Teaching Sequence

20 minutes – Part A: Where does my deodorant can come from?
15 minutes – Part B: Can I recycle my deodorant can?
20 minutes – Part C: Compare the differences.
15 minutes – Reflection: What can my deodorant can be remade into?

Work through this resource material in the following sequence:

Part A: Where does my deodorant can come from?

Step 1.

Begin this lesson by reading out (or writing on the board) the Thought Starter: “Deodorant cans – where do they come from and where do they go?”. Invite students to think about where their deodorant can came from originally, and record their ideas on the Student Worksheet.

Step 2.

Now show your class this Raw Materials Chart and ask them to state the metals used to create deodorant cans and what raw materials these metals have come from, and then record their responses on the Student Worksheet.

To get students thinking more deeply about the topic, ask your class questions similar to the following:

Where does steel/aluminium come from?
Where is iron ore/bauxite found?
How are these materials turned into metals?
How much time and energy does it take?
What is the effect of extracting and processing these materials on the environment?

Step 3.

Now distribute the Aluminium Factsheet and ask your class to read through the following two sections: “How is aluminium made?” and “What is the energy cost?". Alternatively, read through these sections as a class.

As students are reading, ask them to identify four directly proportional relationships and then calculate the constant of proportionality for each using Table 1 of the Student Worksheet. Encourage students to put the ‘output’ value as y and the ‘input’ value as x (e.g. bauxite is refined to produce alumina, so bauxite is the input value, x, and alumina is the output value, y.) If your class is less familiar with direct proportion or requires scaffolding, complete the first row of the table as a class and allow students to try the remaining rows on their own.

Solutions
Directly proportional relationship y ∝ x	Proportionality constant Using y = k x
Tonnes of alumina produced ∝ tonnes of bauxite refined	y = k x y = 1 tonne of alumina, x = 2 tonnes of bauxite 1 = k*2 1 / 2 = k k = 0.5 Direct proportion formula: y = 0.5x
Tonnes of aluminium produced ∝ tonnes of alumina smelted	y = k x y = 1 tonne of aluminium, x = 2 tonnes of alumina 1 = k*2 1 / 2 = k k = 0.5 Direct proportion formula: y = 0.5x
Tonnes of CO₂ produced from refining ∝ tonnes of alumina produced	y = k x y = 1 tonne of CO₂, x = 1 tonnes of alumina 1 = k*1 1 / 1 = k k = 1 Direct proportion formula: y = 1x
Tonnes of CO₂ produced from smelting ∝ tonnes of aluminium produced	y = k x y = 15.6 tonnes of CO₂, x = 1 tonnes of aluminium 15.6 = k*1 15.6 / 1 = k k = 15.6 Direct proportion formula: y = 15.6x

Discuss with students the amount of carbon emissions released from the production of aluminium as described in the factsheet. Also ask students to think about what other processes might be involved in the production of aluminium (besides refining and smelting), which raise the carbon emissions even higher. Use the following points to prompt further discussion:

Mining costs (e.g. running machinery)
Transport (bauxite to refineries, alumina to smelters, aluminium to manufacturers)
Production of aluminium into sheets.

Part B: Can I recycle my deodorant can?

Step 1.

Now that students have looked at the amount of energy required to produce deodorant cans from bauxite, encourage them to start thinking about recycling. Invite them to respond to the following:

Are deodorant cans recyclable? (Ask for a show of hands if students think yes or no)
Do you recycle your deodorant cans or other aerosol cans? (Ask for a show of hands for yes and no)
Why do you think people don’t recycle their deodorant cans?

Step 2.

Now ask students to read the remaining information on the Aluminium Factsheet and to look out for more directly proportional relationships. This time, tell students look for two relationships concerning the recycling of one tonne of aluminium (as the input value) and to record their responses on Table 2 of the Student Worksheet.

