Our beautiful planet has many different landforms. There are mountains and valleys. There are plains and plateaus. There are rolling hills and deep canyons. Earth's surface is always changing. The surface is constantly being worn down by erosion. Erosion is the process of wearing away or carrying away materials from Earth's surface. It comes from the Latin words meaning "to eat away." Erosion eats away Earth's surface.
There are four main agents of erosion. Moving water, wind, gravity, and ice wear away or break up rocks, sediments, and soil from the land's surface. When these materials are deposited or dropped in new places, it is called deposition.
Erosion and deposition work together. They change landforms. Sometimes they create new ones. Flowing water wears away soil and rock like sandpaper wears away wood. Streams and rivers carve gullies and canyons through the land. Ocean waves pound rocks into small grains called sand. Wind carries away soil and sand. They are deposited in other places. Mountain glaciers slide down slopes. As they move, glacial ice plucks away soil, sediment, and rocks. Glaciers carve out mountain valleys.