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- 1. CLASS VIII GEOGRAPHY <ul><li>BR. HECTOR PINTO </li></ul><ul><li>INFANT JESUS HIGH SCHOOL </li></ul>
- 2. Natural Environments: The Atmosphere GE 101 – Spring 2007 Boston University Myneni Lecture 03: Rotating Sphere Jan-22-07 (2 of 15) Earth as Rotating Sphere <ul><li>Let us begin to lay the foundation for the first part of the course, which is - </li></ul><ul><li>Energy balance of the earth system </li></ul><ul><li>that is, What energy comes in, how it changes form, what goes out </li></ul><ul><li>The energy source for the earth is the sun. Therefore, we need to look at the earth-sun </li></ul><ul><li>“ astronomical relationship ” </li></ul><ul><li>We begin by looking at the earth as a Rotating, Orbiting Sphere </li></ul><ul><li>From this we will be able to answer many questions about the basic climate of the earth </li></ul><ul><li>- Why are there seasons? </li></ul><ul><li>- Why is there such a temperature difference between the equator and poles? </li></ul><ul><li>- What effect does this temperature difference have on the circulation of the </li></ul><ul><li>atmosphere and oceans </li></ul>
- 3. Earth and Moon Presented by Br. Hector Pinto INFANT JESUS SCHOOL, CHALLAKERE
- 4. SHAPE OF THE EARTH <ul><li>Many speculations about the shape of the earth </li></ul><ul><li>Babylonians thought- earth was circular in shape & surrounded by river Okeanos </li></ul><ul><li>Anaximander regarded –earth as cylindrical body. </li></ul><ul><li>Ancient Indians – earth was flat with a huge mountain in the middle. </li></ul><ul><li>Pythogoras, Eratosthenes, Arya Bhatta & Ptlolemy – earth spherical in shape </li></ul>Earth is geoid in shape
- 5. Nicolaus Copernicus <ul><li>The Earth moves, in two ways. </li></ul><ul><li>It rotates on an axis (period = 1 day). </li></ul><ul><li>It revolves around the sun (period = 1 year) in same direction. </li></ul>
- 6. The Copernican Model
- 7. <ul><li>Now – not a perfect sphere. </li></ul><ul><li>Flattened at the poles & bulging at the equator </li></ul><ul><li>Named ‘geoid’. </li></ul>
- 8. Our Planets At A Glance <ul><li> Earth </li></ul>The Earth is the third closest planet to the sun and the fifth largest planet. It is small and rocky and as far as we know, the only planet that has life on it. About three quarters of the Earth's surface is covered with water and it is the only planet on which water can exist in liquid form on the surface. This is the reason that life can be sustained on it. The Earth is about 4.5 - 4.6 billion years old. It is orbited by one moon.
- 9. Apollo 17 view of earth
- 10. The Earth: <ul><li>Only planet which has a biosphere </li></ul><ul><li>-is an oblated sphere, </li></ul><ul><li>-rotates on its imaginary </li></ul><ul><li>axis counterclockwise every </li></ul><ul><li>24 hours or 1 day, </li></ul><ul><li>-appears blue in space </li></ul><ul><li>because it is 70% water, </li></ul>
- 11. Earth is unique:- <ul><li>Has an atmosphere which is rich in oxygen (21%) and nitrogen (77%) </li></ul><ul><li>* presence of oxygen has made life possible on earth. </li></ul><ul><li>* acts as protective blanket around the earth. </li></ul><ul><li>* Ozone layer in the atmosphere absorbs the harmful ultraviolet radiation from the Sun & prevents it from reaching the earth. </li></ul><ul><li>* atmosphere absorbs terrestrial radiation & keeps earth warm during nights and winter. </li></ul><ul><li>* presence of atmosphere reduces extremes of temperature. </li></ul>
- 12. We breathe: <ul><li>78% nitrogen </li></ul><ul><li>21% oxygen </li></ul><ul><li>1% argon, neon, carbon dioxide, neon, & krypton </li></ul>
- 13. <ul><li>2. Has abundance of water – 70% of earth’s surface covered by ocean and seas. </li></ul><ul><li>* called watery planet </li></ul><ul><li>* layer of water is called hydrosphere. </li></ul><ul><li>* water is present in solid and liquid. </li></ul><ul><li>* water appears in gaseous state in the atmosphere also. </li></ul><ul><li>* water is essential for supporting plants, animals and other life forms on earth. </li></ul><ul><li>* water in oceans helps to moderate the temperature conditions on earth which makes the circulation of water possible. </li></ul>
