Unit: Weathering and Erosion
An old limestone grave marker may show only a faint trace of a name or date; over time acidic rainfall caused the soft limestone to dissolve. Cave systems also form from acid solutions trickling underground. In this concept, you will learn about the different facets of chemical weathering.
“Rock solid” doesn’t mean much, considering the mechanical processes that break down rocks and minerals. In this concept, you will learn how water freezing and thawing, wind-driven sand and other particles, plant roots, and the efforts of burrowing animals can all play a part in the process of weathering.
Erosion by Water
It may have taken millions of years, but the flowing waters of the Colorado River were able to carve a mile down through the rock layers of the Colorado Plateau to form the Grand Canyon. This concept will examine how moving water and the action of glaciers play major roles in erosion.
Erosion by Gravity
Often dramatic and destructive, erosion by gravity moves amounts of weathered rock and soil from a high place to a lower one. Sometimes heavy rain and snowfall contribute, as in landslides, mudslides, and avalanches. In this concept, you will learn how gravity can play a part in the erosion of materials.