SS 1 Geography (1st Term)

MAJOR LANDFORMS OF THE WORLD

MOUNTAINS Mountains are great elevated land surfaces resulting from intense action of internal forces. They have steep slopes and show distinct peaks. Mountains are classified according to their mode of formation, resulting in four major types of mountains. These are (i) Fold mountains (ii) Block Mountains (iii) Volcanic Mountains and (iv) Residual mountain (a) Fold Mountains Characteristics: They contain old hard rocks with steep sides. They have wrinkling or folding appearance and show distinct peaks of great heights. Fold Mountains exist in layered form. They are soft, and have anticlines and synclines. Folding shortens the earth’s crust. They form most wide spread type of Mountains and are noted for active volcanoes. They form the highest Mountain ranges. Examples of Fold Mountains include Himalayas, Rockies, Andes Alps and Atlas Mountains Mode of formation: They are formed by large- scale horizontal earth movement as a result of stress and compressional… Read More »MAJOR LANDFORMS OF THE WORLD

GEOGRAPHIC INFORMATION SYSTEM (GIS)

A geographic information system (GIS) is a system designed to capture, store, manipulate, analyze, manage, and present all types of spatial or geographical data. The acronym GIS is sometimes used for Geographical Information Science or Geospatial Information Studies to refer to the academic discipline or career of working with geographic information systems and is a large domain within the broader academic discipline of Geoinformatics. In general, GIS describes any information system that integrates, stores, edits, analyzes, shares, and displays geographic information. GIS applications are tools that allow users to create interactive queries (user-created searches), analyze spatial information, edit data in maps, and present the results of all these operations. Geographic information science is the science underlying geographic concepts, applications, and systems. Data representation GIS data represents real objects (such as roads, land use, elevation, trees, waterways, etc.). Real objects can be divided into two abstractions: discrete objects (e.g., a house) and continuous fields (such as rainfall amount, or elevations). Traditionally, there are two… Read More »GEOGRAPHIC INFORMATION SYSTEM (GIS)

ROCKS OF THE EARTH

The earth crust consists of rocks. A rock is any mineral material of the earth. It may be a combination of different mineral element such as silica which contains silicon and oxygen. All the rocks differ from one another in texture, structure, colour, permeability, mode of occurrence and degree of resistance to denudation. Types of rocks: Rocks are classified into the following; Igneous rocks, Sedimentary rocks and Metamorphic rocks. Characteristics of Igneous rocks They are crystalline in structure ie they contain crystals. They do not occur in layers. They do not contain fossils. They are usually hard and impervious. They are resistant to erosion and element of weather. Mode of Formation They are formed by the cooling and solidification of molten magma, ejected from beneath the earth crust. As the magma moves towards the surface, it comes in contact with lower temperature, hence cooling and solidifying to form… Read More »ROCKS OF THE EARTH

INTERNAL STRUCTURE OF THE EARTH

The internal structure of the earth is made up of three concentric layers which are (a) The crust (Lithosphere) (b) The mantle (Mesosphere) (c) The core (Barysphere) The Crust This is subdivided into upper and lower crust. The upper crust consists of granite rocks and forms the continent. The main minerals here are silica and aluminium, collectively referred to as SIAL. It has an average density of 2.7 EVALUATION QUESTIONS Mention the 3 concentric layers of the internal layer of the earth. SIAl is a combination of—– and —–minerals The lower part of the earth crust consists of basalt rocks and forms the ocean floor. It contains minerals like silica, iron and magnesium, collectively referred to as SIMA. It has an average density of 3.0 The Mantle This zone is found just beneath the crust. It is about 290km thick with a density of 3.3 Its main… Read More »INTERNAL STRUCTURE OF THE EARTH

STRUCTURE OF THE EARTH

The structure of the earth is grouped into two zones: The outer structure and the internal structure. THE OUTER STRUCTURE OF THE EARTH The outer structure of the earth is made up of four zones or layers: Lithosphere Hydrosphere Atmosphere Biosphere Lithosphere: This is the solid portion of the earth. It is the outermost zone of the earth which is made up of rocks and mineral materials. It represents 30% of the earth surface. Importance: It forms the basis for all human settlement. All mineral resources are derived here. It aids transportation through construction of roads, railways, airports, etc. It aids farming activities. Most human activities like mining, trading, etc are done here. Hydrosphere: This refers to the liquid portion of the earth. It includes the oceans, sea, rivers, streams and springs, lakes, etc. It covers 70% of the earth’s crust. Importance: Provides water for domestic uses. Provides medium… Read More »STRUCTURE OF THE EARTH