- 14. <ul><li>Layer of rocks which form the surface of the earth is called LITHOSPHERE. </li></ul><ul><li>Lithosphere provides valuable soil layer which sustains all plant life which supports the greenhouse effect </li></ul><ul><li>Plants in turn support directly or indirectly all forms of life on earth </li></ul><ul><li>Also provides all mineral resources needed by us </li></ul>
- 15. <ul><li>The combination of favourable physical environment has made Earth a HABITABLE PLANET. </li></ul><ul><li>Variety & abundance of plants, animals and other forms of life make Earth unique planet. </li></ul><ul><li>No life in other planets </li></ul>
- 16. <ul><li>Various forms of life on earth constitute the BIOSPHERE </li></ul><ul><li>Earth has provided an environment for the evolution of human beings and the progress of human civilization </li></ul>
- 17. How did life begin? <ul><li>It is thought that life began when lightning hit the sea. </li></ul><ul><li>Lightening sent energy into the water. </li></ul><ul><li>Chemicals in the sea were mixed together by energy. </li></ul><ul><li>New substances called amino acids were made from which life was able to grow. </li></ul>
- 18. AMAZING! <ul><li>The first living things on earth were so small you could fit thousands of them on the head of a pin. </li></ul>
- 19. What were the first living things?
- 20. BACTERIA. <ul><li>They lived in the sea. Some bacteria changed into alage, which were simple plants. Alage lived in the sea in masses, like huge blankets. </li></ul><ul><li>They made oxygen which helped to turn the sky and sea blue. </li></ul>
- 21. ANTIPODAL BALANCE BETWEEN LAND AND WATER <ul><li>There is an anipodal balance of land and water directly opposite sides of the Earth. </li></ul><ul><li>Land on one side of the globe is balanced by water on the other side of the earth. For instance, the North Polar Arctic Ocean is opposite the Antarctic continent. </li></ul><ul><li>Northern Hemisphere is girdled by the land masses of the North America and Eurasia and Southern Hemisphere are the continents of South America, Africa and Australia </li></ul><ul><li>The landmass of Antarctica has three prominent protruding areas – one towards South America, another towards South Africa and a third towards Australia </li></ul>
- 22. SHAPE OF THE EARTH <ul><li>In old days, earth was considered to be a flat disc with steep edges. </li></ul><ul><li>All heavenly bodies revolved around the Earth. </li></ul><ul><li>Aryabhatta , famous Indian astronomer, believed Earth was spherical in shape and rotated on its axis. </li></ul><ul><li>In Europe, Greek philosopher Pythagoras and Aristotle were first to state that Earth was spherical in shape. Considerable opposition to this view. </li></ul><ul><li>Now we have convincing evidence from man’s landing on the Moon that the Earth is spherical in shape, the evolution of this idea may be considered briefly. </li></ul>
- 23. Proofs for shape <ul><li>LUNAR ECLIPSE:The earth casts a shadow on the moon during a lunar eclipse. This shadow is always semi-circular in shape </li></ul>
- 24. <ul><li>SUNRISE AND SUNSET: The fact that the time of sunrise varies from place to place on the Earth proves that the Earth is not a flat disc. </li></ul><ul><li>If the earth was flat, all places on the earth would have sunrise and sunset at the same time. </li></ul>
- 25. Circumnavigation <ul><li>If we travel around the earth without changing the direction, we arrive at the place we started from. </li></ul><ul><li>As the earth is spherical in shape, it is possible to circumnavigate the earth. </li></ul><ul><li>Magellan’s crew was first to go round the earth in a ship and complete the voyage without encountering a sharp edge. </li></ul><ul><li>Now aircrafts make many trips round the world on scheduled flights. </li></ul>
- 26. <ul><li>SIGHTING A SHIP: </li></ul><ul><li>When a ship approaches the shore, a person standing on the shore can see the smoke at first and then the chimney and then the ship as a whole. </li></ul>
- 27. ARTIFICIAL SATELLITES <ul><li>The photographs of the earth & other planets sent by the artificial satellites prove that the earth is round. </li></ul><ul><li>Aerial photographs from space show earth spherical. Astronauts have taken pictures of earth from moon showing its spherical shape. </li></ul>
