🌍 Soil Erosion Test
Pour water over bare soil and soil with plants and see how plant roots protect the earth from washing away!
🧰 What you need
🔬 Steps
- 1
Fill both trays with the same amount of soil. In one tray, plant grass clippings or small plants — press them firmly so their roots are in the soil.
💡 The more roots the better — grass with intact roots works best. - 2
Leave the second tray with bare soil.
- 3
Tilt both trays at the same angle (rest one end on a book).
- 4
Pour the same measured amount of water over each tray using a watering can.
- 5
Compare the water running off the front of each tray — which is muddier? Which carries more soil?
💡 Collect the runoff in separate containers and let it settle — the amount of sediment shows how much soil was lost.
🧠 The Science
Plant roots are like a net woven through the soil. They bind soil particles together, holding them in place when water flows over them. Bare soil has no such anchor — water dislodges the particles and carries them away in the runoff. This is called soil erosion. Healthy soil with plants loses very little to water — the roots, fallen leaves, and organic matter act as a sponge and barrier. When humans clear forests or over-farm land, the topsoil erodes quickly, making the land infertile and causing muddy floods downstream. Planting trees and ground cover is one of the best ways to prevent erosion.
📚 Related Lessons
- 🌴 Plants in Habitats — Plants have amazing adaptations — cacti store water in deserts, lotus floats in ponds, and pine trees shed snow!
- 🌍 Air, Water and Soil — Air, water, and soil are the three pillars of our environment — all living things depend on them working together!
- 🏭 Types of Pollution — Air, water, and soil pollution harm all living things — factories, vehicles, and waste are the main causes!