Write a short note on the term Latitude

Latitude is a measure of the angular distance of a given point from the north and south of the equator. It is measured in degrees from the equator towards either pole. One degree is divided into sixty equal parts and each unit is called a minute (’). A minute is further divided into sixty equal parts and each unit is called a second (”). The value of each latitude is followed by the word North or South. This is generally indicated by the letter ‘N’ o ‘S’. There are 90 lines of latitude from 0^o to 90^o N and another 90 lines of latitude from 0^o to 90^oS. So in all there are 180 lines of latitude, all drawn in East-West direction, parallel to the equator.

As the latitudes are parallel to each other, the distance between two latitudes remain the same all around the earth

The equator is the largest possible latitude. As the earth is a sphere, they reduce in length, so that 90^o N and 90^oS are represented by mere points.

Some Important Latitudes

Apart from 0^o latitude, there are some other important latitudes. The ancient Greeks studied them and have them special names. The 23 1/2^o N latitude is called the tropic of Cancer, while tropic of Capricorn is 23 1/2^o S latitude. They have been specially fixed, because the direct rays of the sun are experienced only in the zone between these two latitudes. So the direct rays of the sun ‘move’ over all the latitudes between 23 1/2^o N and 23 1/2^o twice a year, but never over any latitude beyond this zone.

Heat Zones

The latitudes help us to divide the earth into different Heat Zones, which are as follows :

1. The Torrid Zone lies between the tropic of Cancer and tropic of Capricorn (23 1/2^oN to 23 1/2^oS). As the sun’s rays fall vertically throughout the year, this zone receives maximum heat.

2. The Temperate Zone lies between the tropic of cancer and Arctic Circle in the northern hemisphere (23 1/2^oN to 66 1/2^oN) and between the tropic of Capricorn and Antractic Circle in the southern hemisphere (23 1/2^oS to 66 1/2^oS). This zone has moderate temperature as the angle of the sun’s rays goes on decreasing pole wards. It is neither very hot in summer nor very cold in winter.

The Frigid Zone lies between the Arctic Circle and North Pole in the northern hemisphere and between the Antractic Circle and South Pole in the southern hemisphere. The rays of the sun fall in a great slant on this zone and the sun does not rise much above the horizon. It is extremely cold here all the year and even more severely cold in winter.