Hello, students, today we are going to learn chapter 9, that is Agents of Erosion.

Students, we have studied in previous chapters about Endogenous processes and Exogenous processes. So, let us revise, once again what are Exogenous processes and Endogenous processes?

Students, endogenous processes affect earth’s surface, but it originates in the interior of the earth. Earthquakes, volcanoes, formation of mountains and continents these are all the effects of endogenous processes. Whereas exogenous processes occur on the surface of the earth and bring about changes in the landscape, weathering, erosion, transportation and deposition are the effects of exogenous processes.

Students, of these exogenous processes, we have studied the process of weathering in the last chapter. So, in this chapter we shall study the processes like erosion, transportation and deposition. So, students let us try to understand these processes in detail.

So, first process, that is erosion. Students, erosion means wearing of the rocks. This wearing can take place due to friction and scraping. Friction means action of one surface or object rubbing against another. Means the movement of wind, water and ice over rocks causes friction and it results in the wearing of rocks and this leads to erosion of rocks. So, students, erosion is caused by river, wind, ground water, glacier and sea waves. Students, the work of river, winds and glacier is controlled by the climate of the region, whereas, sea waves and ground water work in the region wherever they exist. So, students, we understood the processes of erosion.

Let us learn now, what is denudation. Students, you know that rivers erode sediments from the rocks in the initial stage and then river transport the sediments over a long distances and this river deposits sediments in the form of the fine soil in the final stage of the river. So, this entire process of erosion, transportation and deposition of rocks in the form of a fine soil is called denudation.

Students, so we know that who are the agents of erosion? Wind, rivers, glaciers, sea waves and ground water but out of these, in this chapter we shall study the work of river, wind and glaciers.