Solutions
Directly proportional relationship y ∝ x	Proportionality constant Using y = k x
The saving of 4 tonnes of bauxite ∝ recycling one tonne of aluminium	y = k x y = 4 tonnes of bauxite, x = 1 tonne of recycled aluminium 4 = k*1 4 / 1 = k k = 4 Direct proportion formula: y = 4x
The saving of 9 tonnes of CO₂ ∝ recycling one tonne of aluminium	y = k x y= 9 tonnes of CO₂, x = 1 tonne of recycled aluminium 9 = k*1 9 / 1 = k k = 9 Direct proportion formula: y = 9x

Discuss with students how recycling aluminium will help the environment. Ask them to discuss their ideas with the class or a peer, and describe a few ideas using the Student Worksheet. If they need a prompt, encourage students to focus on the CO₂ emissions they read about on the fact sheet.

Part C: Compare the differences

Note: In this section, students will use their direct proportion formulas from Part A and Part B to calculate yearly costs regarding Australia’s use of deodorant cans.

Step 1.

Explain to students that they will now be investigating the differences if their deodorant cans were produced from raw bauxite, or recycled aluminium. Start by asking students to find the number of deodorant cans purchased by Australians each year from their factsheet.

Step 2.

Now explain to the class that we are going to assume that all 250 million cans are produced from aluminium even though some of these are produced from steel. This will overestimate figures somewhat, but since the mining and production of steel also require very large amounts of energy and steel is also 100% recyclable, these projections are not unreasonable.

Weigh the deodorant can/s or ask student volunteers to complete this task for you. If you are using a full deodorant can, you should be able to deduct the weight of the product (as stated on the label) to be left with an approximate weight for the can (e.g. A full can weighs 210g with 150g of product, so the can is approximately 60g). If you are using multiple deodorant cans then average their weights for a better approximation. If you are unable to weigh deodorant cans, use 60g as an approximate weight.

Step 3.

Next, explain to students that we have calculated the weight of aluminium for these deodorant cans, but now need to calculate how much alumina and bauxite would have been used to produce this. Ask students to use their direct proportion formulas and work backwards to find these values. Students can just use relevant multipliers (e.g. x2 for alumina, x4 for bauxite) but should be encouraged to use their formulas so they may practice their rearranging and solving skills. Students can use Table 3 of the Student Worksheet to record their ideas.

Alumina to aluminium formula:
y = 0.5 x (from Part A)
15,000 = 0.5 x
15,000 / 0.5 = x
x = 30,000
Approximately 30,000 tonnes of alumina

Bauxite to alumina formula:
y = 0.5 x (from Part A)
30,000 = 0.5 x
30,000 / 0.5 = x
x = 60,000
Approximately 60,000 tonnes of bauxite

Step 4.

Now students will calculate the environmental costs in terms of amount of bauxite and CO₂ when aluminium is produced from raw materials or recycled materials. Students will need to use several formulas from Part A and B to calculate these figures. Ensure that students are taking care to input the correct ‘x’ value for each formula (e.g. bauxite, alumina or aluminium figure). Students can use Table 4 of the Student Worksheet to record their answers.

Bauxite

Amount used in tonnes (Raw)

Amount saved by recycling in tonnes

% Saved by recycling

Bauxite (Refining)

60,000 (calculated in step 3)

Formula: y = 4x
(from Part B)
Working
y = 4 x 15,000
y = 60,000

60,000 / 60,000 x 100

= 100%

Ensure students understand that they only need to calculate the total value for the recycling column in this table and compare this with the total (refining + smelting) in the raw column. Students can use Table 5 of the Student Worksheet to record their answers.

CO₂e emissions	Amount emitted in tonnes (Raw)	Amount saved by recycling in tonnes	% Saved by recycling
Refining	Formula: y = 1x (from Part A) Working y = 1 x 30,000 y = 30,000	Formula: y = 9x (from Part B) Working y = 9 x 15,000 y = 135,000	135,000 / 264,000 = 51.14 %
Smelting	Formula: y = 15.6x (from Part A) Working y = 15.6 x 15,000 y = 234,000
Total (refining + smelting)	30,000 + 234,000 = 264,000

Step 5.

