Physical Environment - Class 6 Social Studies Revision Notes

• Physical Environment
• The Countries of Eastern Africa
  • Position And Size of The Countries of Eastern Africa
• Latitudes And Longitudes
  • Latitudes
    • Characteristics of latitudes
  • Longitudes
    • Characteristics of longitudes
  • Use of latitude and longitudes to locate places
• Map interpretation
  • Interpreting human activities
  • Interpreting drainage features
  • Interpretating settlement
  • Interpreting administration in the area
• Physical Features
  • Relief Physical Features
    • Mountains
    • Plateaus
    • Plains
    • Lakes
    • Rivers
    • Swamps
  • Formation of mountains
    • Formation of Block mountains
    • Formation of volcanic mountains
  • Formation of the Rift Valley
  • Formation of lakes
    • Earth movement processes
    • Volcanic Processes
    • Erosion process
    • River Action
    • Human-made lakes
  • Relief Regions of Eastern Africa
    • The coastal plains and lowlands
    • The plateaus
    • Highlands and mountains
    • The Rift valley
    • Victoria Basin

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Physical Environment

• The physical environment is what is found around us

The Countries of Eastern Africa

• Eastern africa is the region located in the eastern region of africa.
• It is made up of eleven independent countries namel
  1. Sudan
  2. Ethiopia
  3. Tanzania
  4. Somalia
  5. South Sudan
  6. Kenya
  7. Uganda
  8. Eritrea
  9. Burundi
  10. Rwanda
  11. Djibouti
• Sudan is the largest country in eastern africa
• South Sudan became independent in JULY 2011
• Djibouti is the smallest country in Eastern Africa
• Countries without a coastline are called landlocked e.g
  • B - Burundi
  • U - uganda
  • R - rwanda
  • E - ethiopia
  • S – south sudan

Position And Size of The Countries of Eastern Africa

• Eastern africa lies within latitudes 22 ºN AND 12 ºS and between longitudes 22 ºE and 51 ºE/52 ºE.
  

  COUNTRY	SIZE
  Sudan	1.886 million km²
  Ethiopia	1.104 million km²
  Tanzania	945,087 km²
  Somalia	637,657 km²
  South sudan	644,329 km²
  Kenya	580,367 km²
  Uganda	241,037 km²
  Eritrea	117,600 km²
  Burundi	27,834 km²
  Rwanda	26,338 km²
  Djibouti	23,200 km²

Latitudes And Longitudes

Latitudes

• These are imaginary lines that runs from west to east
• They are also called parallels
• The main line of latitude is equator at 0º
• Equator divides the earth into two equal halves called hemisphere.

Characteristics of latitudes

1. They are parallel
2. They are of different lengths
3. They affect climate
4. They are measured in degrees from the equator
5. They are 180 lines of latitudes in total

Other important lines of latitudes are;

1. The tropic of cancer 231/2 ̊ N
2. The artic circle 66 ½ ̊ N
3. The tropic of capricorn 231/2 S
4. The antartic circle 661/2 ̊ S

Longitudes

• These are imaginary lines that run from north pole to south pole of the earth
• They are also called meridians or horizontals
• Main line of longitude is greenwich meridian at 0 ̊
•  Greenwich meridian is also called prime meridian
• Prime meridian passes through the greenwich town in london and accra in ghana

Characteristics of longitudes

1. They run from north to south
2. They are not parallel
3. They meet at the polesthey affect time
4. They are of the same length
5. They are measured in degrees east por west of prime meridian
6. They are 360 ̊ lines of longitudes in total.

