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Seasons
&
Time
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Earth’s Movements
Rotation Revolution
24 Hours (1 Day) 365 Days (1 Year)
Movement
of Earth
Around the
Sun
Elliptical
Orbit
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The Earth’s Revolution & the Tilt of
the axis
cause variations in the amount of
Sunshine
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Variations
in the
amount of
Sunshine
are the
basis of
Seasons
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Recurrence of
Winter, Summer
and the Rainy
Season one after
the other on the
Earth
Seasonal Change
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Perihelion & Aphelion
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Activity 1 (Short Notes)
1. How much time does the Earth take to
complete One Revolution?
2. What is a Leap Year?
3. Difference between Rotation & Revolution
4.
5.
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Earth Takes
365 Days
5 Hours
48 Minutes
45 Seconds
to complete
one
Revolution
365 ¼
Days
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Year Total Days Balance
2016
2017 365 Days 6 Hours
2018 365 Days 6 Hours
2019 365 Days 6 Hours
2020 365 Days 6 Hours
1 Day
2020 will have 366 Days
29 Days
in
February
Leap Year Once in 4 Year with 366 Days
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66 ½0
23 ½0
Orbital Plane
Parallelism of Axis
The Earth has an Inclination & it maintains
the Tilt throughout its Revolution
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Apparent
Movement of
Sun
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March 21 & Sep 23
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March 21 & Sep 23
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Equinoxes
Sun over Equator
on Mar 21 & Sep 23
Equal Sunlight
in both Hemisphere
Equal Day & Night
In Northern
Hemisphere
from Mar –
Sep
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Summer Solstice
Sun over Tropic of
Cancer on June 21
Longest Day
Northern Hemisphere
Longest Night
Southern Hemisphere
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Winter Solstice
Sun over Tropic of
Capricorn on Dec 22
Longest Night
Northern Hemisphere
Longest Day
Southern Hemisphere
In Southern
Hemisphere
from Sep –
Mar
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Date Name Position of
Sun
Result
---------------- Equinox Equator Equal Day &
Night
June 21 Summer
Solstice
------------------- Long Day in N
Hem.
Sep 23 ----------------- Equator Equal Day &
Night
Dec 22 Winter
Solstice
------------------- Long Night in N
Hem.
Activity 2 (Complete the Table)
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Date Name Position
of Sun
Result
Mar 21 Equinox Equator Equal Day
& Night
June 21 Summer
Solstice
Tropic of
Cancer
Long Day in
N Hem.
Sep 23 Equinox Equator Equal Day
& Night
Dec 22 Winter
Solstice
Tropic of
Capricorn
Long Night
in N Hem.
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Spring
Transition from Winter to Summer
March, April Summer Months (N.H.)
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Autumn
Transition from Summer
towards Winter
Atmospheric Temperature
Decreases
Short Day & Lengthy Night
Trees Shed their Leaves
N. Hem. Oct, Nov
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Months
Movement of
Sun
Seasons
NH SH
Mar 21 -
June 21
Equator
Tropic of Cancer
Spring Autumn
June 21-
Sep 23
Tropic of Cancer
Equator
Summer Winter
Sep 23 -
Dec 22
Equator
Tropic of Capricorn
Autumn Spring
Dec 22 –
Mar 21
Tropic of Capricorn
Equator
Winter Summer
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Mid Latitude Region
o Seasonal Differences
are Deep
o At Tropic of Capricorn
Longer Days &
Shorter Nights (S.H.)
o At Tropic of Cancer
Continuous Day light in
Arctic Circle for 6 Months
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Equatorial Region
o Some Difference
in the Length of
Day & Night
o Hot Climate
throughout Year
o Not much
Seasonal Change
Polar Region
o Much Difference
in the Length of
Day & Night
o Summer
Cooler & Shorter
o Winter
Severe & Longer
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Traditional Seasons of India
Vasantha Mar, April
Greeshma May, June
Varsha July, Aug
Sarat Sep, Oct
Hemanta Nov, Dec
Sisira Jan, Feb
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Based on the
Apex Position of
the Sun
&
Length of Shadow
Time Calculation – Ancient Period
Later Time Calculation became Scientific
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West East
Sun Rises 1st
in East
24 Hours to Complete
1 Rotation
Earth's Rotation - Facts
W
E
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Sun Rises at
First in
Arunachal
Pradesh
W E
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Angular Distance of Earth = 3600
To Complete 3600
Rotation = 24 hours
[ 24 x 60 = 1440 Minutes ]
To Complete 3600
Rotation = 1440 Min.
To Complete 10
Rotation = 4 Min.
[ 1440 / 360 = 4 Minutes ]
To Complete 150
Rotation = 1 hour
[ 15 x 4 = 60 Min. (1 hour) ]
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20
10
0 10
20
11.52 11.56 12 12.4 12.8
am pm
W E
450
300
150
0 150
300
450
9.00 10.00 11.00 12 1.00 2.00 3.00
am pm
W E
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00 Longitude
Place of British Royal
Observatory
Worldwide Time
Calculation based on it
Prime Meridian
World in to 24 Time Zones
Greenwich Line
Each with 1
Hour Difference
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Global Time Zones
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Each Longitude has
Different Time
A country may have
Different Longitude
A country may have
Different Time
So
Longitude Passes thru Middle of
the Country is set as
Standard Meridian & Time
Standard Time
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Indian Standard
Time (IST)
Longitudinal Extent
= 680E – 97
0E
82 ½ 0E Passes
thru Middle of the
Country
82 ½ 0E is the
Standard Meridian
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Activity 3 (Complete the Table)
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180
0
165
0
150
0
135
0 0120
105
0
90
0
75
0
60
0
45
0
30
0
15
0
00
15
0
30
0
45
0
60
0
75
0
90
0
105
0
120
0
135
0
150
0
165
0
180
0
10 11 12
S
u
n
d
a
y
1 2 3 4 5 6 7 8 9 10
A
m
M
o
n
d
a y
11 12
n
o
o
n
1
p
m
2 3 4 5 6 7 8 9 10
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Sunday
Monday
1800
00
International Date Line
At 1800
Longitude
East & West
there is 24 Hours
Difference
Same place with
24 Hours difference
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International Date Line
Avoided Land
Area
Thru Pacific
Ocean
It is an
Imaginary Line
Travelers who cross this from East Add 1 Day &
from West Deduct 1 Day
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Activity 4 (Globe Observation)
Observe the Globe and :
1. Find out the International Date Line
2. Identify the Continents situated to the West &
East of this Line
3. Which Travelers of these Continents will gain
one Day on crossing International Date Line
4.
5.
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Asia &
Australia
West East
N America
&
S America
Those who cross this Line and go to
N&S America will gain One Day
In
te
rn
atio
nal D
ate
L
in
e
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Activity 5 (Time Calculation)
What will be the time in New York (740
W) when it is noon at Greenwich
Longitudnal Difference between New York &
Greenwich = 740
Time for 10
Longitude = 4 Minuts
Time for 740
Longitude = 4 x 74 = 296 Min.
= 4 Hours 56 Min.
As New York is in West = Greenwich Time –
Time Difference
= 12 – 4 H 56 M
= 7.04 am
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Additional Activities
1.
2.
3.
4.
5.
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Michael Angelo M.A. MA (Phi.,His.)
HSA(Social Science)
St. Mary’s H.S. [email protected]
9746953695
