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Once mountains exist, what starts to break them down?
- Building forces raise the land into mountains.
- Then outside forces begin to break it down .
- This breaking down happens in two steps .
- First the rock is broken — this is weathering .
- Then the pieces are carried away — this is erosion .
What is weathering, and what are its types?
![2.5 Weathering and Erosion - Shaping of the Earth’s - [Teachoo] - Concepts](https://cdn.teachoo.com/169babec-2843-40f4-9a4a-81d8741c258c/fig.-2.8-types-of-weathering-shown-together-physical-weathering-chemical-weathering-and-biological-weathering..jpg)
What are the three types of weathering?
Weathering
breaks rock in place
1. Physical
Rock breaks into pieces
By heat, frost or wind
Example:
Cracks from day-night heat
2. Chemical
Minerals react and change
Water, air or acid act
Example:
Rusting; rock dissolving
3. Biological
Living things break rock
Example:
Roots splitting a rock
Fig. 2.8 — The three types of weathering: physical, chemical and biological
Definition — Weathering
Weathering is the breaking down of rock into smaller pieces on the spot.
It does not involve any movement of the pieces — only the breaking.
It does not involve any movement of the pieces — only the breaking.
What is erosion, and how does it differ from weathering?
| Type | Caused by | Common where |
|---|---|---|
| Water erosion | Rivers, rain, waves | River banks, coasts |
| Wind erosion | Strong dry winds | Deserts, dry regions |
| Glacial erosion | Moving ice | Snowy mountains |
| Coastal erosion | Sea waves | Along the seashore |
Definition — Erosion
Erosion is the wearing away and
carrying away
of soil and rock by natural agents.
Unlike weathering, erosion moves the broken material to a new place.
Unlike weathering, erosion moves the broken material to a new place.
Types of erosion
Fig. 2.9 — Erosion by running water and by wind
What is the full breaking-down cycle called?
How do outside forces reshape the land?
Weathering — rock breaks in place
↓
Erosion — pieces are carried away
↓
Deposition — the pieces are dropped and build new landforms
- So the cycle is break → carry → drop .
- The third step, deposition , quietly builds deltas, beaches and plains.
The full cycle — weathering breaks, erosion carries, deposition drops
How does erosion affect human life?
- Erosion strips away the fertile topsoil farmers need.
- It can wash away land, houses and roads near rivers and coasts.
- It makes hillsides unstable for building and mining.
- So erosion shapes the land but also hurts livelihoods .
🔎 Let’s Explore
Look at the photographs in Fig. 2.9 and note the type of erosion in each. How are farmers affected by erosion caused by water and by wind?
📜 Don’t Miss Out
The
Sindhu-SarasvatB;
civilisation used clever water-management methods —
contouring, bunding, terracing
, dams and canals — to fight soil erosion. The
Zabo system
of Nagaland still uses earthen bunds and check dams on hill slopes to save soil and water.
Related NCERT Questions — try them now
NCERT Question 6 — How are deforestation and erosion associated
How are deforestation and erosion associated with each other? Explain.
NCERT Question 7 — Develop a plan to protect the land
Develop a plan to protect the land in your local area from erosion.
