Seasons & Time.

Transcription

1 Seasons & Time

2 Earth s Movements Rotation Movement of Earth Around the Sun Elliptical Orbit Revolution 24 Hours (1 Day) 365 Days (1 Year)

3 The Earth s Revolution & the Tilt of the axis cause variations in the amount of Sunshine

4 Variations in the amount of Sunshine are the basis of Seasons

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6 Seasonal Change Recurrence of Winter, Summer and the Rainy Season one after the other on the Earth

7 Perihelion & Aphelion

8 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.

9 Earth Takes 365 Days 5 Hours 365 ¼ Days 48 Minutes 45 Seconds to complete one Revolution

10 Leap Year Year 2016 Total Days Balance Days 6 Hours Days 6 Hours Days 6 Hours Days 6 Hours 2020 will have 366 Days Once in 4 Year with 366 Days 1 Day 29 Days in February

11 23 ½ 0 66 ½ 0 Parallelism of Axis Orbital Plane The Earth has an Inclination & it maintains the Tilt throughout its Revolution

12 Apparent Movement of Sun

13 March 21 & Sep 23

14 March 21 & Sep 23

15 Equinoxes Sun over Equator on Mar 21 & Sep 23 Equal Sunlight in both Hemisphere Equal Day & Night In Northern Hemisphere from Mar Sep

16 Summer Solstice Sun over Tropic of Cancer on June 21 Longest Day Northern Hemisphere Longest Night Southern Hemisphere

17 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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19 Activity 2 (Complete the Table) Date Name Position of Sun Result Equinox Equator Equal Day & Night June 21 Summer Solstice Long Day in N Hem. Sep Equator Equal Day & Night Dec 22 Winter Solstice Long Night in N Hem.

20 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.

21 Spring Transition from Winter to Summer March, April Summer Months (N.H.)

22 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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24 Months Movement of Sun Seasons NH SH Mar 21 - June 21 Equator Tropic of Cancer Spring Autumn June 21- Tropic of Cancer Summer Winter Sep 23 Equator Sep 23 - Dec 22 Equator Tropic of Capricorn Autumn Spring Dec 22 Tropic of Capricorn Winter Summer Mar 21 Equator

25 Mid Latitude Region o Seasonal Differences are Deep o At Tropic of Capricorn o Longer Days & Shorter Nights (S.H.) At Tropic of Cancer Continuous Day light in Arctic Circle for 6 Months

26 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

27 Traditional Seasons of India Vasantha Mar, April Greeshma May, June Varsha Sarat Hemanta Sisira July, Aug Sep, Oct Nov, Dec Jan, Feb

28 Time Calculation Ancient Period Based on the Apex Position of the Sun & Length of Shadow Later Time Calculation became Scientific

29 Earth's Rotation - Facts West East Sun Rises 1 st in East 24 Hours to Complete 1 Rotation W E

30 W E Sun Rises at First in Arunachal Pradesh

31 Angular Distance of Earth = To Complete Rotation = 24 hours [ 24 x 60 = 1440 Minutes ] To Complete Rotation = 1440 Min. To Complete 1 0 Rotation = 4 Min. [ 1440 / 360 = 4 Minutes ] To Complete 15 0 Rotation = 1 hour [ 15 x 4 = 60 Min. (1 hour) ]

32 am pm am pm W E W E

33 Greenwich Line 0 0 Longitude Place of British Royal Observatory Worldwide Time Calculation based on it Prime Meridian World in to 24 Time Zones Each with 1 Hour Difference

34 Global Time Zones

35 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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37 Indian Standard Time (IST) Longitudinal Extent = 68 0 E 97 0 E 82 ½ 0 E Passes thru Middle of the Country 82 ½ 0 E is the Standard Meridian

38 Activity 3 (Complete the Table)

39 S u n d a y A m M o n d a y n o o n 1 p m

40 Sunday Monday International Date Line At Longitude East & West there is 24 Hours Difference Same place with 24 Hours difference

41 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

42 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.

43 International Date Line West East Asia & Australia N America & S America Those who cross this N&S America will Line and go to gain One Day

44 Activity 5 (Time Calculation) What will be the time in New York (74 0 W) when it is noon at Greenwich Longitudnal Difference between New York & Greenwich = 74 0 Time for 1 0 Longitude Time for 74 0 Longitude = 4 Minuts = 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

45 Additional Activities

46 Michael Angelo M.A. MA (Phi.,His.) HSA(Social Science) St. Mary s H.S. Palliport mamichaelma@gmail.com