Teaching Sequence

Work through this resource material in the following sequence:

10 minutes

Tune In: What are the properties of glass?

20 minutes

Find Out: Why do we need to separate materials to recycle them?

25 minutes

Take Action: Improving the recycling process

5 minutes

Reflection

Learning Intentions and Success Criteria

Students will:

consider how the properties of materials influence the separation methods used in a glass recycling plant.

Students can:

summarise how the properties of materials influence the separation methods used in a glass recycling plant
recommend solutions to improve the efficiency of the glass recycling process.

Tune In: What are the properties of glass?

Step 1

Provide students with pieces of the following recyclable materials in groups. (If these materials are not available, images of the materials can be found on the attached visual explainer). Explain to students that there are different forms of recycling bins. However, the most common one we tend to see is the yellow bin, where all of these recyclable materials are mixed together. To recycle each material, they need to be separated from each other.

Green glass	Clear glass	Amber glass	Cardboard
Paper	Aluminium foil	Soft drink cans	Food cans
Soft plastic	Hard plastic

As students examine the materials, ask them to observe and note down the properties of each material using the following categories:

colour
opaque, transparent or translucent
hardness
flexibility
density
texture
any other observations.

Step 2

Once your students have finished their observations, conduct a class discussion, asking them how they think these materials could be separated in order to be recycled.

Lead students to understand that the properties of the materials allow scientists to work out ways of separating them from each other. There is too much material to be sorted by hand, and sometimes, it breaks up into small pieces, which makes this even more difficult. This means specific processes need to be designed to separate the materials from each other automatically.

Ask your students what properties they think are the most useful in separating these materials.

Suggested answer: Manual sorting through visualising, size, shape, weight, magnetism for some metals, colour.

Find Out: Why do we need to separate materials to recycle them?

Step 1

Invite students to explore the catalogue of recycled products that can be manufactured by Visy. As they look through the glass products, explain to them that when these glass bottles and jars are being re-manufactured, they cannot contain any contaminants. If you completed Lesson 1 in this unit, Physical and Chemical Properties of Glass, students will know this includes the different types of glass, such as ceramic, porcelain, window glass and mirrors. If any contaminant makes its way into the new bottles, it could become unstable and even explode.

Step 2

Also, discuss with your students the importance of colour in these products. What type of recycled glass could be used to create the new clear recycled bottles and jars?

Suggested Answer: If amber or green recycled glass were used to make the clear bottles, they would have a tinted colour.

Explain to your students that when using recycled materials to remanufacture, those materials need to be completely separated to be used effectively. Contaminants can ruin the final product and make it unstable, and using the wrong colours can completely alter the look of the end product.

Step 3

Ask your students what ways they know of recycling glass from their homes.

Suggested response: There is co-mingled recycling (commonly a yellow bin), where glass is mixed in with other recyclables, glass-only recycling bins and then the Container Deposit scheme, where people are given money to recycle their glass containers.

The yellow bin is where most recycled glass goes. Once it leaves your household, it goes to a Material Recovery Facility (MRF) where the recyclables are separated to be reused. Watch the video below with your students to get an idea of how the MRF works, as students watch, ask them to note down any separation methods they see being used and what property is being taken advantage of to aid in the separation.

Visy – what happens to your household recycling? (vimeo.com/884167547?share=copy)

Suggested responses:

Manual sorting	Workers rely on sight to remove items that shouldn’t be present.
Size, weight, shape	Machinery can sort items based on their size, weight and shape. Paper and cardboard would be lighter, while metals and glass would be heavier.
Optical sorting	Sensors recognise the colour of an item and sometimes even chemical composition to either let it through or reject it.
Magnetic sorting	Attracts magnetic materials such as steel.
Eddy currents	Specialised type of equipment that can sort non-magnetic metals such as aluminium and copper.

Step 4

Watch the following video with your students, showing how recycled glass bottles and jars are made.

Visy - How We Make Glass - (vimeo.com/563048506)

Once the video is finished, conduct a class discussion with your students about what they have seen in both videos using the following prompts:

What happens at each stage, and how do the properties of the materials help them be separated?
What are some of the benefits of this process?
- Reduce reliance on natural resources, keep materials out of landfill and use less energy.
Why would Visy want to invest in better sorting equipment to increase the amount of recycled materials in their jars and bottles?

Take Action: Improving the recycling process

Step 1

Explain to your students that the material that goes to the glass plant to be sorted and recycled comes from three different places. The Material Recovery Facility (where the yellow bin goes), household glass recycling bins, and the Container Deposit Scheme. The glass plant where this material goes can sort about 40 tonnes of material per hour (depending on the plant and the technology available).

Show your students photos of the streams on the attached visual explainer and discuss their initial observations of the three options. What do they notice about each stream? What surprises them the most?

Step 2

Allocate your students into pairs and invite them to make a list of the advantages and disadvantages of each stream of material, focusing on the ease of sorting and the ease for consumers to contribute to this type of stream. Some examples have been included below.

	Advantages	Disadvantages
Material Recovery Facility (MRF)	The easiest way to recycle. Most people have access to a yellow bin.	Contaminated, a lot of material needs to be sorted out.
Glass Bin	Cleaner stream, not as much contamination.	Not all councils have a glass bin, still have some unwanted materials that need to be sorted.
Container Deposit Scheme (CDS)	A highly clean stream of material, glass only.	Relies on people recycling through CDS, which takes time and commitment.

Step 3

Sorting out the recycling that comes to the glass beneficiation plant is an intensive process. To make sure the most recycled glass is going into new bottles and jars, this sorting process has to be 100% effective because any contaminants in the product will cause it to be defective.

Your students' task is to work out a way to improve the quality of a certain stream of recycling or persuade people to use a certain stream, all to ensure there is more good quality, sorted glass to be used in remanufacturing processes.

Students could focus on one of the following or their own idea!

Understanding how to use your yellow bin and the impacts of correct/incorrect recycling
Understand how to use your glass bin and the impacts of correct/incorrect recycling.
Persuade people to use CDS and the impacts of correct/incorrect recycling.

Encourage students to use their knowledge of the importance of separation of the materials, what happens at each step of the process, and what positive impacts there could be when the recycled material streams are of better quality.

Reflection

Reflect on this lesson with your students using the 3-2-1 method. Ask students to write down

3 things they learned
2 fun facts
1 question they still have

Visy Glass - Separation of Mixtures: Glass Recycling

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Visy Glass - Separation of Mixtures: Glass Recycling

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Summary

Lesson Guides and Printables

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