Teaching sequence

Work through this resource material in the following sequence:

15 minutes

Tune In: What resources are required to make a plastic bottle?

20 minutes

Find Out: Plastic bottle production processes

25 minutes

Take Action: Reducing water in plastic production

5 minutes

Reflection

Learning intentions

Students will:

compare the water used to produce a new single-use plastic bottle to a recycled plastic bottle.

Success criteria

Students can:

explain how science can be used to develop new methods of plastic production that minimise water usage
create flow charts for new and recycled plastic production.

Tune In: What resources are required to make a plastic bottle?

Step 1

Distribute one copy of the Student Worksheet to each student. Refer them to the following image:

Using this image as a visual prompt, invite the class to work together to create a mind map around the following question: What do we already know about how new single-use plastic bottles are made?

If you have completed the previous lessons in this unit, prompt students to think of the physical materials and energy requirements you have already identified and then to expand their thinking further to other resources.

For example, your mind map could look like this:

Step 2

Explain to student that today we are going to focus on the water required to create plastic bottles. Pose the question, ‘How many litres of water do you think it might take to make 1 new 1.25-litre plastic water bottle?’

Invite students to guess! You could play the game ‘higher or lower’ to direct students to the answer. The answer is 5.3 litres!

Step 3

Now pose the questions:

Why do you think making a single-use plastic bottle takes so much water?
Do you think it would be much different for a bottle made of our recycled materials? Why or why not?

Ask a scribe to record student responses (which can be referred to later in the lesson). In the next part of the lesson, students will explore the answers to these questions.

Find Out: Plastic bottle production

Step 1

Students will now investigate and compare the water required for making single-use plastic bottles from raw materials and making them from recycled materials. They will do this by researching each process and recording the process as a flow chart on a piece of butcher's paper, with an emphasis on water usage throughout each process. The aim of using the butchers' paper is to create a working document that can be amended and updated as they conduct their research - it doesn’t need to look perfect, but it needs to be clear and legible.

Note: Before students start creating their flow charts, it might be useful to demonstrate how to create a flow chart based on a production process. You could use the example of creating paper from raw and recycled materials (use the Paper Production Examples to guide you). As you read through each text, you could create the related flow charts on the board (see the examples on the Paper Production Examples. You could leave your worked examples of the flow charts on the board to support students in creating their plastic bottle flow charts.

Step 2

Depending on the time available, you could:

Break the class into small groups or pairs and give each group 2 pieces of butcher’s paper and some markers. They could label one paper as ‘new’ and the other as ‘recycled’, and each group could create a flow chart for each process.
Break the class into small groups or pairs and give each group 1 piece of butcher’s paper and some markers. They could label the paper as either ‘new’ or ‘recycled’, with each group creating a flow chart for 1 process.

Students can use the following websites to help them begin their research (also available on the Student Worksheet). Links marked with a * are suitable for students requiring support:

Water Footprint Network - What is a water footprint?(waterfootprint.org/water-footprint-2/what-is-a-water-footprint/)
Food Print - The Water Footprint of Your Plastic Bottle (foodprint.org/blog/plastic-water-bottle/)
Life of a Plastic Bottle (YouTube video) (youtube.com/watch?v=erGnf7ws20E)
Sydney Water - Life Cycle of a Plastic Bottle (sydneywater.com.au/content/dam/sydneywater/documents/education/life-cycle-of-a-plastic-bottle.pdf)
*Sydney City Rubbish - Life Cycle of a Plastic Bottle in Australia (sydneycityrubbish.com.au/the-life-cycle-of-a-plastic-bottle-in-australia/)
*Recycle Rally - What Is the Life Cycle of a Recycled Plastic Bottle? (resources.pepsicorecyclerally.com/resources/what-is-the-life-of-a-plastic-bottle/)
WWF - The Lifecycles of Plastics (wwf.org.au/blogs/the-lifecycle-of-plastics/)

Encourage students to research and gather as much information as possible on the steps required to make plastic bottles before creating their flow charts. Their charts should also include as much information as possible about where water is used in both of the production processes.

