Geography

  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 ...

  Topic 5: weathering Name and describe types of weathering  Physical/mechanical weathering a) Exfoliation • It’s a result of temperature differences e.g. in hot desert regions where it’s very hot during day and very cold at night • The constant heating and cooling of rocks cause them to expand (day) and contract at night • This put the top of the rock under stress and crack appear • Eventually the outer layer of rock peel away forming a dome (exfoliation dome). • This process is called exfoliation b ) Frost shattering/Freeze-thaw action • Water may fill cracks in the rock. • At night water freezes and expands • During the day the ice thaws or melts • The constant freeze-thaw action deepens and widens cracks and shatter the rock. • The rock fragments are moved down the slope to form scree Chemical weathering • Chemical weathering is the result of rock undergoing a chemical change. • It’s most rapid in moist, warm region where rocks have already been broken up by physical weath...

  Topic 4: Earthquakes Explain how earthquakes are formed and their impact on human beings and the environment An earthquake is the shaking of the Earth’s surface due to a sudden release of energy by plate tectonics which creates seismic waves. Focus : Point of origin underground where earthquake occurs in the earth’s crust. Epicentre : Point on surface directly above the focus where most damage happens. • Magnitude : Intensity of earthquakes Types Seismic waves :   P waves pass through the earth crust from focus to the surface.   L is when the waves reach the surface and it cause most damages. How earthquakes are formed • Occurs when two plates collide or move past each other. • Edges of the plates are not smooth, • Plates lock and stuck against each other • Pressure/ friction builds up in rocks • Pressure is released, rocks slip and huge amount of energy is suddenly released (seismic shock waves) Follow the link: https://youtu.be/4_4E2D2jAWE?si=V6FjbrAQqw-xOcbx ...

  Topic 3: volcanoes Positive effects of volcanoes on human beings Minerals mined for industrial use • Ash form fertile land for Agriculture • Geothermal power may be generated • Geyser/hot springs favour development of resorts for tourists Positive effects of volcanoes on the environment • New landforms are created e.g. volcanic island (green land) • Add of lava and ash to the soil and improve soil fertility. • Bigger mountains are formed/more high land. Negative effects of volcanoes on human beings Short term effects of volcanoes • Destruction of houses and buildings • Lava and ash reduce visibility • Destruction of crops and farm land by lava flow • Mudflow due to ice melting on top of volcanoes trap people and cover roads Long term effects of volcanoes • Injuries and Loss of lives • Ash and toxic gases can cause breathing problems • Cause water borne diseases as water may be contaminated by ash. • Damage of ozone layer can cause skin cancer. The dog is burned by the lava, imag...

  Topic 2:Types of plate margins and plate movements • Diverging/ constructive plate margins: when two plates are moving away from each other Features of constructive • A gap/space is created. • Due to heat and pressure, magma flows up to fill the gap. • When magma cools down and solidifies it creates new landforms (form new crust/land) • Converging/ destructive plate margins: when two plates move towards each other and collide (leads to earthquakes and volcanic eruption) Features of destructive plate margins When oceanic and continental meet, • the heavier, denser oceanic crust is forced down into mantle at subduction zone (area where oceanic plate is forced down). • Heat and pressure/friction from mantle cause the oceanic crust to melt into magma. • Molten material forced up through cracks (deep sea trenches) to form volcanic eruption. • Earthquakes are common here • Conservative/transform plate margins: it is when plates slide slowly past each other in opposite direction or i...

Let's understand geography content with improving our learnin by practicing on few topics.  Enjoy.  Topic:1  Earth structure  The diagram shows internal structure of the earth  four layers of earth 🌎 1.   The crust:  is a thin outer layer of solid rocks.  It is between 6 to 90 km thick. The crust is divided into two parts. A) Oceanic Crust (SIMA)  made up of Silicon and Magnesium) B) Continental Crust (SIAL) made up of Silicon and Aluminium. 2. Mantle • it is the thickest layer of the earth, covering up to 2900 km. • It is very hot reaching 5000°C. • Materials inside mantle are in a semi-molten state closer to the crust and molten near the core aallowing it to move or flow. • These molten rocks are called magma and it forms hard rocks when it cools and solidify. 3. The outer core • it is about 2000 km thick. • It is very hot and denser. • It is in a molten state. 4. Inner core • it is about 1200 km thick • It is extremely hot, but it is in ...