L4 - Weathering (No Video).pptx

Year 8 Geography: Landscapes and Landforms LO: To understand how weathering affects landforms  Starter Take a close look at the three images. What has happened? Presentation title 2 De...

Year 8 Geography: Landscapes and Landforms LO: To understand how weathering affects landforms  Starter Take a close look at the three images. What has happened? Presentation title 2 Definition – Write in your book Weathering is a process where rock is worn away; broken down or dissolved into smaller and smaller pieces by water, heat and cold. 3 Types of weathering Weathering can be broken into two categories: Physical or Mechanical Weathering: The break down of rocks caused by physical processes Chemical Weathering: The break down of rocks caused by a change in their chemical make-up. 4  Pair work In pairs, you will all research what causes mechanical weathering and the types of chemical weathering. Each person will be responsible for one of the following; Mechanical weathering causes: temperature, ice, roots and plants Chemical weathering types: hydrolysis, carbonation, oxidation You will need to write a summary explaining your given concept and include a visual example on your shared doc (images or diagrams) P.34-37 in your 5 Causes of Mechanical Weathering Mechanical Weathering is caused by physical forces breaking rocks into smaller pieces without changing their chemical composition. The key causes of mechanical weathering include: 1. Temperature (Thermal Expansion): Repeated heating and cooling cause rocks to expand and contract, leading to cracks and eventual breakage. 2. Ice (Frost Wedging): Water enters cracks in rocks, freezes, and expands, causing the rock to break apart 3. Roots and plants: Roots from plants or animals can grow into cracks in rocks, widening them and causing them to fracture. 4. Abrasion: Wind, water, or other natural forces 6 Types of Chemical Weathering Chemical Weathering involves the break down of rocks caused by a change in their chemical make-up. Types include: 1. Hydrolysis: The reaction of minerals with water, leading to the breakdown of rock. For example, granite rock changes to softer clay through hydrolysis. 2. Oxidation: when oxygen combines with other elements in rocks, new types of rock are formed. These new rocks are generally softer 3. Carbonation: rainwater contains carbonic acid, this reacts with minerals in some rocks, causing the rocks 7 to weather. After weathering happens, erosion also is involved – but how? 8 Erosion the process of moving + transporting weathered materials (soil, rocks, and sediments) from one location to another, typically by natural forces such as wind, water, ice, or gravity. Erosion follows weathering, as the broken-down material is carried away from its original location. Erosion results in the displacement of materials across various landscapes 9 Weathering v Erosion Weathering = the process of breaking down rocks, minerals, and soils through physical, chemical, or biological means. It occurs where the rock is located and does not involve movement of material. Erosion = the process of moving + transporting weathered materials (soil, rocks, and sediments) from one location to another, typically by natural forces such as wind, water, ice, or gravity. Erosion follows weathering, as the broken- down material is carried away from its original location. Erosion results in the displacement of 10 Write and Draw Write Explain how weathering and erosion are interconnected in the formation of the Antelope Canyon Draw Copy Source 1 – “The process of erosion” from page 34-35 into your book – don’t forget to annotate your diagram 11 12 Extension Create a fact sheet for one of these places with annotated photos and information on which type of weathering was responsible for its creation. 1. Limestone Case Study - Madagascar Stone Forest 2. Uluru (Ayer's Rock), Australia 13