All lessons › Shaping the land › Lesson 3
Australian primary science · Year 5 · Lesson 3 of 3
Cover the ground
Inquiry question: Does a cover of leaves protect soil from being washed away by rain?
Check practical materials
Fair testing
What students learn
Rain falling on bare soil loosens and carries it away (erosion). A cover of plants or leaf litter breaks the fall of raindrops and slows the water, so less soil is eroded.
Success criteria
- I can plan a fair test with one variable changed.
- I can measure gully depth and how far soil travelled.
- I can use my results to explain how ground cover reduces erosion.
Preparation and materials
Before this lesson: Students know erosion carries soil away and that plants can hold soil (lessons 1 and 2).
- Shallow trays (baking trays, foil trays or plastic tubs) — 13
- Garden soil, slightly damp, collected by the teacher (not potting mix) — 1 bucket (about 4 cups per pair)
- Plastic cups with 10 small holes poked in the bottom by the teacher — 13
- Measuring jug or cup (to measure 1 cup of water) — 13
- Leaves, grass clippings or leaf litter — 1 bag
- Books or blocks to prop up one end of the tray — 13
- Rulers — 13
- Paper towel and newspaper — 1 roll and a pile
Teacher setup
- Poke 10 small holes in the bottom of each cup with a skewer (teacher only).
- Collect slightly damp garden soil with gloves (no potting mix or compost), and remove sticks and stones.
- Collect leaves or grass clippings.
- Cover tables with newspaper, or work outside on a flat area.
- Print one investigation record per pair.
Safety and adaptations
- The teacher collects the soil and pokes the holes.
- Wash hands with soap after handling soil; don’t touch your face while working.
- Students with cuts on their hands wear gloves or cover the cuts.
- Wipe up spills straight away so no one slips.
Review your school policies and curriculum requirements before teaching.
How to investigate
The lesson sequence should leave pupils with evidence to interpret, not only an activity to finish.
- Pairs write their fair test plan.
- Make two equal mounds of soil (2 cups each) at the high end of the tray, then prop the tray on a book.
- Cover one mound with a layer of leaves; leave the other bare.
- Pour 1 cup of water through the holey cup over the bare mound from 20 cm high, moving it slowly over the mound. Repeat for the covered mound.
- Measure the deepest gully (mm) and how far soil travelled down the tray (cm), and note the colour of the runoff.
- If time allows, repeat with a fresh mound.
Teacher modelling prompt
Show a tray with two soil mounds. Think aloud: “I will change only the cover: one mound bare, one covered with leaves. Same amount of soil, same slope, same cup of rain poured from the same height. I’ll measure the deepest gully and how far the soil travelled.” Demonstrate pouring evenly through the holey cup.
Record and explain evidence
Recording question: Does a cover of leaves protect soil from being washed away by rain?
| Mound | Cover | Deepest gully (mm) | How far soil travelled (cm) | Runoff colour (clear, brown, very brown) |
|---|---|---|---|---|
| ________________ | ________________ | ________________ | ________________ | ________________ |
Example recording headings; record actual observations, including inconclusive results.
Discussion prompt
What did you observe that supports either claim?
Check understanding
What should pupils know? Explain how rain causes erosion of bare soil.
Explain with evidence: Use your results to explain why the covered mound lost less soil.
Apply the idea: A farmer’s paddock has bare soil on a hill before the wet season. What would you advise, and why?
Teacher answer guidance and saved classroom work are available through the main lesson experience where supported.