Geography

Welcome to our Geography video tutorials.  In today's lesson we're going to focus more on the Agricultural activities more specific types of Agriculture in Namibia and their characteristics! Enjoy the tutorial session by following the link  https://drive.google.com/file/d/1jQ-sTpKYnHR6ImkT6VJe7iE5wEyxTnWO/view?usp=drivesdk

  Topic 10: Marine process Characteristics of the waves CONSTRUCTIVE DESTRUCTIVE - DESTRUCTIVE - Longer wave length - Shorter wave length - Builds the coast line - Erodes the coast - Lower wave height - Higher wave height - Wave are flatter - Waves are steeper. etc. - More deposition than erosion - More erosion than deposition - Stronger Swash and Weaker Backwash - Stronger backwash and Weaker Swash - Lower frequency : 6 – 8 per minute - Higher frequency: 12 – 14 per minute Name and describe the erosional processes of wave action such as corrasion, hydraulic action, corrosion and attrition Hydraulic Action / Pressure: • When waves smashes against a rock, the force of the water compresses air trapped in crack of the rock- enlarges a weakness in the rock. Corrasion / Abrasion • Materials such as sand and stones carried by waves is used to scour and scrape rocks in the way. Attrition • The material carried by the waves grind down other materials in the wave Corrosion/Solution...

  Topic 9: wind processes Name and describe the wind transport processes Wind transport material in the following ways : 1. Suspension: very fine particles are lifted into the air and carried over great distances. 2. Saltation: rough, grainy sand particles bounce along the ground. 3. Surface creep: larger particles like small stones and pebbles roll along the desert surface by strong wind. Describe and explain the landforms and features associated with wind deposition Huge quantity of wind-blown sand is deposited to form dunes. Physical features of Barchans • Crescent shaped dunes/half-moon shaped • It has two horn pointing in the direction of the prevailing wind. • About 30M high/400M wide • Windward side is gentle and the leeward side is steep and concave shaped. Are you wondering on what this might be? Follow the link to learn and study more about wind processes https://youtu.be/wT-TnooJNio?si=YzvT2HBRmsR-JeK8

  Topic 8: Wind process Name and describe the erosional processes of wind action Wind erodes in the following ways: 1. Abrasion: rock particles rub against each other and wear away. 2. Deflation: wind blows away loose material leaving a depression. 3. Attrition: sand and rock particles carried by the wind are blown against rock surfaces Describe and explain the landforms associated with wind erosion 1. Rock pedestals: • Made of Horizontal layers of rock with varying resistance are exposed to the wind. • Softer layers will be eroded easily while harder layer will remain. • Have mushroom shape • Lower part is eroded more, looks thinner. Example of rock pedestals are available here:  https://youtu.be/uH_TbsJc2ds si=EpKTxuYrMamfxOai 2. Deflation hollows/oases • A deflation hollow is a type of landform found in arid and semi-arid regions. • It occurs when loose surface materials are scooped out. • Sometimes, a deflation hollow may reach the water table. • As the water slowly fills...

 Topic 7: River erosional landforms Formation of Ox bow lake • Form at the lower course of the river where meander become wider. • Erosion on outer/concave bank of meander, • Deposition on the inner bank, • Increase size of meander, narrow its neck, • Eventually river breaks through, • Creates a temporary island, • Short cut through meander neck becomes main channel, end of former meander silt up. Cut off/ ox- bow lake Formation of a meander • Meander is a bend in a river • It’s a result of erosion and deposition • Resistant rock layers cause the river to change its course • Meander forms as moving water widens the valley • Slower flowing water, on the inner banks, less energy and will deposit silt forming a slip off slope • Faster flowing water, on the outside bank cause more erosion (e.g. hydraulic action, abrasion) forming a cliff Cross section of the meander

  Topic 6: River processes Section of the river Key concepts: Drainage basin: the area the river system flows through • Watershed: high – lying area separating drainage basin • The river system: A river and all its tributaries • Tributaries: smaller River that flows into a larger river. • Long profile of a stream: the fall of the river over its length or the height of the river over its length. • Catchment area: it’s a high lying area that catches precipitation and drains it into the river. • Distributaries: When a river breaks up into smaller streams at the mouth of the river. • River load: materials or debris carried/disturbed by the river e.g. stones, rocks… • Wetted perimeter: part of the river channel that is in contact with water e.g. banks and river bed. • Discharge: amount of water that moves past a particular point in a river. Measured in cubic metre per second (cumecs) Processes taking place in a river 1. Erosion of materials 2. Transportation of materials 3. Deposition ...