- 28. SHAPE OF THE EARTH <ul><li>Now – not a perfect sphere. </li></ul><ul><li>Flattened at the poles & bulging at the equator </li></ul><ul><li>Named ‘geoid’. </li></ul><ul><li>At equator diameter measures 12,756 km </li></ul><ul><li>Poles the diameter is 12,714 k.m. giving a difference of 42km. </li></ul>Earth is geoid in shape
- 29. ) <ul><li>We begin by looking at the earth as a Rotating, Orbiting Sphere </li></ul>12756 km 12714 km N S <ul><ul><li>Approximately spherical </li></ul></ul><ul><ul><li>Actually an “oblate ellipsoid” </li></ul></ul><ul><ul><li>Slightly compressed from north to south </li></ul></ul><ul><ul><li>Slightly bulging from east to west </li></ul></ul><ul><ul><li>- But, we treat it as a sphere </li></ul></ul>Shape of the Earth The Blue Marble
- 30. SIZE OF THE EARTH <ul><li>Average diameter is about 12,735 km. </li></ul><ul><li>Four planets – Mercury, Venus, Mars and Pluto (?) are smaller than the Earth. </li></ul><ul><li>Others are larger </li></ul><ul><li>Early attempt made to estimate the size in 3 rd century BC by Greek philosopher called Eratosthanes. </li></ul>
- 31. Comparison between moon and earth
- 32. Earth’s Moon <ul><li>Only natural satellite- avge distance from Earth is 3,84,000km. </li></ul><ul><li>Its diameter is 3470 km </li></ul><ul><li>Moons duration of one rotation is apprx 29 days 5 hours, usually calculated as 29 days </li></ul><ul><li>Revolution around the earth takes approx 27 days and 3 hours- counted as 27 days </li></ul><ul><li>The moon’s surface is covered in dust and rocky debris from meteor impacts. It has no water or atmosphere. The dark areas of the moon are called maria (Maria is a Latin word meaning “seas”). Maria are large craters which have been filled by solidified lava. </li></ul>
- 33. Full moon <ul><li>The moon reflects light from the sun onto the earth’s surface. Sometimes the moon may appear reddish-brown in color as the sunlight is deflected through dust in the earth’s atmosphere. </li></ul><ul><li>The moon’s gravitational effects on the earth are most apparent in the “coming” and “going” of the tides </li></ul>
- 34. Moon <ul><li>Appears so large because it is so close to earth but diameter is quarter of the Earth’s diameter </li></ul><ul><li>Experiences extreme of temperature- no atmosphere- its day temperature is 134degree C and night temperature is about -170 C duing two week long lunar night </li></ul><ul><li>Since no atmosphere, no weather conditions </li></ul>
- 35. Surface of the Moon <ul><li>Many craters have been detected on surface </li></ul><ul><li>Some of the mountain ranges like Leibnitz near the Moon’s south pole has a height of 10670 m-higher than Mount Everest </li></ul>
- 37. <ul><li>Who was the first person to land on the Moon? </li></ul><ul><li>NEIL ARMSTRONG </li></ul><ul><li>Which Year? </li></ul><ul><li>21 st July, 1969 </li></ul>
- 40. Footprint of an astronaut on the surface of the moon <ul><li>Erosion takes place at very slow rate because of lack of rain and wind. </li></ul><ul><li>Footprints will not disappear for many; yeas. </li></ul>
- 41. Apollo 16's Lunar Roving Vehicle parked at the side of the bowl-shaped, 40 metres wide, Plum crater
- 42. Mars in comparison with Earth Relatively small planet, half the size of the earth
- 43. I bet you know the answers! <ul><li>What causes day & night? </li></ul><ul><li>Which one is bigger the earth or the moon? </li></ul><ul><li>Where does the moon get its light from? </li></ul><ul><li>What percent of the earth is always lit by the sun? </li></ul><ul><li>How many stars are in our solar system? </li></ul><ul><li>How many days does it take for the Earth to revolve around the sun? </li></ul><ul><li>How many low and high tides on Earth every 24 hours? </li></ul>
- 44. <ul><li>Outline </li></ul><ul><li>the Moon is a bit of an oddball </li></ul><ul><li>formation of the moon, a rough start </li></ul><ul><li>Earth’s climate </li></ul><ul><li>precession - the Earth as a spinning top </li></ul><ul><li>the Moon and stability of Earth’s climate </li></ul>
- 45. Where does the moon get its light?
