RELIEF FORMATION : EROSION, TRANSPORT AND DEPOSIT

What is erosion?

Erosion is the wearing away of the land by forces such as water, wind, and ice. Erosion has helped to form many interesting features of the Earth’s surface including mountain peaks, valleys, and coastlines.

What causes erosion?

There are many different forces in nature that cause erosion. Depending on the type of force, erosion can happen quickly or take thousands of years. The three main forces that cause erosion are water, wind, and ice.

Erosion by Water

Water is the main cause of erosion on Earth. Although water may not seem powerful at first, it is one of the most powerful forces on the planet. Here are some of the ways that water causes erosion:

  • Rainfall – Rainfall can cause erosion both when the rain hits the surface of the Earth, called splash erosion, and when raindrops accumulate and flow like small streams.
  • Rivers – Rivers can create a significant amount of erosion over time. They break up particles along the river bottom and carry them downstream. One example of river erosion is the Grand Canyon which was formed by the Colorado River.
  • Waves – Ocean waves can cause the coastline to erode. The shear energy and force of the waves causes pieces of rock and coastline to break off changing the coastline over time.
  • Floods – Large floods can cause erosion to happen very quickly acting like powerful rivers.

                                                                                        

Erosion by Wind

Wind is a major type of erosion, especially in dry areas. Wind can erode by picking up and carrying loose particles and dust away ). It can also erode when these flying particles strike the land and break off more particles .

Erosion by Glaciers

Glaciers are giant rivers of ice that slowly move carving out valleys and shaping mountains.

Other Forces

  • Living organisms – Small animals, insects, and worms can add to erosion by breaking up the soil so it is easier for the wind and water to carry away.
  • Gravity – The force of gravity can cause erosion by pulling rocks and other particles down the side of a mountain or cliff. Gravity can cause landslides which can significantly erode an area.
  • Temperature – Changes in temperature caused by the Sun heating up a rock can cause the rock to expand and crack. This can cause pieces to break off over time and lead to erosion.

How have humans caused erosion?

Human activity has increased the rate of erosion in many areas. This happens through farming, ranching, cutting down forests, and the building of roads and cities. Human activity has caused about one million acres of topsoil to erode each year.

Science Worksheet_ types of erosion

Science Worksheet_ erosion and weathering

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