Erosion is the carrying away of rock, sand, or soil by nature. Weathering breaks down rock into smaller pieces. Then erosion carries the pieces to new places. Water, ice, waves, and wind move the pieces from weathering. Sometimes the pieces are carried far away from where they started out.
When the pieces are laid down, this is deposition. When hard rains cause rivers to rise, the water often erodes and carries away soil and rocks from the sides of the river. The soil and rocks are deposited in a new place.
Most of the time, erosion is a slow process. It may take millions of years for erosion to change Earth's surface. The Grand Canyon was formed by three million years of erosion.