- 46. It actually gets its light from the sun. How Does it do that? Just like a mirror.
- 47. PHASES OF THE MOON
- 48. <ul><li>Phases of the Moon </li></ul>
- 49. GLOSSARY <ul><li>Orbit - The path of the Moon around the Earth. </li></ul><ul><li>Rotate - The Earth spins around, like a top, about its axis once each day. Waning - Shrinking. </li></ul><ul><li>Waxing - Growing </li></ul><ul><li>Gibbous - Swollen on one side </li></ul><ul><li> </li></ul>
- 50. What causes the phases of the Moon?
- 52. The phases of the moon are caused by the relative positions of the earth, sun, and moon. The moon goes around the earth, on average, in 27 days 7 hours 43 minutes.
- 53. MOON PHASES <ul><li>As the moon circles the Earth, the shape of the moon appears to change; this is because different amounts of the illuminated part of the moon are facing us. The shape varies from a full moon (when the Earth is between the sun and the moon) to a new moon (when the moon is between the sun and the Earth). </li></ul>
- 63. Oooh! Aaah!
- 64. New Moon
- 66. Waxing Crescent
- 68. First Quarter
- 70. Waxing Gibbous
- 72. Full Moon
- 75. Waning Gibbous
- 77. Last Quarter
- 79. Waning crescent
- 81. Full Moon <ul><li>A full moon appears as an entire circle in the sky </li></ul>
- 82. Quarter Moon/Half Moon <ul><li>A half moon looks like half a circle. It is sometimes called a quarter moon </li></ul>
- 83. Crescent Moon <ul><li>A crescent moon is part way between a half moon and a new moon, or between a new moon and a half moon. </li></ul>
- 84. New Moon <ul><li>The new moon is the phase of the moon when the moon is not visible from Earth, because the side of the moon that is facing us is not being lit by the sun. </li></ul>
- 85. Phases of the Moon Remember the ‘right hand rule’ for orbits.
- 86. Sun, Earth, and Moon <ul><li>Lunar Phases </li></ul><ul><li>Eclipses </li></ul><ul><li>Tides </li></ul><ul><li>Celestial Motion </li></ul>
- 87. Phases of the Moon <ul><li>The appearance or shape of the Moon gradually changes through the course of a month. This cycle - the cycle of lunar phases, may be explained if we state the following: </li></ul><ul><li>The Moon is spherical in shape. </li></ul><ul><li>The Moon is not self-luminous, but rather reflects the light of the distant Sun. </li></ul><ul><li>The Moon circles the Earth once per month. </li></ul>
- 89. As the Moon Changes NSF North Mississippi GK-8
- 90. <ul><li>The Moon is not a light source, it does not make its own light. The moon reflects light from the sun. We can see the Moon because light from the Sun bounces off it back to the Earth . If the Sun wasn't there, we wouldn't be able to see it. </li></ul><ul><li>The Sun always lights up (illuminates) half of the Moon at one time. </li></ul><ul><li>The Moon appears to change shape but what we are actually seeing is the Moon lit up by the light from the Sun in different ways on different days </li></ul>
- 91. <ul><li>The image on the right shows you what you would see if you looked at the moon tonight . If it is black then it's a new moon. </li></ul>
- 92. Why does the moon have phases? <ul><li>The revolution of the Moon around the Earth causes the Moon to appear to have phases. </li></ul>NSF North Mississippi GK-8
- 93. 8 Phases of the Moon <ul><li>New Moon </li></ul><ul><li>Waxing Crescent </li></ul><ul><li>First Quarter or Half Moon </li></ul><ul><li>Waxing Gibbous </li></ul><ul><li>Full Moon </li></ul><ul><li>Waning Gibbous </li></ul><ul><li>Last Quarter or Half Moon </li></ul><ul><li>Waning Crescent </li></ul>NSF North Mississippi GK-8
