Teaching sequence

Work through this resource material in the following sequence:

15 minutes

Tune In: What is a closed loop system?

20 minutes

Find Out: Contamination in a closed-loop system

20+ minutes

Take Action: Closed-loop life cycle model

5 minutes

Reflection

Learning intentions

Students will:

understand the concept of closing the recycling loop
recognise why that contamination is a risk to successful closed-loop systems.

Success criteria

Students can:

create a model to represent and compare the lifecycles of plastic bottles made from non-recycled materials with bottles made from recycled materials
communicate the value of closing the recycling loop.

Tune In: What is a closed-loop system?

Step 1

As a class, watch the following video:

What really happens to the plastic you throw away – Emma Bryce (youtube.com/watch?v=_6xlNyWPpB8)

Once complete, invite students to reflect on their reactions to the video:

What was the journey that bottle 1 took? What are the consequences of this journey?
Suggested answer: Sent to landfill. Consequences include taking up space and leachate contaminating ecosystems, taking 1000 years to decompose.
What was the journey that bottle 2 took? What are the consequences of this journey?
Suggested answer: Gets carried to the ocean and is drawn into the Great Pacific Garbage Patch. This results in harmful pollution that affects native wildlife and humans.
What was the journey that bottle 3 took? What are the consequences of this journey?
Suggested answer: The bottle was recycled and turned into new items.

Step 2

Now pose the following question:

After bottle 3 has been recycled and turned into a new item, is this the end of its story?

Engage students in a class discussion around this question, and through this discussion, lead them to the concept of ‘closing the loop’. What might this mean?

Explain:

'Closing the loop' in recycling refers to the process of reusing and recycling products without losing the material, which creates a circular life cycle for the product. In a closed-loop recycling system, products can be recycled and turned back into the same product or raw materials over and over again. This reduces the need for new raw materials, which can help reduce waste and pollution and minimise environmental impact. Instead of thinking of empty plastic bottles as waste, we can think of them as a resource; this is key to closing the loop. As long as we keep adding things like plastic bottles to the correct recycling bin, these resources can be used indefinitely.

Step 3

Distribute one copy of the Student Worksheet to each student and direct students to the following two simple life cycle models, explaining that the first shows how plastic bottles are made using raw materials, and the second shows how a closed-loop recycling system works:

Talk through each system, showing students where the inputs and outputs are, and discuss the potential advantages and disadvantages of each system based on the following points:

Energy - which system do you think would use more energy and why?
Water - which system do you think would require more water and why?
Waste - which system do you think would produce more waste and why?
Which system do you think is ‘cleaner’ and why?

Invite students to share their ideas with the class, and explain they will be exploring the answers to these questions in more detail throughout the rest of the lesson.

Find Out: Contamination in a closed-loop system

Step 1

Direct students to the Student Worksheet and invite them to complete a Think-Pair-Share around the following question:

What might be some of the risks to a closed-loop system in terms of plastic recycling (i.e. what things might cause problems to a system that is dependent on sourcing recycled materials)?

Students should first work independently to record their answers to this question in Column A of the table on the Student Worksheet. They can then team up with a partner to discuss their answers and record any new ideas arising from this discussion in Column B of the same table.

Once complete, invite students to share their ideas with the class and record these on the board. These could include:

no one puts anything in the recycling bin, so there are no resources to make new items
demand for items made of these resources declines, and we are left with piles of stuff no one wants
recycling streams get contaminated because people put the wrong things in the wrong bins or because sorting machines aren’t able to sort materials correctly.

Explain to students that they will now dig into these issues in more detail with a particular focus on contamination and clean recycling streams.

Step 2

Invite students to work in pairs to read through the Challenges in Plastics Recycling Fact Sheet to answer the following questions (also available on the Student Worksheet - suggested answers included below):

What do you think it means to have a clean recycling stream for plastics?
Suggested answer: A clean recycling stream could be one where all recycling materials are physically cleaned before entering the recycling stream, and where materials to be recycled are made from only one type of plastic.
What are some examples of challenges to a clean recycling stream for plastics?
Suggested answer: Food waste, mixed plastics, oil, liquids, lack of education, suitable facilities, cost etc.
How do you think contamination could affect a closed-loop plastics recycling system?
Suggested answer: Closed-loop systems rely on high-quality plastic products; if products are contaminated, then they can’t be recycled efficiently, and they threaten to contribute to downcycling.
What plastics recycling challenges can be addressed by individual consumers? Suggested answer: Cleaning waste items, being selective about the products you buy and trying only to buy products that you know can be recycled in your area or that are only made of one material, sharing what you learn about recycling in your area with others.
What role do you think product designers (those who design the plastic products and packaging that we use) should play in a closed-loop plastics recycling system?

Learning extension: Students requiring extension could conduct independent research to answer the following question:

Which types of plastic are most easily recycled around the world?

Suggested answer:

1. Polyethylene Terephthalate (PET) - The most recycled plastic in the world, making up about 55% of the total recycled plastic.

2. High-Density Polyethylene (HDPE) - 100% recyclable and used in many products, including milk bottles, laundry detergent, and hair care products.

3. Polypropylene (PP) - PP can be recycled fairly easily, but it contains many toxic substances.

Which ones are the hardest to recycle?

1. Soft plastics are often contaminated with food and made from multiple types of plastic that are hard to process. 2. Polystyrene (PS) is rarely recycled and is being phased out in Australia. It's difficult to recycle because of collection challenges and high recycling costs. It's also toxic and releases styrene into the air when burned.

Which plastic codes can be recycled in your area?

Once complete, invite students to share their answers with the class and use the suggested answers (above) to clarify any misunderstandings.

Take Action: Closed-loop life cycle model

Step 1

Students will work in groups to look at what is required to produce plastic bottles and will create a 3D model that shows the life cycle of a plastic bottle for a closed-loop system. The aim of the model is to illustrate to others the value of closing the loop. The model must demonstrate why clean recycling streams are vital to a closed-loop system, and should also include information about the physical materials, energy usage and water required throughout the production of plastic bottles in a closed-loop system.

The 3D life cycle model could be made from materials otherwise destined for the recycling bin and should show all the stages of the closed-loop recycling system for a plastic bottle. Students can base their models on this image:

You could also explain that this model comes from VISY, an Australian company that uses closed-loops systems to produce packaging materials.

The model (also available on the Student Worksheet) should:

show what a recycled plastic bottle is made from and how this compares to a non-recycled bottle
explain how much energy is used to make bottles in both systems
explain how much water is used to make bottles in both systems
demonstrate the waste that is produced in both systems
show what happens when the bottle reaches the 'end of its life' (is thrown away) in both systems
explain the problems of contamination and why this is so important to closed-loop systems
include annotations or labels
include a short (1-2 paragraphs) description of what a closed-loop system is and how this applies to plastic bottles - this could be presented alongside the model.

Step 2

Provide students with an opportunity to share their work with the class or a wider audience. Invite students to provide feedback to other students on their work using the 2 stars and a wish feedback strategy.

You could also consider engaging students in a discussion around the following:

Do you think the closed-loop system could be applied to other recyclable materials? Why or why not?
What do you think about swapping the word ‘waste’ for ‘resource’?
How could we reduce contamination of closed-loop systems (e.g. product labelling, better bins, education)?
What plastics recycling challenges can be addressed by individual consumers?
What role do you think product designers (those who design the plastic products and packaging that we use) should play in a closed-loop plastics recycling system?

Reflection

Students can work independently to respond to the following (also available on the Student Worksheet):

Think about your own recycling practices: what could you do to positively affect the recycling streams you contribute to?

Visy Education - Bottled a Better Way

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