How much soil?

Activity

Realise the importance of soil and learn why we should look after this valuable growing resource.

  • Estimated time: 30 minutes
  • Location: Outdoors & Indoors
  • School term: All year round
  • Level of experience: No experience needed
  • Subject(s): Maths, Science, Geography, Social Studies

Learning objectives

  • Understand how little of the Earth’s surface is suitable for food growing 
  • Learn about fractions, pie charts and percentages 

Essential background information

Preparation

Ask your group to list the different words used to describe soil e.g., dirt, mud, earth, ground and sand.

Discuss: Is dirt a good name for soil?

Equipment

  • Soil statistics
  • Apple for each group to demonstrate fractions
  • Sharp knife (only for adult to use)
  • Cutting board
  • Crayons or pencils

Step by step

  1. Ask your group to estimate how much of our planet is made up of soil.
  2. Take a large apple and explain it represents the Earth. 
  3. Using the information sheet, cut up the apple according to the fractions of the Earth’s surface that cannot be used for food growing.
  4. Depending on your group's knowledge and abilities, discuss why crops won’t grow in swamps, hot climates or on rocky sites.
  5. The final section will represent the tiny piece of the Earth where we can grow crops for food (3%). Of this 1/32 segment only the apple skin is used for growing. This represents the fertile upper layer called the topsoil.
  6. Use a graph or pie chart to display the soil statistics.

Hints & tips

  • Look in your lunchbox – challenge pupils to name a food in their lunch that has not come from soil.
  • Use this activity as part of Earth Matters class growing topic.