Week 17 · Axis 3, Chapter 1 The Nile I Know (B) · 3 lessons
3
Sand, soil and erosion
Discover P2 Term 2: Axis 3, Chapter 1
GoalTell how wind and water move sand and soil, and explain what erosion is.
New words
erosion · when wind and water carry soil and rock awaydune · a hill of sand made by the windsoil · the top of the ground, made of tiny bits of rock and dead plants
Explanation
There is a lot of sand and rock in the deserts of Egypt. Soil is made of tiny bits of rock and dead plants. Wind can carry sand and pile it up into hills called dunes. Water can carry soil and small stones down a slope and make little channels. When wind and water carry soil and rock away, we call it erosion. Erosion slowly changes the land. Plants help, because their roots hold the soil in place.
Worked examples
Jana sees ripples in the sand on a dune. The wind has moved the sand.
After a heavy rain, Youssef sees muddy water running down a slope. The water carries soil with it.
A hillside with plants keeps its soil. A bare hillside loses soil more easily.
Class activity
Erosion test with a grown-up, outside or over a big tray. Make two small hills of dry soil or sand. Wind test: stand back and blow gently across the first hill through a straw. Do not blow towards anyone’s face. Water test: slowly pour a little water from a cup over the second hill. Look after 30 seconds and after 1 minute. Draw what happened to each hill. Wash your hands.
Practice
1
What is erosion?
Wind and water carrying soil and rock away.
2
What can the wind build from sand?
Dunes, which are hills of sand.
3
Which one can carry soil down a hill? Say the letter.
