How to Teach Kids About Recycling and Waste With Simple Experiments

Children are often told to recycle without being shown why. Simple experiments make waste visible and give them real evidence to think about. You do not need to preach. Let them measure, observe and draw their own conclusions.

Because this involves rubbish, a few hygiene rules apply: wear gloves for handling, avoid food waste that smells strongly, never touch broken glass, sharp tins or anything that held chemicals, and wash hands afterwards. Adults should handle anything risky.

Experiment 1: weigh the week

For one week, collect the household’s clean recyclable items and the general rubbish in separate bags or boxes. At the end, weigh each with kitchen scales (grams or kilograms; pounds work too). Ask:

Which pile is heavier?
Which takes up more space?
What is in the rubbish that could have gone somewhere else?

Record the numbers in a notebook. Try again a month later after making one change, and compare. This is a before-and-after test, and it needs no judgement about what you did well.

Experiment 2: what rots and what doesn’t

Bury small items in a container of soil or leave them in a damp, covered tray: a piece of apple core, a scrap of paper, a leaf, a bit of cotton cloth, a plastic wrapper. Label each one. Keep the container somewhere outdoors or a spot where it can stay for a few weeks, and take a photo every few days.

Ask your child to predict which will change most. After a few weeks, dig carefully and compare. They will see that some materials break down quickly and others hardly change. Wash hands afterwards and dispose of the container contents sensibly.

Experiment 3: sort by material

Spread clean items on a mat and sort them by what they are made of: paper, card, metal, plastic, glass. Then try sorting by property: does it float, bend, tear, let light through? Use a magnet to find which metal items are attracted (steel) and which are not (aluminium). This shows why sorting at a recycling facility is possible.

Experiment 4: can you reuse it?

Challenge your child to find a second use for five items before they go in the bin. A jar becomes a pencil pot. A tube becomes a ramp. A cardboard box becomes a sorting tray. The goal is not perfect solutions but the habit of asking “What else could this be?”

Experiment 5: how much paper can we save?

For a week, keep a pile of paper that has only been used on one side. Count the sheets. Next week, use both sides, and count again. Compare. Small numbers still make a clear point.

Talk about the bigger picture

Keep the conversation honest and age-appropriate. Younger children can learn “reduce, reuse, recycle” in that order: using less comes first. Older children can ask where waste goes in your area, since systems vary a great deal between places. A local council or municipal website is a good place to look.

Avoid frightening claims. It is enough to say that materials have a journey and that we have choices along the way.

What counts as evidence

Remind your child that experiments help us notice and decide. If a test does not turn out as predicted, that is useful. Ask what might have affected the result, such as the weather, the size of the item or how long you waited.

Keep it practical and calm

Children can feel anxious when they hear about waste and pollution. Focus on things they can do and measure: a smaller bin, a reused jar, a bag of paper saved. Let them notice that small changes show up in the numbers. If they raise bigger worries, listen, tell the truth in simple terms and remind them that many people are working on these problems, and that curiosity and careful thinking are useful tools.

Where to go next

For a ready-made lesson, try What’s in our garbage? or see the full Earth Day unit. Our post on the garbage audit works at home too, and recycled materials experiments give you more ideas.