Geography

  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 ...