The document explains the geoid shape of the Earth, its rotation, and the significance of poles, with the north pointed towards the pole star and the south as the opposite end. It covers the concepts of latitude and longitude, including the division of the Earth into different zones such as frigid, temperate, and torrid, and the establishment of time zones based on meridians. Additionally, it discusses the Greenwich Mean Time (GMT) and the International Date Line, emphasizing the need for standard time to avoid discrepancies across different regions.

1. Prepared By: Navya Rai
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2.  The term used to describe the shape of the
Earth is geoid, meaning ‘Earth Shaped’.
 Earth rotates on its own axis.
 The end points of the axis of the Earth are
called poles.
 The pole which points
towards the Pole Star is
called North Pole.
 The opposite end is called
South Pole
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3.  The globe is used as a true representation of
the Earth because it is modelled after the
shape of the Earth.
The first globe
was made by
Martin Behaim in
1492
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4.  The Earth’s surface is vast. To find places
imaginary lines called latitudes and
longitudes are drawn on a globe.
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5.  Latitude is the angular distance between the
Equator and any place north or south of it.
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6.  There are four important parallels of latitude:
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7.  Different places on the Earth receive different
amount of sunlight.
 The Sun’s rays are concentrated in the areas
near the Equator.
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8.  Frigid zone is lies between the Arctic Circle
and the North Pole in the Northern
Hemisphere and the Antarctic Circle and the
South Pole in the Southern Hemisphere.
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9.  The Temperate Zone is located between the
Tropic of Cancer and the Arctic Circle in the
Northern Hemisphere.
 And the Tropic of Capricorn and the Antarctic
circle in Southern Hemisphere.
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‘Temperate’ means
‘moderate’. These area
experiences mild and
moderate climate.

10.  The regions lying between the Tropic of
Cancer and the Tropic of Capricorn get the
midday Sun overhead at least once in a year.
This region known as Torrid Zone or Tropical
Zone.
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11.  Longitude is the
measurement east or west
of the prime meridian.
 Longitude is measured by
imaginary lines that run
around the Earth vertically
(up and down) and meet at
the North and South Poles.
These lines are known
as meridians.
 Each meridian measures
one arcdegree of longitude.
The distance around the
Earth measures 360 degrees.
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12.  The meridian that runs through Greenwich,
England, is internationally accepted as the
line of 0 degrees longitude, or prime
meridian. The ante meridian is halfway
around the world, at 180 degrees. It is the
basis for the International Date Line.
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13.  A pattern of crossed lines formed by lines of
latitudes and longitudes are called global
grid.
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14.  The Earth moves at a constant rate, covering
360° of arc in 24 hours. The following
relationships exists between time and arc:
 Time Arc
 24 hours 360°
 1 hour 15°
 4 minutes 1°
 The Earth rotates
west to East.
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15.  The Earth completes the rotation of 360
degree in one day or 24 hours.
 It rotates 15 degree in one hour or 1 degree in
4 minutes.
 The Earth rotates west to east, so for every 15
degree we go eastwards, the time is advanced
by 1 hour.
 Thus, it can be concluded that places east of
Greenwich see the Sun earlier and are ahead
in time.
 The 24 hours period of a day divided into two
time periods- 12 hours before noon (a.m) and
12 hours after noon (p.m)
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16.  If we know the Greenwich Mean Time
(GMT) we can find out the local time of an
area by adding or subtracting the difference
in time from the GMT.
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17.  If each place determines its
time on the basis of its
meridian, there will be
much difference in local
time from one town to the
other.
 In order avoid such
situations and confusion
standard time is followed
by most countries. The
countries decide their
standard time based on
their central meridian
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18.  The Indian
Government
has accepted
the meridian 82
1/2o E, which
passes through
Mirzapur near
Allahabad in
Uttar Pradesh,
as Indian
Standard Time.
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19.  The International Date Line,
established in 1884, passes
through the mid-Pacific
Ocean and roughly follows
a 180 degrees longitude
north-south line on the
Earth.
 It is located halfway round
the world from the prime
meridian—the zero degrees
longitude established in
Greenwich, England, in
1852.
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20. Navya Rai