Seasons & Time
Earth s Movements Rotation Movement of Earth Around the Sun Elliptical Orbit Revolution 24 Hours (1 Day) 365 Days (1 Year)
The Earth s Revolution & the Tilt of the axis cause variations in the amount of Sunshine
Variations in the amount of Sunshine are the basis of Seasons
Seasonal Change Recurrence of Winter, Summer and the Rainy Season one after the other on the Earth
Perihelion & Aphelion
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.
Earth Takes 365 Days 5 Hours 365 ¼ Days 48 Minutes 45 Seconds to complete one Revolution
Leap Year Year 2016 Total Days Balance 2017 365 Days 6 Hours 2018 365 Days 6 Hours 2019 365 Days 6 Hours 2020 365 Days 6 Hours 2020 will have 366 Days Once in 4 Year with 366 Days 1 Day 29 Days in February
23 ½ 0 66 ½ 0 Parallelism of Axis Orbital Plane The Earth has an Inclination & it maintains the Tilt throughout its Revolution
Apparent Movement of Sun
March 21 & Sep 23
March 21 & Sep 23
Equinoxes Sun over Equator on Mar 21 & Sep 23 Equal Sunlight in both Hemisphere Equal Day & Night In Northern Hemisphere from Mar Sep
Summer Solstice Sun over Tropic of Cancer on June 21 Longest Day Northern Hemisphere Longest Night Southern Hemisphere
Winter Solstice Sun over Tropic of Capricorn on Dec 22 Longest Night Northern Hemisphere Longest Day Southern Hemisphere In Southern Hemisphere from Sep Mar
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 23 ----------------- Equator Equal Day & Night Dec 22 Winter Solstice ------------------- Long Night in N Hem.
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.
Spring Transition from Winter to Summer March, April Summer Months (N.H.)
Autumn Transition from Summer towards Winter Atmospheric Temperature Decreases Short Day & Lengthy Night Trees Shed their Leaves N. Hem. Oct, Nov
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
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
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
Traditional Seasons of India Vasantha Mar, April Greeshma May, June Varsha Sarat Hemanta Sisira July, Aug Sep, Oct Nov, Dec Jan, Feb
Time Calculation Ancient Period Based on the Apex Position of the Sun & Length of Shadow Later Time Calculation became Scientific
Earth's Rotation - Facts West East Sun Rises 1 st in East 24 Hours to Complete 1 Rotation W E
W E Sun Rises at First in Arunachal Pradesh
Angular Distance of Earth = 360 0 To Complete 360 0 Rotation = 24 hours [ 24 x 60 = 1440 Minutes ] To Complete 360 0 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) ]
am pm 11.52 11.56 12 12.4 12.8 am pm 9.00 10.00 11.00 12 1.00 2.00 3.00 2 0 1 0 0 1 0 2 0 W E 45 0 30 0 15 0 0 15 0 30 0 45 0 W E
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
Global Time Zones
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
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
Activity 3 (Complete the Table)
180 0 165 0 150 0 135 0 0 90 0 75 0 60 0 45 0 30 0 15 0 0 0 15 0 30 0 45 0 60 0 75 0 90 0 105 0 120 0 135 0 150 0 165 0 180 0 120 105 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
Sunday 180 0 0 0 Monday International Date Line At 180 0 Longitude East & West there is 24 Hours Difference Same place with 24 Hours difference
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
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.
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
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
Additional Activities 1. 2. 3. 4. 5.
Michael Angelo M.A. MA (Phi.,His.) HSA(Social Science) St. Mary s H.S. Palliport mamichaelma@gmail.com 9746953695