Globe: Latitudes and Longitudes

A true model (miniature form) of the earth. Globes may be of varying size and type. It shows countries, continents and oceans in their correct size.

A needle is fixed through the globe in a tilted manner, which is called its axis. The real earth has no such needle. It moves around its axis, which is an imaginary line.

Another imaginary line running on the globe divides it into two equal parts. This line is known as the Equator.

All parallel circles from the equator up to the poles are called parallels of latitudes. Latitudes are measured in degrees.

Tropic of Cancer (23 1/2 N), Tropic of Capricorn (23 1/2 S), Arctic Circle (66 1/2 N), Antarctic Circle (66 1/2 S).

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. This area receives the maximum heat.

Areas bounded by the Tropic of Cancer and the Arctic Circle (North) and the Tropic of Capricorn and the Antarctic Circle (South). They have moderate temperatures.

Areas lying between the Arctic Circle and the North Pole, and the Antarctic Circle and the South Pole. It is very cold here because the sun does not rise much above the horizon.

Lines of reference running from the North Pole to the South Pole. The distance between them is measured in 'degrees of longitude'.

The meridian which passed through Greenwich, where the British Royal Observatory is located. Its value is 0 degree longitude.

The earth rotates 360 degrees in about 24 hours. That means 15 degrees an hour or 1 degree in 4 minutes. Places east of Greenwich are ahead of Greenwich time, and those to the west are behind it.

The local time of places which are on different meridians is bound to differ. To maintain uniformity, the local time of some central meridian of a country is taken as the standard time.

82 1/2 degree E (82 degree 30 min E) is treated as the standard meridian. The local time at this meridian is taken as the standard time for the whole country (IST).

The network of the parallels of latitude and meridians of longitude on the globe.

It is not a perfect sphere. It is slightly flattened at the North and South Poles and bulged in the middle (Geoid).

Because the earth is spherical/geoid providing the largest circle at the equator and points at the poles.

Unlike parallel latitudes, longitudes meet at the poles. The distance between them becomes zero at the poles.

The sun acts as the best timekeeper. Local time can be reckoned by the shadow cast by the sun (shortest at noon, longest at sunrise/sunset).

There is a time difference of about 1 hour and 45 minutes in the local times of Dwarka (Gujarat) and Dibrugarh (Assam). Hence IST is essential.

15 * 4 = 60 minutes = 1 hour. It will be 1:00 PM.

Globe is a model of the Earth.

Axis of the earth is tilted.

Equator is 0 degree latitude.

North Pole is 90 degree N.

South Pole is 90 degree S.

All latitudes are parallel circles.

Tropic of Cancer is in the Northern Hemisphere.

Tropic of Capricorn is in the Southern Hemisphere.

Torrid Zone receives maximum heat.

Frigid Zones are covered in ice/snow.

Prime Meridian passes through Greenwich.

Value of Prime Meridian is 0 degree.

There are 360 degrees of longitude.

180 E and 180 W are the same line (International Date Line).

Earth rotates from West to East.

Earth takes 24 hours to complete one rotation.

1 degree longitude = 4 minutes time difference.

15 degrees longitude = 1 hour time difference.

London is on the Prime Meridian.

India lies east of Greenwich at 82 deg 30 min E.

IST is 5 hours 30 minutes ahead of GMT.

Russia has 11 standard times.

The earth is divided into 24 time zones.

Each time zone covers 15 degrees of longitude.

Local time depends on the position of the sun.

Standard time avoids confusion in railway timetables.

Chandrapur (Maharashtra) and Belo Horizonte (Brazil) are on same latitude (20 deg) but opposite hemispheres.

The distance between longitudes decreases towards poles.

Latitudes are unequal in length.

Longitudes are equal in length.

Heat zones depend on the angle of the sun's rays.

Temperate zones have moderate climate.

Midnight sun occurs in Frigid zones (summer).

Grid helps locate any place on earth.

By knowing Latitude and Longitude, we find the exact location.

Equator is the largest latitude.

Antarctic Circle is 66 1/2 S.

Arctic Circle is 66 1/2 N.

Greenwich Mean Time (GMT) is the world standard reference.

Indian Standard Time (IST) applies to the whole nation.

Earth rotates 360 degrees per day.

When it is 7:30 PM in India, it is 2:00 PM in London.

A large country like USA has several time zones.

Local time at Dwarka and Dibrugarh differs by ~1h 45m.

Kabir lives in Bhopal (story in book).

He notes the cricket match starts at 2 pm London time.

This means match starts at 7:30 pm India time.

Longitudes are semi-circles.

Latitudes tell us how far North or South we are.

Longitudes tell us how far East or West we are.

Important coordinates: 23.5 N, 23.5 S, 66.5 N, 66.5 S, 82.5 E (IST)