Earth and Environmental Science 11–12 · Year 12
Composition of household or school waste: a sorted and weighed audit (syllabus practical)
Module 8: Resource Management
School laboratory, not for home
In a school laboratory, with a teacher supervising, under the school's risk assessment. Not for home.
The idea
What goes in the bin is measurable, and the mass fractions of food, paper, plastic, glass and metal decide which management options save the most resources.
Safety card
Setting: In a school laboratory, with a teacher supervising, under the school's risk assessment. Not for home.
Hazards
- sharps and broken glass
- mould and food-borne bacteria
- sanitary or medical waste must not be sorted
Controls
- gloves and tongs
- exclude bathroom bins
- wash hands
- sort outdoors on a tarpaulin
Note
No hazardous chemicals or heat sources: record the activity in the school's RiskAssess risk assessment, following the NSW Department of Education Science safety and compliance page; the Chemical Safety in Schools package is not triggered.
What you need
- one day’s waste from a set of classrooms or a household, bagged and dated; a tarpaulin, sorting tubs labelled food, paper and card, soft plastic, hard plastic, glass, metal, other
- gloves, tongs, balance to 10 g, hand sanitiser
- Sustainable Schools NSW waste resources for category definitions
How to do it
- Weigh the whole bag, then sort every item into the tubs and weigh each tub.
- Calculate the mass fraction of each category and its share of the total; check that fractions sum to 100 %.
- Record which fractions would go to landfill, recycling and organics under the local council’s bins.
- Repeat on a second day and report the mean and range.
- Evaluate one option (composting, recycling, avoidance) against the syllabus criteria: energy, environmental impact, space, facilities and demand.
What you should see
Fractions summing to 100 % with the largest category identified; for example a tub of 3.2 kg from an 8.0 kg bag is 40 %. The learner names the largest category by mass and the share that could leave the landfill stream under the council’s existing bins.
What changes
This activity lists no variables to change, measure and keep the same.
Common misconceptions
Each of these ideas is wrong, and the activity is a chance to test it.
- Recycling everything solves waste (avoidance comes first).
- Plastic is the heaviest part of the bin.
Curriculum references
The NSW syllabus outcomes and Australian Curriculum v9 codes this activity supports. They are references, not a verified or complete curriculum alignment.
- Earth and Environmental Science Stage 6 Syllabus (2017), NESA; current, replaced by the 11–12 Syllabus (2025) from 2028EES12-15EES11/12-5EES11/12-6EES11/12-7
- Earth and Environmental Science 11–12 Syllabus (2025), NESA; to be implemented from 2028, not yet taughtEES-12-04
- Australian Curriculum v9No Australian Curriculum v9 code is listed.
Sources
The pages the author read to write this activity.