Now, to ensure students have understood the significance of this task, ask them to describe their findings in words. Encourage your class to “explain how the environmental costs would differ (per year) if Australia’s deodorant cans were produced from raw or recycled materials”. Students should be using their calculations in their response.

Reflection

Step 1.

Discuss with students the main environmental benefits for recycling aluminium: to conserve bauxite and reduce carbon emissions. Ask students if they can think of any other benefits for recycling aluminium. Encourage students to discuss their thoughts and list a few ideas. Prompt students on the following, if needed:

Diverts waste from landfill.
Aluminium is not biodegradable so recycling is the best option.
Bauxite is non-renewable but aluminium can be reused over and over since it does not lose value upon being recycled.
Protecting environments and ecosystems (since bauxite will not need to be mined).

Step 2.

Now that students have a good understanding of the differences in production costs when aluminium is produced from raw or recycled materials, encourage your class to think about what their deodorant cans might be turned into. Direct students to the video below, which shows a real factory producing beverage cans from aluminium. You could also provide students with this Aluminium Recycling Process - Diagram to supplement their understanding of how cans are made, or in place of the video. As students are watching the video, ask them to answer the following questions (also available on the Student Worksheet):

How many cans are able to be produced in a day?
How does the aluminium first arrive in the factory, for manufacturing into cans?
What sustainable practices are utilised in the production of these cans?

Answers below:

1.5 million cans are produced each day.
Aluminium sheet rolls (which is what aluminium is generally made into before being manufactured into other products).
Recycling of all scrap material or faulty products, to be reused.

Visy Beverage Can Facility at Yatala (https://vimeo.com/207544742)

Step 3.

Now ask your class to calculate the weight of cans that can be produced in a single day. They will need to use 14.9 grams as the average weight for a beverage can (Source: https://recycleusainc.com/category/aluminium-cans/).

Once students have calculated their answer, ask them to imagine the production ability of this one factory over the course of the year. Prompt their thinking with the following questions:

If they can produce 1.5 million cans a day, how many in a week? Or a year?
And if this is just one factory, how many other factories are producing cans as well? In Australia? In the world?
How much aluminium is this?
How many carbon emissions would this add up to?
And where is all of this aluminium going? Is it recycled? Or sent to landfill?

Once students have grasped some concept of the amount of aluminium being used around the world, ask them to explain why the recycling of aluminium is so important.

Step 4.

Explain to students that many people in Australia believe that aerosol cans can't be recycled (source). Ask students to consider reasons as to why aluminium (particularly deodorant cans) are being thrown away. In response to this, direct students to ‘send a message’ to average Australians about the production and recycling of aluminium. Encourage students to use the given space to draw a picture, create a poster or to share statistics regarding aluminium usage. They may also wish to use other media or electronic devices to complete this task.

Differentiated Learning

Extension – This lesson could be extended by reducing the amount of scaffolding and teacher direction. High ability students or extension classes may not need as much teacher guidance and may enjoy completing the lesson at their own pace. This activity could also be extended by investigating and researching additional carbon emissions in the production of aluminium (including mining and transport). As part of the final reflection task, students may also be encouraged to write a more detailed report of the issue which outlines the main points of the investigation and aims to justify why all aluminium needs to be recycled.

Provisions for Learning Support – Depending on support requirements, students requiring learning support could work in a pair or group or receive additional scaffolding. The lesson could also be shortened by investigating carbon emissions only (not bauxite) and by providing some of the proportionality formulas.

Teacher Reflection

Take this opportunity to reflect on your own teaching:

What did you learn about your teaching today?
What worked well?
What didn't work so well?
What would you share?
Where to next?
How are you going to get there?

The information and statistics included in this document are approximate and have been simplified for educational/illustrative purposes. They should not be relied upon for any other purpose.

Visy Education - Aerosol Assault

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