2026–27 · Backup lesson · Spring 2027

Test Ground Cover for Soil Protection

Adult extension of: Erosion: What Protects Soil?

Unscheduled alternative · available resource

Compare runoff from matched bare and mulched soil trays under the same gentle simulated rainfall. Use visible soil movement to choose a small garden-protection action while recognizing that a tray cannot reproduce an entire landscape.

Curriculum skill focus: Earth science, cause-and-effect, environmental problem-solving, observation

01 · Learning

Objectives

Set up a comparison in which ground cover is the planned difference.
Observe runoff volume and visible sediment separately.
Use the result to suggest an appropriate soil-protection practice.

02 · Preparation

Materials

Two matching shallow trays with drainage outlets; equal amounts of clean soil; clean mulch or leaf cover; fixed low supports; identical catch containers; watering bottle with gentle shower cap; measured water; timer; towels; observation sheet.

03 · Practice

Adult project

1
Identify a real place where soil has washed away, using a photograph if needed. Predict whether bare or covered soil will move more, and select a setup, pouring, recording, or observation role.
2
Prepare both trays with the same soil amount, starting moisture, compaction, and gentle slope. Cover one with an even measured layer of mulch, leave the other bare, and place catch containers under the outlets.
3
Add the same water volume to each tray over the same time from the same height. Use a gentle shower pattern rather than a concentrated jet, and keep trays stationary during the test.
4
Observe channels, moved particles, runoff color, and collected volume. Photograph from the same angle; allow catch water to settle before comparing visible sediment without claiming color alone gives an exact soil mass.
5
Compare results and discuss what the mulch may have changed, including droplet impact and water speed. If using rooted turf in a later trial, explain that roots introduce an additional difference rather than claiming today’s mulch trial tested roots.
6
Choose a suitable local action, such as covering exposed container soil or seeking advice about a washout. Do not redirect drainage onto a path or property; dispose of sediment in a soil container and clean the tray.

Evidence & interpretation

What the investigation shows

Erosion is the movement of soil or rock material by agents such as flowing water or wind. Mulch reduces raindrop impact and can slow surface flow; living roots may stabilize soil, but that mechanism is not demonstrated by loose mulch alone.

Practical connection

Why this work matters

Ground cover can help protect planting areas and keep soil out of drains and walkways.

Participation by choice

Individual access options

Direct the rainfall pattern or compare photographs while another person pours.
Use high-contrast catch containers, enlarged runoff images, or a spoken account of water and soil movement.
Choose a dry planning role, use a long-handled scoop, or decline soil and water contact; pause the test whenever needed.

Review & transfer

Reflect on the work

Which observation supports your recommendation?
What important outdoor condition was missing from the tray model?