BHU+1215+Physical+Geography+I

**(// SCALING THE HEIGHTS OF EDUCATION //)** **MAIN CAMPUS – THIKA** ** BHU 1215: PHYSICAL GEOGRAPHY I ** **(Class of January – April 2017) – ON 16/02/2017 – TEACHER PHYSICALLY IN MALINDI – Breeze Point Hotzone WIFI)**   **__Dr. Kennedy Obiero__**  - I am wishing the whole class a “** Happy Valentine **”. - I will not be able to physically attend the class of 16/2/2017 - **__ Reason __** – I am away in __Malindi__ not for a ‘Happy Valentine Holiday but **__for research__** which is a core business not only for Geographers but also for scholarship. - Kindly accept my apology and use the attached material for the class. I have used this method several times while I am out of Nairobi or out of Kenya. - Virtual learning is no longer an option but part of life. - The material can be accessed in Cyber Cafes and interesting even on your phones using bundles or some money at the Cyber. - Thanks.
 * MT KENYA UNIVERSITY **
 * (__ VENUE __– PREFERABLY COMPUTER LAB with internet. CYBER OR ON-LINE FACILITY – Includes phone and bundles)**
 * General Introduction**

- Ensure you have internet whether at the Cyber, University Computer Lab. Or using your phone - Visit my MKU Nakuru Campus Website: //- This is the home page// //- Read the page carefully// //-// **__FOLLOW IN STRUCTION__** //- Select and open BHU 1215 Physical Geography I// //(a) You choose to read on-line and make notes or// //(b) You can copy the material to MS-Word, print and read off-line//
 * INSTUCTIONS – THIS CLASS IS REACHING YOU ON-LINE. **
 * (Methodology without Physical barriers. I have used it in Zanzibar, Dar es Salaam in Tanzania and Kenya and even in more than one University) **
 * httt://kennedyobiero-mku-nakurucampus.wikispaces.com// **

//**WARNING**: This material should not be accessed during CAT or EXAMINATION as it will amount to irregularity and academic dishonesty.// //**THE MATERIAL STARTS HERE**//

//** THE INTERNAL STRUCTURE OF THE EARTH **// //** CORE **// //- Already discussed the earth’s crust and the mantle. Incase not launch the complain in class when we meet next week.// -**THE CORE** - This is the centre of the earth and extends about half way to the surface from the centre of the earth. - Its radius is about 3400 km. - It has much high density and it is dominated by a mixture of iron and nickel. - The physical state of the core is uncertain because the high pressure and temperatures that characterize the core cannot be simulated (experimented) in ordinary laboratory conditions. - The core is divided into two; the outer core and the inner core. It is argued that the inner core is in solid state at high temperature but not melting because of the high confining pressure. //**ENDOGENIC VERSUS EXOGENIC PROCESSES**// //**Endogenic Processes**// //- These are processes that take place or originate in the earth’s but their effects are not only felt in the interior but also reach and even devastate the earth’s surface.// //- They are driven by the earth’s internal energy.// //- For you to explain very well, read about the internal structure of the earth particularly the ASTHENOSPHERE part of the mantle// //- The endogenic processes include: faulting (cracking of the earth’s crust), vulcanicity )flow of hot molten materials into and onto the earth’s crust), folding (bending of crustal rocks), tremors (minor vibrations of the earth’s crust) and earthquakes (rapid vibrations of crustal rocks).// //- The processes lead to the formation of features both in the earth’s interior and on the earth’s crust.// //- These topics were covered well in our High School Geography but you can still read on them.// //**Exogenic processes**// //- Unlike endogenic processes occurring in the earth’s interior driven by the earth’s internal energy, these occur on the earth’s surface and are driven by solar energy and force of gravity.// //- They include; weathering, erosion, transportation, mass movement and deposition. This leads to the formation of a variety of features by the said processes on the earth’s surface.// //- Some of these processes may be read in Physical Geography II but also read on them in addition to what you studies in high school.//

**THE THEORY OF PLATE TECTONICS** - The theory holds that the earth’s crust (SIAL and SIMA) is divided into a number of blocks also known as plates that float on the molten part of the mantle (**asthenosphere**). - The plates include; Eurasian, African, Arabian, South American plate, North American plate, Pacific plate, Australian plate, Nazca plate among others. //*(**__Will provide copy of plates in class next week. Please remind me__**)*// - These are major plates and minor plates. - The convectional currents generated by the molten asthenosphere makes the plates mobile. - The plates may move towards each other, away from each other or slide past one another. - The movement of the plates is responsible for endogenic processes such as faulting, volcanic activity, earthquakes, tremors and folding. - If two continental plates converge, since they are both light in density bend upwards forming a folded landscape (mts.). - If a continental and an oceanic plate converge, the oceanic plate, being denser sinks beneath the continental plate forming a **subductio**n zone and the process is known **as subduction.** - When two plates drift away from each other, faulting takes place and a Rift Valley such as the East African Rift Valley is formed. - As the plates drift apart, hot materials from the mantle (asthenosphere) will find their where into or onto the earth’s crust forming volcanic features. - If a similar process occurs in the oceans, hot materials will flow and cool on the **ocean floor** leading to a process known as **ocean floor spreading**. - Excessive flow of materials will form volcanic islands. - Four plate margins common; constructive, destructive, collision and conservative. These are plate boundaries where two plates converge. They are areas of a lot of crustal movements and therefore crustal instability. There are four different types of margins, which include; a) **Constructive margins** - where two plates move away from each other (divergent plates). New crust is formed as materials spread to the surface. Leads to ocean floor spreading on the ocean and building of volcanic mountains on the land. On the ocean it can lead to the formation of volcanic islands. b) **Destructive margins** - where continental and oceanic crust converges. Continental crust is forced to dip downward forming a subduction zone. Part of the crustal materials especially the subducted oceanic crust is destroyed by the high temperatures of the asthenosphere. This forms the **deepest parts of oceans known as trenches**. c) **Collision plate margins** - two continental plates collide. Both are less dense or light. They are forced to bend upwards forming fold mountains e.g., Atlas and Alps. d) **Conservative/passive margins** - two plates move sideways or slide past each other. Leads to earthquakes and tremors. Plate margins are very unstable areas associated with volcanic activities, earthquakes, faulting, folding among other endogenic processes. //**WEGNER’S THEORY**// - “School children frequently bemuse themselves by mentally piecing together the coastlines of Africa and South America and concluding that they fit fairly”. - The Wegner’s theory is an extension of the Plate Tectonics Theory. The theory was put forward by a German Geomorphologist, known as Alfred Wegner. EXERCISE – COMPULSORY (4 MKS) //(a) Look for a world map// //(b) Trace the map on a paper// //(c) Photocopy or have a duplicate of the map// //(d) Using a pair of scissors, cut the map into different continents// //(e) The Island of Madagascar should be a separate peace.// //*THESE WILL BE USED IN THE NEXT CLASS*// //NB – FOR YOU TO ATTEND NEXT CLASS, YOU MUST HAVE COMPLETED THIS EXERCISE//

//GOD BLESS YOU.//
 * ‘No better baggage on a journey than much knowledge’ . A Norwegian saying. //**

The Lesson of 23/2/2017