Teaching sequence

Work through this resource material in the following sequence:

15 minutes

Tune In: Changing containers

25 minutes

Find Out: The weight of change

15 minutes

Take Action: Adding to change

5 minutes

Reflection

Tune In: Which containers?

Step 1

At the front of the classroom, display an example of each of the following containers:

aluminum can
glass bottle
PET bottle
liquid paper board container
HDPE bottle
steel beverage can (e.g. coconut water can).

Invite students to make observations about the containers. What is different about them? What do they all have in common? After the students have discussed their observations, ask if they knew that for each of these containers, they could get 10¢. Let’s look at this further.

Step 2

Show the videos WA | Scheme Overview (Captions) and CFC Glass - CHILD FRIENDLY and then discuss how the Containers for Change scheme operates. After explaining the program, show the poster Reinventing your 10c Containers referring back to how all containers shown at the front of the room can be recycled through the initiative, earning you money as you return them.

Invite students to consider the following questions using the Think-Pair-Share approach:

What are the environmental benefits of this scheme?
What are the benefits for individuals who collect and return the containers?
What is the benefit for businesses?

Step 3

Together we are going to explore the impact of the Containers for Change initiative by figuring out just how much material has been recycled.

Show Image 1 ‘Total Weight of Material Types Processed by Refund Point Operators & Material Recovery Facilities’

Invite students to discuss the following questions;

What information is this image giving us?
How much is a tonne?
What does this tell us about the amount of each different type of material being recycled?

Using the Turn and Talk approach, invite students to make predictions about how many individual containers would have been recycled to make each weight shown. Explain to them that this is a prediction, and they will do further mathematical investigations later in the lesson. Provide them with the student worksheet and prompt them to record their predictions in the first section.

Step 4

Explain to students that they will now investigate how many of a particular sized container would need to be recycled to form the quantity received in the processing plants. The class will investigate the first material, aluminium, together, and then students can work individually to solve for the other materials.

Model the process with the whole class using the aluminium can:

Show the table ‘Quantity of Aluminium cans’ on the interactive board or TV for all students to see (alternatively, you can print a copy or draw it on the whiteboard). Ask students how they would work out how many individual aluminium cans would make the total quantity recycled.

They will need to know the total weight received by the processing centre and the weight of an individual can. Referring back to Image 1, ‘Total Weight of Material Types Processed by Refund Point Operators & Material Recovery Facilities’, record the total weight of aluminium processed, which is 4,410 tonnes.

Let students know that for the purposes of this exercise, we will measure one container and take that to be the average weight for a container of that type. Invite a student to come to the front and weigh one of the 375ml aluminium cans. Record the weight in the column ‘Weight of one container’. At this point, you will have recorded the total weight recycled in tonnes and the weight of the individual container in grams. Remind students that the goal is to determine how many of the individual cans would equal the total weight received. Invite students to identify the obstacle to making this calculation and how it can be solved (i.e. the weights are not in the same unit of measure and will need to be converted).
Show students the ‘Converting Mass Units’ display to guide changing the total measurement (currently in tonnes) into grams. Explain that to change from Tonnes to kilograms, the amount will need to be multiplied by 1000. Invite all students to do this and then clarify the answer. Next, identify that it will need to be multiplied by 1000 again to convert to grams. Invite students to work this out again and then clarify the answer.

The calculations should reflect the following:
Aluminium processed = 4,410 tonnes
= 4,410,000 kilograms
= 4,410,000,000 grams

Note: If students are unfamiliar with strategies for multiplying and dividing by 10, 100 and 1000, you may wish to take some additional time here to focus on this specific skill, completing several examples together on the board before progressing.
Emphasise that the total weight of the aluminium recycled has now been converted to grams (four billion, four hundred and ten million grams) and that the measurement for the weight of an individual can is also in grams. Invite students to identify what process would need to be used to identify how many cans would need to be recycled to make the total amount processed.

Once identified, reinforce this for all students:
Total weight processed ÷ weight of the individual can = total number of cans required to make that weight

For example, 4,410,000,000 ÷ 14 (likely weight of the can) =

Invite students to use calculators to solve this equation using the weight you identified for the can.

Depending on the weight identified for your specific can, the answer will be somewhere around 2,974,714,286. Record this in the final column of the table displayed. Revisit what this information represents. The total amount recycled in WA from 2021 - 2022 was the equivalent of approximately the number of cans found. Prompt students to record all of the information shown in the first row of the table on their worksheet so that they have this first example for reference as they complete the remainder of the calculations.

Take this opportunity to discuss with students how larger numbers such as these are read accurately. The included resource, ‘Reading Very Large Numbers’, can be used for reference, if needed.

Find Out: The weight of change

Step 1

Invite students to complete the remaining sections of the ‘The Magnitude of Recycling’ worksheet, following the same process for each material.

Differentiated Learning - consider your students' knowledge and skills to determine if best for them to work in pairs, individually or in small groups. Students with more extensive mathematical knowledge may benefit from working independently and checking in with each other to clarify findings. Other students may benefit from working in mixed-ability pairs or it may be helpful to form a small group with less confident mathematicians to guide them through the process for a couple more materials before they begin to work independently.

Step 2

After allowing time for students to complete the investigation, reconvene the class and display a copy of the student worksheet ‘The Magnitude of Recycling’. Invite students to share their conversions and calculations about how many of each container would make up the total. Collate all the information into the class table.

When students may have different solutions, take time to discuss approaches and identify where a) errors were made or b) a variable impacted the outcome.

Step 3

Invite students to consider how many containers have been saved from landfill through recycling programs. Using the turn and talk approach, prompt students to discuss:

Where would these containers be without the Containers for Change program?
Where are the containers going because of the Containers for Change program?

Take Action: Adding to change

Step 1

Display the subsequent section of the worksheet under the sub-heading ‘Adding to Change’. Model completion of this section by:

circling what type of container you use the most
estimating how many you use in a week.
calculating how many that would be in one year.
calculating the weight that would be.
converting into the most suitable metric unit.

Once you have modelled these steps, consider how you could change your own habits to contribute to recycling and waste reduction and share your thoughts aloud with the class.

Step 2

Allow time for students to complete this section for themselves.

Opportunity for Differentiated Learning

Encourage students to support each other if some are unsure of the process of making these calculations. Encouraging more able students to support those who are unsure is of benefit to both students. Those who are unsure receive support, and the more confident students need to be able to consider and verbalise the process undertaken to someone else, requiring them to build awareness of their own mathematical thinking and processes.

Reflection

Invite students to continue on through the worksheet, responding to the following prompts:

Am I recycling as much as I can?
How can I recycle more?
Whose assistance will I need to do this?

Containers for Change WA - Container Loads

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Summary

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