Use of latitude and longitudes to locate places

• They are used to give positions of places on the earth’s surface
• Latitudes locates a place either to the north or south
• Longitudes locates a place either to the west or east

Map interpretation

• A map is a representation of the whole or part of the earth’s surface
• Is a drawing on a flat surface to represent information on the real ground
• Map interpretation is the process of giving meaning to the features shown on a map
• To interpret/understand the map, we must study the main elements namely;frame , key, compass, scale and title

1. Frame - It shows the border line of the area covered by the map
2. Title - It is also called the heading of a map .It shows the name of the area covered by the map
3. Key - It contains the symbol and their meaning. It is the main element of a map
4. Scale - Is the relationship between distances on a map and the actual distances on the ground. Is normally presented as a straight line that is divided into several equal divisions
5. Compass directions - They are used to tell the direction of an object from another on a map

Interpreting human activities

• Human activities include
  1. Keeping livestock
  2. Crop farming
  3. Mining
  4. Trade
  5. Forestry
  6. Tourism
  7. Transpotation
  8. Lumbering
     
     

     Economic activity	Evidence
     Dairy farming	Creameries, dairy farms, cattle dip
     Beef farming	Ranches, slaughter houses
     Cash crop	Tea, coffee,pyrethrum, sisal, cotton
     Mining	Quarry, murram pits, mining company
     Trade	Markets, shops,towns, urban centers
     Lumbering	Saw mills
     Tourism	Game parks/reserves, museum,tourist resorts
     Forestry	Forests
     Fishing	Fish ponds,fishing villages, fish traps, fish processing
     Transportation	Roads,railways,airstrips

 

Interpreting drainage features

• These include rivers,lakes, oceans, dams, boreholes, swamps
• Permanent rivers are shown by a continous blue line
• Seasonal rivers are shown by an identend/broken, blue line.
• Blue colour is used to show waterbodies

Interpreting settlement

• These are people living areas
• They are shown by the use of small black dots
• Settlement patterns include;
• Linear settlement along thr roads, railway lines and rivers
• Nucleted/clustered settlement where people settle at one point in the map

Interpreting administration in the area

• Administrative features include boundaries for location, divisions, districts, county,constituency and world boundaries.presence of offices e.g.chiefs camp, district officer’s offices, disrict commissioner’s office, county commissioner’s office, county governor’s office.

Physical Features

• Are things that occur naturally on the earth’s surface
• They include:
  • Mountains
  • Valleys
  • Plateaus
  • Ocean
  • Seas
  • Gorges
  • Plains
  • Lakes
  • Rivers
  • Swamps
  • Hills, rangers

Relief Physical Features

Mountains

Mountains	Location	Mountains​	Location
Mt.kenya	KENYA	Jabel-marra	SUDAN
Mt.longonot	KENYA	Nubadarfur	SUDAN
Mt.marsabit	KENYA	Jebel Kissu	SUDAN
m.kulal	KENYA	Ras dashan	ETHIOPIA
Menengai crater	KENYA	Mt.meru	TANZANIA
Mt.margaret	KENYA	Guna	ETHIOPIA
Mt.kilimanjaro	TANZANIA	Pare mts	TANZANIA
Danakil alps	ETHIOPIA	Ngorongoro crater	TANZANIA
Moroto	UGANDA	Ruwenzori	UGANDA
Elgon	UGANDA	mfumbiro	UGANDA

 

Plateaus

• Plateaus are the largest relief features in Eastern Africa
  
  

Country	Plateau
KENYA	Uasin gishu, Laikipia, Nyika, Lerochi, Merti, Kinangop
SUDAN	Jabel abyad, Teiga plateau
SOMALIA	Somali
SOMALIA/ ETHIOPIA	ogaden
TANZANIA	Fipa, Central tanzania, Lesongonoi, makonde

Plains

• Are low lying areas of almost flat land

Country	Plain
TANZANIA	Serengeti, maasai
KENYA	Lotikipi, awara, kano, Kaputei, loita, Budalangi,kapiti
UGANDA	Luwero, Nakasongola, Bilesha
SOMALIA	Bilesha, Sarar, Haded

 

Lakes

• A lake is a water body that is surrounded by land
• A hollow/depression filled with water
• We have
  1. Fresh water lakes
  2. Salty water lakes
• Lake victoria is the largest lake in Eastern Africa and second in the world
• Lake Tanganyika is the longest lake in Eastern Africa and second deepest in the world
• Lakes may either be natural or man-made lake.

