to different recycling factories.

The sorting process needs to be achieved so that the materials are not contaminated with other materials.

The easiest material to extract is steel cans. A powerful magnet will extract all the large steel items. Under normal conditions aluminium is not magnetic. Metals that are attracted by a magnet do so because the outer electrons of the atoms line up. However if a magnet is moving, then aluminium and some other non-magnetic me

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Student Worksheet

Thought starters: What would you do if you made a drink of cordial that tastes too strong? Can you separate the water and cordial? 

Step 1: Introduction to sorting waste 

Sorting Your Recycling - Video 1

1. Recall what materials are being sorted at the MRF - Materials Recovery Facility?

Experiment 1 - Materials attracted to a magnet 

Which materials are attracted to a magnet?

Material Magnetic Non-magnetic
Steel cans
Aluminium cans

How can this be used to sort waste?

Experiment 2 – Making an aluminium can move 

1. Touch the magnet against an aluminium can. What happens?

2. Lay the can on its side so the lid faces you. Move the magnet back and forth over the can. Did the can react?

3. Try to move the magnet faster. Did the can have a stronger reaction?

4. How is magnetism different for aluminium compared with steel?

Experiment 3 – Plastics sink or swim A

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