CALCULATION OF DISTANCES AND LOCAL TIME

Calculation of distance using lines of latitude Procedures: locate the two places involved find the latitude difference between the two places Note: North-North= subtract North-South= add South-North= add Equator-North= add or subtract Equator-South= add or subtract multiply the latitude difference by 111km 1°=111km( 1° of latitude is approx. 111km on land) Example 1 Calculate the distance between S.Africa(30oS) and Spain(40oN) Solution: i) Lat.diff.=30oS+40N=70o since 1o=111km therefore, 111×70=7770km The distance b/w S.Africa and Spain=7,7770km EVALUATION QUESTIONS What is the distance between place A (lat.20oS) and place B (lat.51oN)? What is the distance between the Equator and Lagos (14oN)? Calculation of Local Time using the lines of longitude Procedures: locate the places involved find longitude difference conversion to time adjust time according to the direction of movement(west or east) Examples: If the time at town A(long.75°W) is 5.00pm on Friday, what will be the time and day… Read More »CALCULATION OF DISTANCES AND LOCAL TIME

LATITUDE & LONGITUDE

MEANING OF LATITUDE Latitude is an angular distance of a point on earth’s surface measured in degrees from the centre of the earth. Latitude is parallel to the equator .Equator divides the earth into two equal halves known as Northern & southern hemisphere. Lines of latitude are sometimes called parallel of latitude. IMPORTANT LINES OF LATITUDE The equator 0° (ii) North pole 90°N (iii) South pole 90°S (iv) The tropic of Cancer 23 1/2°N (v) Tropic of Capricorn 23 1/2°S (vi) Arctic circle 66 1/2°N (vii) Antarctic circle 66 1/2°S . USES OF LINES OF LATITUDES The lines of latitude are used to determine the exact location of a place on the atlas map. They are used to calculate the distance between two places on the earth surface. LONGITUDE Longitude is an angular distance measured in degree east and west of the Greenwich Meridian. It is an… Read More »LATITUDE & LONGITUDE

EARTH AS A PLANET

The shape of the earth The earth has a spherical shape. Its shape can also be described as GEOID. Though we walk on “flat” surface, it is almost like a sphere and it is slightly flattened at the two poles. There are many facts to prove that the earth is spherical. Size of the Earth The earth is the fifth largest planet in the solar system. The surface area of the earth is approximately 443 million square kilometers (197 million square miles). The earth has a polar diameter of about 12,722km and equatorial diameter of about 12,762km. At the equator, the earth measures about 40,085km in circumference. The polar circumference is 39,955km. Its mean density is estimated to be 5.5 gram per cubic centimeters. EVALUATION QUESTIONS The shape of the earth is _____? Describe the size of the earth. PROOFS OF THE EARTH’S SPHERICITY Circumnavigation of the Earth:… Read More »EARTH AS A PLANET

THE SOLAR SYSTEM

Solar system is the description of the position of the earth and other planets in relation to the sun. The solar system comprises of the sun and the nine planets. All the planets revolve round the sun in “elliptical orbits”. The Universe The universe is made up of many heavenly bodies, group of stars form clusters which are known as galaxies or nebulas. Our local groups or galaxy i.e the earth galaxy is known as ‘The Milky Way’. It contains twenty seven galaxies. A satellite is a smaller body which moves round a planet. The moon is the natural satellite of the earth. Below is a summary of the components of the Solar System Planets Number of satellites Distance from sun in Km Years it takes to complete revolution Mercury None 57,600,000 88 days Venus None 107,200,000 225 days Earth One 148,800,000 365 days Mars Two 227,200,000 687… Read More »THE SOLAR SYSTEM

INTRODUCTION TO GEOGRAPHY

INTRODUCTION TO GEOGRAPHY: MEANING, SCOPE AND VALUE MEANING OF GEOGRAPHY The word Geography is derived from the Greek word ‘Geo’ meaning the earth, and ‘graph’ which means description. Geography can therefore be defined as the description of the earth. However, Geography does not only describe the surface of the earth and its features. It also investigates the inter-relationship between man and his environment. Hence Geography can also be referred to as the study of people, their activities, places and physical things within the earth. Geography deals with the study of different people in different locations of the earth including their activities like agriculture, mining, trading, fishing, manufacturing, construction, etc. Geography also relates with the different peoples of the world, their occupations, cultures, ways of dressing, religion, etc In addition, Geography involves the study of physical things within the earth such as rocks, mountains, plains, valleys, rivers, oceans, weather, rainfall,… Read More »INTRODUCTION TO GEOGRAPHY

SS 1 Geography (1st Term)

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