Country	Lake
ETHIOPIA	Chamo, Abaya, Steffanie, Shala
KENYA	Turkana, Baringo, Bogoria, Nakuru, Elementaita, Naivasha,Magadi, Jipe, Chala, Kenyatta
UGANDA	Albert, Edward, Bunyonyi, Bisini, George, Kyoga, Kivu, mutanda
RWANDA	ruhondo
TANZANIA	Natron, Manyara, eyasi, Rukwa, Malawi, tanganyika

 

Rivers

• A river is a continuous channel of flowing water
• We have permanent and seasonal rivers
• River Nile is the longest river in eastern africa
• Some rivers drain their water into;indian ocean, lake victoria, other lakes, mediterranean sea

Country	River
KENYA	Turkwel, Kerio, Suguta, Ewaso nyiro N,Ewaso nyiro S, Nzoia, Yala, Nyando, Mara,  Migori, Athi, tana
TANZANIA	Pangani, Wami, Rufiji, Matandu, Malagarasi
SOMALIA	Shibeli, juba

 

Swamps

• A swamp is an area covered with soft mud and some vegetation
• Vegetation found in swamps is papyrus reeds

Country	Swamp
KENYA	Lorian, Lotagipi, Yala
TANZANIA	Kilombero, Malagarasi
S.SUDAN	Sudd swamp, Bahr-el-ghazal
UGANDA	kyoga

 

Formation of mountains

• Eastern africa has two types of mountains namely
  • Block mountains
  •  Volcanic mountains

Formation of Block mountains

• They are also called hurst mountains
• They were formed through faulting and uplifting process
• Faults are lines of weakness. Faults were developed as a result of forces acting on the layers of the earth.
• The forces involved are tensional and compressional forces
• The middle block was pushed upward by underground forces
• The underground forces are called upthrust force

Exercise:

Draw the diagram on pg 16 our lives today bk 6

Examples of block mountains

• D – Danakil alps in ethiopia
• A – aberdare ranges in kenya
• M – mau ranges in kenya
• P – pare mountains in tanzania
• U – usambara mountains in tanzania
• R – ruwenzoris mountains in DRC/uganda

Formation of volcanic mountains

• They are also called volcanoes
• They are formed through the process of volcanicity/eruption
• Eruption is when the hot molten material underground is forced out by great pressure
• The hot molten material is called magma
• When magma gets to the surface is called lava
• The magma gets out through a main pipe called vent
• The opening at the top of a volcanic mountain is called a crater
• Most mountains in eastern africa are volcaning mountains
• There are three types of volcanoes namely;
  • Active
  • Dormant
  • Extinct

Examples of volcanic mountains in eastern africa

Country	Volcanic Mountain
TANZANIA	Kilmanjaro, Meru, Ngorongoro, Lool malsin
RWANDA/DRC	nyiragongo
KENYA	Elgon, Longonot, Menengai crater, Marsabit, Suswa, Kulal
UGANDA	Muhavura, mfumbiro
ETHIOPIA	Ras dashan
SUDAN	Jabel el mara

 

Formation of the Rift Valley

• Was formed through the faulting process
• Formed by either tensional or compressional forces
• When two parallel faults developed the tensional forces pullsthe rocks apart
• The middle block between the faults sink
• The steep sides of a rift valley are called escarpments
• Features found on the floor of the firt valley include
  • Volcanic mountains
  • Rivers
  • Fault lakes

Exercise:

Draw diagram on pg 18 our lives today bk 6

Formation of Lakes

• Lakes are huge depressions on the earth’s surface that have filled with water.
• Lakes were formed in different ways namely
  • Earth processes
  • Volcanic processes
  • Erosion processes
  • River action
  • Human made lakes

Earth Movement Processes

1. Fault lakes
2. Downwraping lakes

 

1. Fault lakes
   • They are also called rift valley lakes
   • They were formed through faulting and sinking process
   • They are usually long and have steep side
   • They are usually deep
   • They are found on the floor of the rift valley
   • They include chala, abaya, chamo, stephanie, turkana, baringo, bogoria, nakuru, elemeitaita, naivasha, magdi, natron, eyasi, manyara, rukwa, malawi, tanganyika, kivu, edward,albert.
2. Downwarping lakes
   • Are also called depression lakes
   • They are usually shallow
   • Formed when parts of the earth warped downwards and the sorrounding areas warped upwards They include
     • Vi – victoria
     • Ba - bangweull
     • Cha - chad
     • Kyo - kyoga

