What it shows
Household waste belongs in different bins: wet kitchen waste for composting, dry recyclables, hazardous items like batteries and medicines, and sanitary waste. Sorting cards into four coloured bins teaches the habit and shows how little should really go to a landfill.
The science
Wet waste such as peels rots into compost, so it must not be mixed with plastic. Dry waste such as paper, plastic bottles and metal can be recycled only if it is clean and separate. Batteries, bulbs and expired medicines contain substances that poison soil and water, so they go to a special collection. When waste is mixed, almost all of it ends up in a dump that leaks and smells, so sorting at home is the first and cheapest step in managing waste.
Materials
Cost: under Rs 50. Many items come from home or from waste; spare parts such as LEDs, motors and wire are in the store.
- Four small boxes painted green, blue, red and yellow
- Forty cards with drawings or cut-out pictures of waste items
- A chart paper for the answer key
- Colours and glue
- A timer
Safety
This project uses safe, everyday materials. Still, read the rules below with a parent before you start.
Never use mains electricity: power models with cells, batteries or a low-voltage adapter. Sharp and hot tools, flames and lab chemicals need an adult or your teacher beside you. Keep magnets, button cells and small parts away from young children, and wash your hands after making.
All the safety rulesStep by step
8 steps. Do them in order, and test each part before you go on to the next. Write what you notice in a notebook as you go.
Paint or cover the four boxes: green for wet, blue for dry, red for hazardous and yellow for sanitary waste.
Draw or paste pictures of 40 items on cards: peels, bottles, a battery, a bandage, newspaper, a bulb, tea leaves, a pen, and so on.
Write the correct bin colour on the back of each card as the answer.
Make a chart listing ten examples under each colour.
Play: shuffle the cards and sort all 40 into the boxes in two minutes.
Check the backs and count the correct ones; the score is out of 40.
Count how many cards went in each bin and note that the red and yellow bins have the fewest.
Ask three family members to play and record their scores on the chart.
What you should see
A working game where most players score above 30 after one round of explanation, and a chart showing which items people most often put in the wrong bin.
Viva questions
A teacher or a judge will ask how it works. Try to answer each question before you open it, then compare.
1Which bin does a banana peel go in?
The green wet waste bin, for composting.
2Why keep batteries separate?
They contain metals that poison soil and water.
3Can a dirty pizza box be recycled?
No; the oil spoils the paper, so it goes with wet waste or is cleaned first.
4Why is sorting at home important?
Mixed waste cannot be composted or recycled and ends up in a dump.
Take it further
Add a fifth e-waste box and find out where in your town old phones and chargers are collected.
Change one thing, measure what happens, and add a table or chart of your readings: that is what turns a model into your own investigation.
Free ebooks for this project
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