The Globe - A Model of the Earth
What does globe mean?
THE GLOBE
Our earth like all other heavenly bodies is spherical in shape. People in the past believed it to be flat. The photographs taken from space proved that the earth is spherical in shape. It resembles, an orange, slightly flattened at the poles and bulging at the equator. This particular shape of the earth is called 'geoid'.
The shape of the earth can be best represented on a model so that we can study it properly. This model is called the globe.
CONTINENTS AND OCEANS
If you look at the globe, you will find that most parts are painted blue which represent oceans. There are four major oceans. The Pacific ocean, the Atlantic ocean, the Indian ocean and the Arctic ocean. Some geographers identify another ocean named as the Southern ocean or the Antarctic ocean, while others believe it to be an extension of the three oceans, viz. The Pacific, the Atlantic and the Indian ocean. The Pacific ocean is the largest ocean, while the Atlantic is the busiest ocean.
You will also find major areas painted yellow or brown. These denote continents. There are seven continents, e.g. Asia, Europe, Africa, North America, South America, Australia and Antarctica.
Asia is the largest and Australia is the smallest continent.
You will also notice some vertical and horizontal lines on the globe. Besides, there are these fixed points on the top and bottom of the globe. These fixed points are the North Pole and the South Pole.
The imaginary line exactly in the middle of the two poles is called the Equator. The equator divides the globe into two hemispheres- the Northern Hemisphere and the Southern Hemisphere. It runs round the circumference of the globe.
PARALLELS OF LATITUDES
You will see full circles on the globe running parallel to the equator in east-west direction. These circles are called Parallels of Latitude. The equator represents the 0° latitude. It is measured in degrees. Each hemis-phere has 90° latitude in the Northern Hemisphere is called the North Pole, while the 90° latitude in the Southern Hemisphere is called the South Pole.
Besides the equator, there are some other important latitudes:
The Tropic of Cancer is 23 1/2°݇ N.
The Tropic of Capricorn is 23 1/2°݇ S.
The Arctic Circle is 66 1/2°݇ S.
The Antarctic Circle is 66 1/2°݇ S.
The above latitudes help in dividing the earth into various climatic zones.
For the sake of convenience, the parallels of latitude are drawn at an interval of 10°.
the equator is the biggest of all latitudes. The length of latitudes decreases as we move away from the equator to the poles.
MERIDIANS OF LONGITUDES
You will find some vertical lines on the globe. In fact these are semi-circles joining the two poles. These semicircles cut all the parallels of latitudes. These semicircles are called Meridians of Longitudes. The zero degree meridian passes through the Greenwich laboratory near London (U.K.). It is called Prime Meridiar. There are 180 longitudes in western half and another 180 longitudes in the eastern half of the globe. Thus, there are 360 semi-circles running between the poles. Meridians to the east of Greenwich are marked 'E' and those to the west are marked 'W'.
On the globe, you will find a network of latitudes and longitudes called the Grid Latitudes and longitudes cut each-other at right angles. The grid helps us in locating places. For example, Pondicherry lies at 12° N and 80° E. We can find the exact location of Pondicherry with the help of latitudes and longitudes.
After Reading this chapter you will be able to answer below questions:
1. What is a globe?
2. What is a continent?
3. Name the major oceans.
4. What is a grid? How can we locate a place on the globe with the help of the grid?
5. What is the importance of the Prime (Greenwich) meridian?
On the globe given below mark and lebel the following:
1. Lines of latitude
2. Lines of Longitude
3. North Pole
4. Equator
5. Prime meridian
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