Volcanic Processes

1. Crater lakes
2. Lava-dammed lakes

 

1. Crater lakes
   • They are formed when water collects in a volcanic crater
   • They include l.chad, jipe, paradise, shala, kalwe, nyungu,ngozi.
2. Lava-dammed lakes
   • They are formed when lava flow blocks a river valley
   • They include;l.tana, bunyonyi, kivu, mutanda, ruhondo

Erosion process

• They are formed when a moving ice on high mountains erodes the sides of the mountain thus creating depression. Depressions created are called tarns/corriel/cotque
• These lakes are also called glacial lakes
• They include lakes on mountains

Mt Kenya	Gallery tarn, Hanging tarn, Teleki tarn, Nanyuki tarn, Michelson tarn
Ruwenzori mts	Speke tarn, Catherine tarn

River Action

• They are also called deposition lakes or ox-bow lakes
• They are formed in the old stages of a river
• At the stage rivers form numerous mmeanders
• Due to continued erosion and deposition the water cuts off the meander
• They include;
  • Kanyaboli along r.yala
  • Utange along r.rufiji
  • Bilisia along r.tana
  • Shakababo along r.tana
  • Gambi along r. Tana

Human-made lakes

• They are also called artificial lakes
• They are formed when a huge wall is built across rivers
• Water collects behind the wall forming a big artificial lake
• They include;
  • Masinga along r.tana
  • Kiambere along r.tana
  • Kamburu along r.tana
  • Gitaru along r.tana
  • Merowe along r.tana
  • Nalubaale along r.tana

Exercise: Test yourself on pg 20-21 our lives today bk 6

Relief Regions of Eastern Africa

• Relief refers to how high or low an area is from the sea level
• Relief regions are areas where physical features have been grouped according to their height above sea level
• astern africa is divided into five relief regions namely.
  • The coastal plains and lowlands
  • The plateaus
  •  The highlands and mountains
  • The rift valley
  • The lake victoria basin

The coastal plains and lowlands

• Are low-lying strips of land that border
  • The red sea
  • The gulf of aden
  •  The indian ocean
• They lie between 0 – 200m a.s.l
• They are narrow toeards the south
• They are wide towards the north, Widest part in somalia

The plateaus

• They lie between the coastal plains and the highlands
• They lie between 300m-2080m a.s.l
• Are the largest relief regions
• We have
  • Low lying plateau
  • High lying plateau

Low lying plateaus

• They lie between 400m-1000m a.s.l.
• They are immediately after the coastal plains
• This region is also known as the nyika plateau

High lying plateau

• They lie between 1000m-2000m a.s.l.
• Small scattered hills that have resisted erosion are found near inselbergs

Highlands and mountains

• They generally lie above 2000m a.s.l.
• Highlands are densely populated due t
  • Fertile soils
  • Favourable climate
• Mt. Kilimanjaro is the highest mountain at 5895m
• Examples of highlands are;
  • Western highlands of uganda
  • Ethiopian highlands
  • Kenyan highlands
  • North-eastern highlands of tanzania

The Rift Valley

• It was formed through faulting and sinking process
• A valley is a low lying area between two raised grounds
• Begins in jordan in the middle east and ends at beira in mozambique
• In eastern africa the valley is divided into;
  • Ethiopian rift valley
  •  Eastern rift valley
  • Western rift valley

Ethiopian rift valley

• Starts from the red sea and evtends down to l.turkana
• Runs through ethiopia to kenya

Eastern rift valley

• Runs from L.Turkana through Kenya down to Tanzania then North of L.Malawi

Western rift valley

• Runs from north of L.Malawi Tanzania,Uganda,DRC border to L.Albert Lake

Victoria Basin

• It lies between the eastern and western section of the rift valley.
• Was formed through downwarping process
• It lies between 1000m-1500m a.s.l
• Is the source of river nile
• Is densely populated due to
  • Fertile soil
  • Favourable climate i.e.adequate rainfall

Exercise on pg 23-24 our lives today bk 6

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