Class 6 𝐆𝐋𝐎𝐁𝐄

### 𝐈𝐧𝐭𝐫𝐨𝐝𝐮𝐜𝐭𝐢𝐨𝐧 𝐨𝐟 𝐆𝐥𝐨𝐛𝐞

color{green}(•) It is slightly flattened at the North and the South Poles and bulge in the middle.

color{green}(•) Can you imagine how it looks? You may look at a globe carefully in your classroom to get an idea.

color{green}(•) Globe is a true model (miniature form) of the earth (Figure 2.1).

color{green}(•) Globes may be of varying size and type – big ones, which cannot be carried easily, small pocket globes, and globe-like balloons, which can be inflated and are handy and carried with ease.

color{green}(•) The globe is not fixed. It can be rotated the same way as a top spin or a potter’s wheel is rotated.

color{green}(•) On the globe, countries, continents and oceans are shown in their correct size.

color{green}(•) It is difficult to describe the location of a point on a sphere like the earth.

color{green}(•) Now the question arises as to how to locate a place on it? We need certain points of reference and lines to find out the location of places.

color{green}(•) You will notice that a needle is fixed through the globe in a tilted manner, which is called its color{red}("𝐚𝐱𝐢𝐬").

color{green}(•) Two points on the globe through which the needle passes are two poles – North Pole and South Pole.

color{green}(•) The globe can be moved around this needle from west to east just as the earth moves.

color{green}(•) But, remember there is a major difference.

color{green}(•) The real earth has no such needle.

color{green}(•) It moves around its axis, which is an imaginary line.

color{green}(•) Another imaginary line running on the globe divides it into two equal parts.

color{green}(•) This line is known as the color{red}("𝐞𝐪𝐮𝐚𝐭𝐨𝐫.")

color{green}(•) The northern half of the earth is known as the Northern Hemisphere and the southern half is known as the Southern Hemisphere.

color{green}(•) They are both equal halves.

color{green}(•) Therefore, the equator is an imaginary circular line and is a very important reference point to locate places on the earth.

color{green}(•) All parallel circles from the equator up to the poles are called color{red}("𝐩𝐚𝐫𝐚𝐥𝐥𝐞𝐥𝐬 𝐨𝐟 𝐥𝐚𝐭𝐢𝐭𝐮𝐝𝐞𝐬.")

color{green}(•) Latitudes are measured in degrees.

color{green}(•) The equator represents the zero degree latitude.

color{green}(•) Since the distance from the equator to either of the poles is one-fourth of a circle round the earth, it will measure
¼th of 360 degrees, i.e. 90°.

color{green}(•) Thus, 90 degrees north latitude marks the North Pole and 90 degrees south latitude marks the South Pole.

color{green}(•) As such, all parallels north of the equator are called ‘north latitudes.’

color{green}(•) Similarly all parallels south of the equator are called ‘south latitudes.’

color{green}(•) The value of each latitude is, therefore, followed by either the word north or south.

color{green}(•) Generally, this is indicated by the letter ‘N’ or ‘S’.

color{green}(•) For example, both Chandrapur in Maharashtra (India) and Belo Horizonte in Brazil (South America) are located on
parallels of about 20° latitude.

color{green}(•) But the former is 20° north of the equator and the latter is 20° south of it.

color{green}(•) We, therefore, say that Chandrapur is situated at 20° N latitude and Belo Horizonte is situated at 20° S latitude.

color{green}(•) We see in Figure 2.2 that as we move away from the equator, the size of the parallels of latitude decreases.

### 𝐈𝐌𝐏𝐎𝐑𝐓𝐀𝐍𝐓 𝐏𝐀𝐑𝐀𝐋𝐋𝐄𝐋𝐒 𝐎𝐅 𝐋𝐀𝐓𝐈𝐓𝐔𝐃𝐄𝐒

color{green}(•) Besides the equator (0°), the North Pole (90°N) and the South Pole (90° S), there are four important parallels of latitudes–

(𝐢) 𝐓𝐫𝐨𝐩𝐢𝐜 𝐨𝐟 𝐂𝐚𝐧𝐜𝐞𝐫 (23½° N) in the Northern Hemisphere.

(𝐢𝐢) 𝐓𝐫𝐨𝐩𝐢𝐜 𝐨𝐟 𝐂𝐚𝐩𝐫𝐢𝐜𝐨𝐫𝐧 (23½° S) in the Southern Hemisphere.

(𝐢𝐢𝐢) 𝐀𝐫𝐜𝐭𝐢𝐜 𝐂𝐢𝐫𝐜𝐥𝐞 at 66½° north of the equator.

(𝐢𝐯) 𝐀𝐧𝐭𝐚𝐫𝐜𝐭𝐢𝐜 𝐂𝐢𝐫𝐜𝐥𝐞 at 66½° south of the equator.

### 𝐇𝐄𝐀𝐓 𝐙𝐎𝐍𝐄𝐒 𝐎𝐅 𝐓𝐇𝐄 𝐄𝐀𝐑𝐓𝐇

color{green}(•) The mid-day sun is exactly overhead at least once a year on all latitudes in between the Tropic of Cancer and the Tropic of Capricorn.

color{green}(•) This area, therefore, receives the maximum heat and is called the color{red}("𝐓𝐨𝐫𝐫𝐢𝐝 𝐙𝐨𝐧𝐞.")

color{green}(•) The mid-day sun never shines overhead on any latitude beyond the Tropic of Cancer and the Tropic of Capricorn.

color{green}(•) The angle of the sun’s rays goes on decreasing towards the poles.

color{green}(•) As such, the areas bounded by the Tropic of Cancer and the Arctic Circle in the Northern Hemisphere, and the Tropic of Capricorn and the Antarctic Circle in the Southern Hemisphere, have moderate temperatures.

color{green}(•) These are, therefore, called color{red}("𝐓𝐞𝐦𝐩𝐞𝐫𝐚𝐭𝐞 𝐙𝐨𝐧𝐞𝐬.")

color{green}(•) Areas lying between the Arctic Circle and the North Pole in the Northern Hemisphere and the Antarctic Circle and
the South Pole in the Southern Hemisphere, are very cold.

color{green}(•) It is because here the sun does not rise much above the horizon.

color{green}(•) Therefore, its rays are always slanting and provide less heat.

color{green}(•) These are, therefore, called color{red}("𝐅𝐫𝐢𝐠𝐢𝐝 𝐙𝐨𝐧𝐞𝐬") (very cold).