Page 112 - SST Class 06

The Earth tilts at an angle of 23½°. If it did not tilt, also means that 21 June is the shortest day and
the length of days and nights would be equal. But 22 December is the longest day in the Southern
due to this tilt, the days and nights are not of Hemisphere.
equal length. q The exact time that the Earth takes in one

The vertical line from the The earth’s axis rotation is 23 hours, 56 minutes and 4.091
earth’s orbital plane
N.P.
seconds and is considered to be equal to 24
hours for all practical purposes. In the same
way, the Earth takes 365 days, 5 hours, 48
23½ ° T o of C minutes and 45.51 seconds to complete one
r p c i
revolution round the Sun.
ancer
66½°
The plane SUN
of the
earth’s orbit
Quiz Time
Equator
Tr
f a r orn Fill in the blanks :
opic o C p ic
1. The Earth rotates on its ___________ like a top.
S.P. 2. The Earth makes an angle of 66½° with its
Phenomenon of day and night on the earth ___________ plane.
Experiment 3. The spinning of the Earth on its axis is called
___________ .
Light a torch at a globe. You will find that only
one pole is in light while the other remains in the 4. The Earth tilts at an angle of ___________ .
dark. Now, rotate the globe. You will find that the 5. The two motions of the Earth are ___________
area shifts from light to dark and dark to light, but and ___________ .
the pole in light continues to face light, while the
pole in dark continues to be in dark. It follows
that some areas on the Earth receive light for a REVOLUTION
longer duration than other areas. The Earth also goes round the Sun and this motion

is called revolution . The path that the Earth travels
is fixed and is called its orbit. This orbit is
Day Day Night Night elongated like an egg and is called the ellipse .

Due to this elongated path, the distance between
the Earth and the Sun varies. When the Earth is
nearest to the Sun, it is called perihelion and
when it is farthest, it is called aphelion .

Day Day Night Night

PERIHELION APHELION
146 million km 151 million km

Globe facing the torch

Info Bits
Info Bits
Ear th ’s o b r it
q 21 June is the longest day while 22 December is Earth’s orbit
the shortest day in the Northern Hemisphere. It
Contemporary Social Science-6
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