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How Soil Is Made: Dig In with Digby the Mole

How Soil Is Made: Dig In with Digby the Mole

Learn how soil is made from tiny bits of rock and organic matter, then dig, break rocks, rot leaves and test soil in a jar with Digby the mole.

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What you'll learn

  • That soil is a mixture of tiny rock bits and organic matter
  • How rain, ice, plant roots and rivers break rock into smaller pieces
  • What organic matter is and which things can rot into it
  • How worms, woodlice and fungi help dead leaves rot into soil
  • Why dark topsoil holds more organic matter than the subsoil below
  • How to separate soil in a jar of water to see its layers

Chapter by chapter

  1. What is soil made of? Rock bits and organic matter Free to try

    Year 3 science · 1

  2. Rocks break into tiny bits to make soil

    Year 3 science · 1

  3. Organic matter: dead plants and animals rot into soil

    Year 3 science · 1

  4. Making soil: rock bits and organic matter mix over time

    Year 3 science · 1

  5. Soil in a jar: separating rock bits and organic matter

    Year 3 science · 1

  6. Soil detective challenge: what is soil made from? (8 questions)

What the chapters cover in the national curriculum in England:

  1. Year 3 science: Recognise that soils are made from rocks and organic matter

About this adventure

How Soil Is Made is an interactive science game that teaches children aged 7–9 how soil forms from tiny bits of rock and organic matter. It follows the Year 3 Rocks unit in the national curriculum for England.

Guided by Digby the mole, children break a boulder with rain, ice, plant roots and a river. Then they watch worms, woodlice and fungi rot fallen leaves into organic matter, the dark material made from things that were once alive. They see soil build up over hundreds of years and dig down through topsoil and subsoil. Finally they run a soil-in-a-jar test where heavy rock bits sink and organic matter floats.

Every step is spoken aloud with captions. A skippable warm-up revisits living, dead and never alive, and a final challenge checks what they remember.

Questions and answers

What is soil made of, in simple words?

Soil is a mixture of tiny bits of rock and organic matter, which is the rotted remains of plants and animals. It also has air and water hiding in the small gaps between its bits.

How do rocks turn into soil?

Rocks turn into soil very slowly as rain, ice, plant roots and rivers break them into smaller and smaller pieces. These rock bits mix with rotted plants and animals, and making just one centimetre of soil can take hundreds of years.

What is organic matter in soil?

Organic matter is anything in soil that was once alive, such as dead leaves, twigs, roots and animal remains. Worms, minibeasts and fungi break it down into tiny dark crumbs that make soil richer for plants.

What age is this soil game for?

It is made for children aged 7 to 9 and follows the Year 3 Rocks unit of the national curriculum in England. Older children can also use it as a quick refresher on how soil forms.

What does the soil game include and how long does it take?

The game has a short warm-up, five chapters and an eight-question challenge, and takes about 40 minutes to play through. Children dig up soil, break a boulder, help worms rot leaves, build soil layers and test soil in a jar.

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