Introduction of Geography

Lecture :1

Geography:

Geography is the study of locational and spatial variation in natural and human phenomena on Earth.

Vidal de la Blache

Geography is the science of places, concerned with the qualities of potentialities of countries. The particuler character of a country is expressed by the totally of its feature, the social diversities associated with the diversities of places.Geography mainly divided into two parts.

• Physical geography • Human geography

Physical geography:

Physical Geography focuses on geography as an Earth Science.It aims to understand the physical layout of the Earth.

Human geography:

Human Geography is a branch of geography that focuses on the study of patterns and processes that shape human interaction with various environments. It encompasses human, politiclal, cultural, social, and economic aspects. Economic Geography is one of the branch/part of Human Geography.

Economic geography: is the study of the widely varying economic conditions across the earth. The economics of a geographical area can be influenced by climate, geology, and socio-political factors. Geology can affect resource availability, cost of transportation, and land use decisions. Climate can influence natural resource availability (particularly agriculture and forestry products), and working conditions and productivity. The social and political institutions that are unique to a region also have an impact on economic decisions.

Earth Surface

Atmosphere

The atmosphere is the vast gaseous envelope of air that surrounds the Earth. Its boundaries are not easily defined. The atmosphere contains a complex system of gases and suspended particles that behave in many ways like fluids. Many of its constituents are derived from the Earth by way of chemical and biochemical reactions.

Hydrosphere

The hydrosphere describes the waters of the Earth. Water of the hydrosphere exists in three states: liquid, solid and gaseous (water vapor). Water occurs in two general chemical conditions, fresh and salty. Water exists on the Earth in various stores, including the: atmosphere, oceans, lakes, rivers, glaciers, snowfields and groundwater. Water moves from one store to another by way of: evaporation, condensation, precipitation, deposition, runoff, infiltration, sublimation, transpiration, and groundwater flow.

Lithosphere

Is the solid inorganic portion of the Earth (composed of rocks, minerals, and elements). It consists with crust and a portion of the upper mantle.

Biosphere

Zone of the Earth where life is found. The biosphere consists of all living things, plant and animal. This zone is characterized by life in profusion, diversity, and ingenious complexity. Cycling of matter in this sphere involves not only metabolic reactions in organisms, but also many abiotic chemical reactions. Also called Ecosphere.

|Earth's Atmosphere | |
|The Earth is surrounded by a blanket of air, which we call the atmosphere. It reaches over 560 kilometers (348 miles) | |
|from the surface of the Earth, so we are only able to see what occurs fairly close to the ground. Early attempts at | |
|studying the nature of the atmosphere used clues from the weather, the beautiful multi-colored sunsets and sunrises, and| |
|the twinkling of stars. With the use of sensitive instruments from space, we are able to get a better view of the | |
|functioning of our atmosphere. | |
|Life on Earth is supported by the atmosphere, solar energy, and our planet's magnetic fields. The atmosphere absorbs the| |
|energy from the Sun, recycles water and other chemicals, and works with the electrical and magnetic forces to provide a | |
|moderate climate. The atmosphere also protects us from high-energy radiation and the frigid vacuum of space. | |
|The envelope of gas surrounding the Earth changes from the ground up. Four distinct layers have been identified using | |
|thermal characteristics (temperature changes), chemical composition, movement, and density. | |
|Troposphere | |
|The troposphere starts at the Earth's surface and extends 8 to 14.5 kilometers high (5 to 9 miles). This part of the | |
|atmosphere is the most dense. As you climb higher in this layer, the temperature drops from about 17 to -52 degrees | |
|Celsius. Almost all weather is in this region. The tropopause separates the troposphere from the next layer. The | |
|tropopause and the troposphere are known as the lower atmosphere. | |
|Stratosphere | |
|The stratosphere starts just above the troposphere and extends to 50 kilometers (31 miles) high. Compared to the | |
|troposphere, this part of the atmosphere is dry and less dense. The temperature in this region increases gradually to -3| |
|degrees Celsius, due to the absorbtion of ultraviolet radiation. The ozone layer, which absorbs and scatters the solar | |
|ultraviolet radiation, is in this layer. Ninety-nine percent of "air" is located in the troposphere and stratosphere. | |
|The stratopause separates the stratosphere from the next layer. | |
|Mesosphere | |
|The mesosphere starts just above the stratosphere and extends to 85 kilometers (53 miles) high. In this region, the | |
|temperatures again fall as low as -93 degrees Celsius as you increase in altitude. The chemicals are in an excited | |
|state, as they absorb energy from the Sun. The mesopause separates the mesophere from the thermosphere. | |
|The regions of the stratosphere and the mesosphere, along with the stratopause and mesopause, are called the middle | |
|atmosphere by scientists. This area has been closely studied on the ATLAS Spacelab mission series. | |
|Thermosphere | |
|The thermosphere starts just above the mesosphere and extends to 600 kilometers (372 miles) high. The temperatures go up| |
|as you increase in altitude due to the Sun's energy. Temperatures in this region can go as high as 1,727 degrees | |
|Celsius. Chemical reactions occur much faster here than on the surface of the Earth. This layer is known as the upper | |
|atmosphere. | |
|The upper and lower layers of the thermosphere will be studied more closely during the Tethered Satellite Mission | |
|(TSS-1R). | |
|Composition of the Atmosphere | |
|The atmosphere is primarily composed of Nitrogen (N2, 78%), Oxygen (O2, 21%), and Argon (Ar, 1%). A myriad of other very| |
|influential components are also present which include the water (H2O, 0 - 7%), "greenhouse" gases or Ozone (O, 0 - 0.01%), Carbon Dioxide (CO2, 0.01-0.1%), | |
|Beyond the Atmosphere | |
|The exosphere starts at the top to the thermosphere and continues until it merges with interplanetary gases, or space. | |
|In this region of the atmosphere, Hydrogen and Helium are the prime components and are only present at extremely low | |
|densities. | |

Relatively thin life-supporting stratum of the Earth's surface, extending from a few kilometres into the atmosphere to the deep-sea vents of the ocean. The biosphere is a global ecosystem composed of living organisms (biota) and the abiotic (nonliving) factors from which they derive energy and nutrients.