Teacher Preparation

Overarching learning goal: By participating in this activity students will understand the environmental problems associated with sending green waste to landfill and will recognise the benefits of recycling green waste and composting. Students will also understand how to design and conduct a survey of the school community.

Teacher content information: Many people think that sending green waste to landfill is fine. It’s natural right?? Surely it just breaks down and creates good soil that helps the environment?? No, sadly, this is not what happens at all.

Landfill sites are essentially great big piles of rubbish. There is no air in these great big piles and this means nothing much breaks down in them at all (did you know that old landfills are now being treated as archaeological sites because the waste is so well preserved?!). The only organisms that can survive in a landfill are bacteria which decomposes the waste anaerobically (without using oxygen). Unfortunately when they go to work to break down organic material like green waste and food they create methane, a greenhouse gas that’s 20 times more potent than carbon dioxide. The average Australian household produces about 700kg of greenhouse gas emissions from food and garden waste each year, about half from each.

Organic waste decomposing anaerobically in landfill also produces leachate, a liquid that’s created as waste materials decompose. Leachate is made up of decomposed materials plus rain, when it falls on the landfill site. Because this leachate contains substances harmful to the soil, groundwater and waterways it must be carefully managed to ensure it is contained.

If green waste is put in your green waste bin, it is sent in a truck to a facility where it is composted. Composting is a natural process of decomposition using oxygen (aerobically) that is better for the environment. The little decomposition critters that can survive in a composting system don’t produce methane like the bacteria in landfill. Furthermore, composting turns green waste into a range of high quality, natural soil conditioning products such as mulches, composts, blended soils and potting mixes used in landscaping, horticulture and agriculture. These products take green waste back to earth, enriching the soil and helping to grow healthy crops and pastures that produce food for everyone. Today’s green waste can grow tomorrow’s lunch! You’ll never look at your lawn clippings in the same way again…

The data collected through the survey could be used in the Considering Social Action - Back to Earth Communication Project. How you want to use the data might influence the types of questions your students want to ask and how you want to record this information. For example, if you want to make a short documentary, you will need to record participant answers with a video camera.

Student and classroom organisation

Teaching sequence

20 minutes – Introduction, reviewing waste words and definitions and reading through Back to Earth website.
40 minutes – Designing survey.
60 minutes – Conducting survey.
50 minutes – Analysing and presenting data.
10 minutes – Reflection questions.

Step 1.

Begin by reviewing the following words and definitions with students by asking students to match the correct word with the definitions on the Student Worksheet:

Waste - Any material that is discharged, emitted or deposited in our environment in a way that causes a problem for our environment.
Organic waste - Any animal or plant based material and degradable carbon such as garden organics, food, timber, paper and cardboard.
Green waste - Biodegradable waste that can be composed of garden or park waste, such as grass or flower cuttings and hedge trimmings.
Food waste - Food that is discarded or cannot be used.
Compost - Decomposed organic material used as plant food.
Landfill - The disposal of waste into or onto land.

Once complete, ask students to share their answers and make corrections where necessary.

Step 2.

Ask students to read the following two pages from the Back to Earth website (also available on the Student Worksheet):

Students should then respond to the associated questions on the Student Worksheet.

Step 3.

Explain to students that they will be conducting a survey of the students, parents and staff at their school to find out:

How many people have a green waste bin at home;
How many people regularly use the green waste bins at home;
What they can put into them and what they shouldn’t;
Why they do or don’t use them; and
What information people need to use their green waste bins more often or more correctly.

Students should use the Survey design tips factsheet to help them design their survey questions. Students can work as a class to design the survey, or students can work in groups of 4 or 5 to design their own surveys. They should use the facts and information on the Back to Earth website to guide their survey.

NOTE: Although this Factsheet is designed to help students create their surveys, it is recommended that teachers provide more guidelines for creating the surveys. For example, depending on student age or ability the teacher may want to:

Limit the number of questions included in the survey;
Prescribe the type of questions asked (e.g. YES/NO answers or open-ended – this might depend on what students want to do with the data – see the Considering Social Action for ideas on using the data collected in the survey to form the basis of a communication project);
Clarify how students will conduct the survey (e.g. answers written by interviewers or interviewees, recorded on camera or phone, completed in private);
Remind students to thank participants and to protect participants who wish to remain anonymous.

Step 4.

Conduct your survey! If students work in groups to conduct their surveys, assign different groups with different participants to survey, for example, different year levels, staff or parents so that they are not surveying the same people more than once.

Assessment

Bring your data back to the classroom. How will your students analyse and present this data? For example:

Create a poster or infographic displaying responses
Create a graph or table showing numbers and percentages
Conduct small group discussions
Plan some further actions.

Reflection

Ask students to complete the Reflection Questions on the Student Worksheet.

Differentiated Learning

Extension:

Ask students to create three different types of graphs to represent the data.
Contact the waste officer at your local council or waste recovery facility to organise a site visit/tour.

Provisional Learning Support: Ensure students with learning difficulties are teamed with more capable students.

Homework

Ask students to research other types of organic processing technologies and to prepare a short report describing one of these technologies.

Back to Earth - Green Waste Survey

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