Once they begin drawing their charts, explain that their drawings don’t need to be perfect and they may need to conduct and incorporate further research around the different stages. This may mean they need to amend their drawings by crossing out and adding new information. This does not mean they need to start again; instead, their drawings can be used as a working document.

Learning extension: Students requiring extension could imagine that the bottles they are analysing will be filled with water; where does this water come from and what are the resource costs associated with extracting and transporting this water? This information could be included as a separate flow chart.

Step 3

Once complete, invite groups to share their flow charts with the class, ensuring that everyone has a good understanding of the differences between the two processes, especially regarding water usage.

Use the following examples to clarify any student misunderstandings about the flow charts they created:

New:

Recycled:

Give groups a chance to amend their drawings based on the information shared as a class.

Step 4

Engage students in a brief class discussion around the results of their research and remind them of the questions that were posed earlier in the lesson:

Why do you think making a single-use plastic bottle takes so much water?
Do you think it would be much different for a bottle made of our recycled materials? Why or why not?

Have students managed to find the answers to these questions? How did their guesses (check with the scribe!) compare to the answers they have now?

Take Action: Reducing water in plastic production

Step 1

Explain that as consumers become more aware of plastic's environmental costs, many companies that make plastic are seeking to create their products in ways that use fewer resources and minimise environmental harm. Scientists can be engaged to think creatively about how science can help with this challenge. For example, scientists have helped to develop bioplastics - a type of plastic made from renewable materials like corn, algae or fish scales. This is a solution that helps to solve the problem of plastic waste. But what about the process of making plastic? How could science be used to reduce the environmental impact of the plastic production process? How could science help us create production processes that use less water?

Students will now think about how the production of plastic bottles could be improved in terms of water usage. They can choose to focus on either virgin production (using new resources) or recycled production (using recycled plastic) and should aim to identify the sections of either production process where water usage could be reduced.

In the places where students identify water usage could be reduced, they should try to design an alternate method for this step of production that aims to use less water. The aim here is to think critically and creatively about reducing water usage and to use scientific reasoning to justify their ideas.

For example, students may focus on the step where recycled plastic flakes are washed to remove contaminants. Students could suggest that recycled sewage water be used for this process and that water that has already been used could be filtered and recycled. Alternatively, plastic flakes could be placed into barrels with loose sand and shaken; the aim here could be that the contaminants could removed by sand abrasion.

Step 2

Students could work in pairs or small groups to brainstorm ideas for reducing water usage, selecting to focus on either virgin or recycled production. These ideas could be recorded on new sheets of butcher’s paper.

Students could begin their brainstorming based on some of the suggestions in the Water Reduction Ideas Fact Sheet.

Step 3

Students can then work independently to select the ideas for water usage they think will result in the greatest water savings. Each student should then create a new chart for the production process they are focusing on (virgin or recycled) that shows the new stages for production they have come up with. This final chart can be based on the ones they made earlier on the butcher's paper but should be considered as a final, neat design. It could created using a desktop or online tool (e.g. Canva) and should include graphics and annotations to explain the new stages and how they reduce water usage.

You could provide students with the Chart Assessment Rubric to support them in creating their charts.

Learning extension: Students requiring extension could include additional steps to their flow charts that show bottles being filled with water, transported and sold in shops, consumed and then disposed of. Students could include annotations that describe the resource costs associated with these steps.

Step 4

Provide students with an opportunity to share their designs (e.g. peer to peer), and consider providing time for students to incorporate feedback before submitting their work for assessment. You could use the Chart Assessment Rubric to guide your assessment.

Reflection

Invite students to respond to the following question (also available on the Student Worksheet):

Why should we be investigating and refining recycling production processes?

Visy Education - Water Consumption in Production

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Summary

Lesson Guides and Printables

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Visy Education - Water Consumption in Production

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Summary

Lesson Guides and Printables

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