Learning Objective Differentiate between physical and chemical weathering

Learning Objective: Differentiate between physical and chemical weathering and identify the agents of erosion and deposition by analyzing characteristics of the weathered substances and eroded sediments. Think-Pair-Share: What is the difference between weathering, erosion and deposition?

ÜWeathering: Breaking down rock ÜErosion: Moving rock from one place to another (transporting) ÜDeposition: Where the rock ends up (where it lands)—usually into the mouth of a large body of

Think-Pair- Share Ü Which of the following pictures illustrate weathering and erosion? Why?

ÜWeathering: ÜErosion: ÜDeposition:

Shaping Earth’s surface Ü Through weathering and erosion, Earth’s surface is shaped into different physical features such as mountains, plateaus, hills, valleys and dunes. Ü Mountains that are created by collisions of tectonic plates are being weathered and eroded.

Types OF Weathering Physical weathering Chemical weathering

Types OF Weathering Physical weathering -Rock material does NOT change Ex: Hitting, frost action, scratching (abrasion), breaking from changes in temp. , pressure or living organisms Chemical weathering - Rock material is changed into another substance. Ex: Oxidation (exposure to air), Acid (acid rain), Hydrolysis (Water)

Physical Weathering Ü Frost action: when water seeps into cracks in rocks then freezes and expands causing the rock to crack. Example, pot holes

Physical Weathering-Plant or Root Action

Chemical Weathering Acid rain on limestone Granite Oxidation in

Chemical Weathering-Hydrolysis Ü Feldspar combines with water to form the clay Kaolin. Feldspar Kaolin

Soil - The end product of weathering • Soil- rocks, minerals and organic material • Soil forms layers: The oldest layer at the bottom. horizons.

Factors affecting the rate and type of Weathering Ü 1) Climate: Hot and dry=more physical Cold and wet=more chemical Ü 2) Particle Size/Surface Area: greater surface area &/or smaller=faster weathering Ü 3) Mineral Composition (what rock is made up of)

Erosion • The process by which water, ice, wind or gravity moves fragments of rock and soil.

Erosion Monument Valley, Arizona Sea Arch. Santa (wind erosion) Cruz, California (water erosion)

A. Gravity: AKA mass movements • Materials falling down • Steeper slope=more erosion • Examples of Mass Movements: – Slump – Mud Flow – Landslide – Avalanche (very fast)

B. Wind Erosion: 1) takes place primarily in desserts and beaches. 2) moves small, light-weight particles.

D. Running Water: the most powerful agent of erosion. • Running water rounds and smoothes the rock, making the rock smaller. • Abrasion: process that breaks off pieces of rocks when they bang into something (making it rounder)

C. Glaciers • Glaciers are large pieces of ice. • Moves sediments of ANY size. The white areas show glaciers and ice sheets.

Deposition • Sediment can be deposited by wind, water, glaciers, or gravity. • Deposition in a stream is rapid at the mouth of the stream (where the velocity of the stream suddenly decreases). • Steeper, faster river or stream = more erosion • Most final deposition suddenly occurs in large bodies of water such as likes or oceans.

Deposition by wind and water (stream or river) Sand dunes-wind River-water deposits sediment

Activity-Independent & Group Work • Use your notes to answer the questions on the worksheet in groups. Extension- Use the textbook to answer the following questions: 1 -Describe three landforms that are shaped by weathering and erosion. 2 Explain how the velocity of a stream affects the suspended load (amount of sediment it contains).

Share-Out & Reflection • Let’s share out the answers to the questions. Reflection • How are the processes of weathering and erosion similar? Different? • How does deposition relate to weathering and erosion?