Presentation on theme: "Rocks and Weathering Chapter 2 Section 1 Pages 38 - 45."— Presentation transcript:
Rocks and Weathering Chapter 2 Section 1 Pages
Objective: Explain the agents of mechanical and chemical weathering and analyze the factors that affect the rate of weathering. Weathering: The process that breaks down rocks and other substances at Earth’s surface. Erosion: Is the movement of rock particles by wind, water, ice, or gravity. Uniformitarianism: This principle states that the same processes that operate today operated in the past.
Mechanical Weathering: Breaks rock into smaller pieces. Freezing and Thawing Ice Wedging: Wedges of ice in rocks widen and deepen cracks. With repeated freezing & thawing, cracks expand until pieces of rock break off. Release of Pressure Plant Growth Animal Actions Abrasion: The grinding away of rock particles carried by Water, ice, wind, or gravity.
Chemical Weathering: A process that breaks down rock through chemical changes. It produces rock particles that have a different mineral make-up from the rock they came from. Causes of Chemical Weathering: Action of water: Oxygen Oxidation: When iron combines with oxygen in the Presence of water. The product of this is RUST. Carbon Dioxide Living Organisms Acid Rain
The most important factors that determine the rate at which weathering occurs are the type of rock and the climate. Permeable: A material that is full of tiny, connected air spaces that allow water to seep through it. Both chemical and mechanical weathering occur faster In wet climates. Chemical reactions occur faster at higher temperatures. That’s why chemical weathering occurs more quickly in Hot and wet climates.