Bill Nye is obssessed with erosion and explains that rocks change over time. He explains what causes weathering (although he calls it erosion): water, ice, wind, sand, and chemicals. He illustrates the process of erosion in his lab.
The narrator explains how sedimentary rocks form: from sediment deposited in water through the process of weathering and erosion. He also explains the layers of sedimentary rock, which include sandstone, limestone, and conglomerates.
Sabrina explains how the earth changes using seasons and landforms as examples. She illustrates how landforms form and change over time by mentioning plate tectonics, erosion, and weathering. She uses famous examples of gradual change (The Grand Canyon and The Old Man of The Mountain) as well as examples of quick change (Mount St. Helens) to stress that the earth changes in ways that are both noticeable and not so obvious.