Page 112 - Social Studies 7

Longitude

Longitude is an angular distance of the earth drawn in the east or the west of the
prime meridian. Vertical lines are drawn in this angular distance. These vertical
lines are called lines of longitude. They are imaginary lines drawn to determine
the time of a place. There are meridians of longitude, 180° to the east and 180° to
the west of the prime meridian.
The prime meridian is an imaginary line drawn vertically from the North Pole to
South Pole at 0° longitude. It divides the earth into the eastern hemisphere and
the western hemisphere. It runs through Greenwich, England.

The earth rotates one degree longitude in every four minutes.
1° = 4 minutes

15° = 1 hour

The point in which 180° of the eastern hemisphere and 180° of the western
hemisphere meet, such lines are called International Date Line (IDL). It is drawn
zigzag to minimize the complication seen in time in the same territory.
Uses of Latitudes and Longitudes

latitude longitude
• To find the distance of a place in • To find the distance of a place
the south or north from the equator in the east and west from the
• To know the climate of a place prime meridian
• To calculate the length of day and • To find the local time of a place
night • To determine the world time
• To find the distance of a place standard time and local time
[1° latitude= 111 km] The standard time of Nepal is
measured from Gauri Shankar
• To divide their earth into three Himal, it is located at 86°15'
climate zones-tropical, Temperate east longitude.
and Frizids

Key Words

angular distance : the angular separation between two objects
frizid : freezed, covered with snow

Dynamic Social Studies and Population Education - Book VII 112