Changing Land
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Physical weathering occurs as seawater crashes against these rocks. The water slowly wears away the rock.
© www.istockphoto.com/Kirill Trifonov
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A heavy rain fell on a mountain. Water flowed down its slopes and ran into a stream. The water was dark with silt and sand. It picked up this sediment as it flowed over the ground. The stream carried away a little bit of the mountain that day.
Land seems never to change. However, it does change very slowly over time. Water, ice, and wind break apart rock and carry it away. The breaking apart of rock is called weathering. The picking up and carrying away of the pieces is erosion. Over a long time, weathering and erosion can wear down mountains, fill in valleys, and cut deep canyons.
