Goals for the session

Children aged 7 to 12 should learn to collect and record data carefully, recognise common materials such as paper, plastic, metal, glass and food waste, and use evidence to suggest a practical change. The aim is informed action, not worry about the planet.

Children take away a bar chart built from their own data, a clearer idea of which bin each item belongs in and one change they have agreed to try. Keeping the chart on display until the repeat audit gives them a reason to check whether their idea is working and to talk about it with other classes.

Sample session: classroom waste audit (70 minutes)

For 12 to 20 children in groups of four. The adult collects one or two days of general and recycling waste from a classroom, excluding tissues, sharp items and anything from toilets or kitchens. Materials: disposable gloves for everyone, a large sheet of plastic on the floor, labelled boxes for each material, kitchen scales, a tally chart and a bar chart template.

• 0-10 min: Explain the purpose and the safety rules. Everyone puts on gloves.

• 10-35 min: Groups sort the waste into the labelled boxes. Anything that does not fit goes in a 'not sure' box for discussion.

• 35-45 min: Weigh each box and record the results.

• 45-55 min: Build a bar chart on the board. Which material is largest? What went in the wrong bin?

• 55-70 min: Each group proposes one change, for example a paper scrap tray for reuse, and agrees how to measure whether it works.

Safety notes

The adult checks the bags before the session and removes anything sharp, soiled or unknown. Children wear gloves throughout and do not touch their faces during sorting. Wash hands thoroughly at the end, and wipe tables with an antibacterial cleaner. If waste cannot be checked safely, use clean packaging collected over a week instead.

Adapting for different ages

Younger children can sort clean packaging into three boxes, paper, plastic and other, and count items instead of weighing. Older children can calculate percentages, repeat the audit two weeks later to measure the effect of their change and present the results to another class or the school council. A follow-up session could compare how long different materials last outdoors by burying samples in labelled plant pots.

Key points

• Use the children's own waste so the data feels real.

• Check every bag yourself before children handle it.

• Turn results into one small, measurable change.

• Repeat the audit to show whether the change worked.

Ready-made resources

Printable session plans and materials for this topic are available from EduTrend Contents: W4C-120 Young Scientists Lab.

Photos: Salah Darwish, Sandie Clarke / Unsplash