External Land Forming Processes and Weathering

Syllabus tag: KCSE | Geography | Form 3 | Topic 20 External Land Forming Processes

Lesson objectives

By the end of this topic, you should be able to:

• Define external land forming processes and distinguish weathering from erosion.
• Explain the factors influencing weathering.
• Describe the processes of mechanical, chemical and biological weathering.
• State the significance of weathering to human activities and the environment.

Summary

External or exogenetic processes originate outside the crust and generally wear the land down. Weathering is the breakdown of rocks in situ, that is without movement — which is what distinguishes it from erosion. It is mechanical, chemical or biological, and its type depends chiefly on climate.