How its surface changes

Episode of Series “Understanding Our Earth”. Explains the slow but constant changes in the surface of the earth by showing the erosive effects of water and wind upon a recently excavated mound of raw earth. Includes scenes of the eruption of the Paracutin Volcano, the Grand Canyon of the Colorado River, and a rocky mountainside, pointing out the geologic evidence of forces which continue to build up and wear away the surface of the earth.