What is in soil?
Soil looks like plain brown dirt, but it is full of surprises: tiny bits of rock, old leaves, water, air and lots of living things. Let's take a close look at a handful!
Read
Soil is the loose layer on top of the ground. Plants grow in it.[2]
Soil is made of tiny bits of broken rock, bits of old dead plants and animals, water and air.[1][2]
Soil is full of life! A spoonful of healthy soil has more tiny living things in it than there are people on the whole Earth.[7]
Earthworms eat old, rotting leaves. Some worms pull leaves down into their tunnels. Worms help to keep soil healthy.[6]
Fungi and tiny living things break down dead leaves and turn them back into soil food for plants.[7][2]
Soil grows very, very slowly. A thin layer, as thick as your little finger is wide, can take hundreds or even a thousand years to make. So we must look after it![3][1]
Almost all the food we eat grows in soil, or comes from animals that eat plants grown in soil.[3]
Try it: Soil detectives
You need
- A cup of garden soil (from a place without dog or cat mess)
- A white paper plate or sheet of paper
- A magnifying glass
- A lolly stick or plastic spoon
- A clear cup of water
- Gloves (optional)
Safety
Use soil from a clean place, never where pets go to the toilet. Do not eat soil or put your fingers in your mouth. Wash hands with soap afterwards. Be gentle with tiny animals and put them back outside.
What to do
- Spread the soil thinly on the white plate.
- Look with the magnifying glass. Use the stick to push things apart.
- Sort what you find: little stones, bits of leaves or roots, and any tiny animals.
- If you find a tiny animal, look, then put it gently back outside.
- Drop a lump of dry soil into the cup of water and watch closely. Do you see bubbles?
- Wash your hands well.
What happens, and why?
Soil is a mix of rock bits, old plant pieces, water and air. The bubbles you see come from the air that fills the tiny gaps between the bits of soil: about a quarter of a typical soil is air. When water fills the gaps, the air bubbles out.[1]
Play: Living or not living?
Here are things you can find in soil. Is it alive, or not alive? Tap the right box.
Your best score is kept only on this device. Nothing is sent anywhere.
Quiz
Other ages: Ages 10–11 · Ages 15–16