Teaching Sequence

10 minutes

Tune In: Where is energy stored?

10 minutes

Find Out: Where does green waste fit in the circular economy?

30 minutes

Take Action: Green energy

10 minutes

Reflection

Tune In: Where is energy stored?

Step 1

Let’s build up a food web. Start by asking your students to name an animal. For the purpose of this exercise, it may be easier for students to choose a local animal that they are familiar with. Write this animal on the board. Ask your students, what does this animal consume? Write their suggestions below and draw arrows from their suggestions to the original animal. Explain that in a food web, these arrows show the flow of energy from one element to another. At this stage, your board may look like this:

Step 2

Next, ask students to think about what might consume this animal. Write these suggestions above your original animal. Ask students which way the arrows should point to show the energy flowing into the next trophic level. Now, your food web might look like this:

How high can this food web go? From your original animal, follow the food chain up until you hit a top predator.

Step 3

What consumes that top predator? While it has no natural predators, eventually it will die and be consumed by scavengers and decomposers. From here, we can make a closed loop like so:

So long as all of the components stay in the food chain, it creates a nearly lossless system for energy recapture. This could be called a Circular Economy. Let’s take a closer look.

Find Out: Where does green waste fit in the circular economy?

Step 1

Watch this video with your students:

Today, we’re going to focus on the biological cycle and how we can apply this to our situation here at school. What resources and materials can we recapture from our waste stream here at school? And why should we be recapturing these? Watch this video with your students to start answering these questions:

Step 2

Ask your students: What biodegradable waste does our school produce? They may suggest:

food scraps
garden waste (grass clippings, leaves, sticks and branches etc.)
wastewater
sewerage.

Once you have several suggestions, explain that they will be investigating one of these waste streams and proposing a method that their school could use to recapture this energy.

Take Action: Green energy

Step 1

This is where your students take the lead! Either individually or in small groups, they need to select one of these green waste streams and investigate strategies to better recapture this energy in their school. Using the student worksheet as a guide, they will need to investigate:

different methods and technologies for managing this waste stream
the ecosystem diagram depicting what is happening in their chosen method
biotic and abiotic factors that will impact their method
and what benefits this method will provide to the school.

Let students know:

the time allocation they have for their research
the resources they have available to conduct their research
and the roles of different group members (if working in groups)

Step 2

Divide your students into appropriate groups to work on their projects. You can either assign green waste streams to your students or let them choose from your list.

Learning support: There is the option to focus on a specific type of green waste. For example, rather than investigating all garden waste (e.g. leaves, grass, weeds, branches, trimmings, etc.), students could focus just on a specific type (e.g. grass clippings). This reduces the number of factors they need to consider.

Provide students with the time to work on their research projects and to complete steps 1 to 6 on their student worksheets.

Literacy extension: To extend this research project, you could ask students to complete an elevator pitch for their chosen method.

Numeracy extension: Students could expand their research to investigate, firstly, the quantities of this green waste stream the school produces and, secondly, the costs involved in setting up and maintaining this green waste system. This data could be used as part of their elevator pitch to support their case for the school adopting this method.

Reflection

Ask your students to complete the reflection on their student worksheet. They will need to answer these questions:

What benefits would this method provide to your school?
Is this method an improvement on your school’s current method? Why/why not?
Would this method be suitable for your school? Why/why not? If your answer is no, what would need to change for this method to be suitable?

Creating a Green Circular Economy

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Creating a Green Circular Economy

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