Changes around Us (Erosion)

Back to: Basic Science Primary 5

TOPIC: EROSION

INTRODUCTION: In previous classes and lessons, we learnt about our environment and what our environment consists of. We have learnt about sources of pollution, how to prevent or control pollution of air, land and water. Our environment often undergoes different kinds of changes some are natural while others are caused by human activities. Erosion is one of those changes. In this lesson, we will be focusing on types of erosion and their causes.

 

Meaning of Erosion

Erosion is the gradual washing away of the top soil of the earth’s surface. When erosion occurs, the top soil is washed off and carried away by water or wind. The soil is washed away by these natural occurrences because it is exposed. The exposure of the topsoil is brought about by the many activities of man. Man engages himself in numerous activities in other to explore his environment for further research or in search of food, mineral resources and ultimately economic development.

There are four types of erosion, namely:

• Gully erosion
• Sheet erosion
• Splash erosion.
• Rill erosion.

 

           

Causes of Erosion

There are two main causes of erosion. They are

• Water (rain and ice glacier)
• Wind

Water: when water in the form of rainfall or flood flows continuously on the earth’s surface over a period of time, it washes away the loose particles of the soil. sometimes the effect is not seen immediately.

Ice: when ice or snow accumulated on a high-altitude melt, it trickles down gradually into the lower region of soil and rocks and washes away the loose particles of the top surface of the rock or soil.

Wind: When a strong wind such as a whirlwind, hurricane or tornado blows, it carries away the loose particles of the top soil.

 

EVALUATION:

1. What is erosion
2. List four types of erosion.
3. Mention the two main causes of erosion.

 

 

 

 

 

 

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