- 94. New Moon <ul><li>The moon is not visible from Earth. The moon is between the Sun and the Earth. </li></ul><ul><li>The dark side is facing us. </li></ul><ul><li>This phase lasts one night. </li></ul>NSF North Mississippi GK-8
- 95. Waxing Crescent <ul><li>Waxing means that the bright side is increasing. The right side is the bright side. </li></ul><ul><li>Less than one half of the moon is illuminated. </li></ul><ul><li>This phase includes any visible moon from a small sliver to almost half. </li></ul>NSF North Mississippi GK-8
- 96. First Quarter or Half Moon <ul><li>The entire right side of the moon is illuminated. </li></ul><ul><li>The moon looks like a half circle. </li></ul><ul><li>The illuminated side is increasing. </li></ul><ul><li>This phase only lasts one night. </li></ul>NSF North Mississippi GK-8
- 97. Waxing Gibbous <ul><li>Gibbous means that more than one half is visible, but it is not quite full. </li></ul><ul><li>This phase includes the night after the first quarter to the night before the full moon. </li></ul>NSF North Mississippi GK-8
- 98. Full Moon <ul><li>The moon is full and bright. It looks like a large circle. </li></ul><ul><li>The illuminated side is facing us. </li></ul><ul><li>Only happens one night per lunation. </li></ul>NSF North Mississippi GK-8
- 99. Waning Gibbous <ul><li>The moon appears more than half but not quite full. </li></ul><ul><li>Waning means that the illuminated side is decreasing. </li></ul><ul><li>The left side is the bright side. </li></ul>NSF North Mississippi GK-8
- 100. Last Quarter or Half Moon <ul><li>Left Half of the moon is illuminated. </li></ul><ul><li>The illuminated side is decreasing. </li></ul><ul><li>This phase also only lasts for one night. </li></ul>NSF North Mississippi GK-8
- 101. Waning Crescent <ul><li>Less than one half of the moon is illuminated. </li></ul><ul><li>The moon will continue to become smaller and smaller. </li></ul>NSF North Mississippi GK-8
- 102. NSF North Mississippi GK-8
- 103. : Phases and Shadows Experiment
- 104. Questions??? <ul><li>(ending) New Moon </li></ul><ul><li>Full Moon </li></ul><ul><li>Waxing Gibbous Moon </li></ul><ul><li>Waning (decreasing) Gibbous Moon </li></ul><ul><li>Waxing (increasing) Crescent Moon </li></ul><ul><li>Half Moon </li></ul><ul><li>Waning Crescent Moon </li></ul><ul><li>Half Moon </li></ul><ul><li>(for beginning) New Moon </li></ul>
- 105. <ul><li>1 (for beginning) New Moon </li></ul><ul><li>2 Waxing (increasing) Crescent Moon </li></ul><ul><li>3 Half Moon </li></ul><ul><li>4 Waxing Gibbous Moon </li></ul><ul><li>5 Full Moon </li></ul><ul><li>6 Waning (decreasing) Gibbous Moon 7 Half Moon </li></ul><ul><li>8 Waning Crescent Moon </li></ul><ul><li>9 (ending) New Moon </li></ul>
- 106. Which of the following is a true statement. <ul><li> a. A waning moon is increasing in size. b. A waxing moon is increasing in size. c. A waxing moon is decreasing in size. d. Waxing and waning mean the same. e. All of the answers are true. f. All of the answers are false. </li></ul>
- 107. When the moon is seen from the Earth as a whole circle, it is called a- <ul><ul><li>A Crescent moon </li></ul></ul><ul><ul><li>B Full moon </li></ul></ul><ul><ul><li>C Half moon </li></ul></ul><ul><ul><li>D New moon </li></ul></ul>
- 108. When the moon is seen from the Earth as a whole circle, it is called a FULL MOON.
- 109. Which of these is the next phase of the moon? <ul><li>New Moon --- Waxing Crescent --- ? </li></ul><ul><li>F Full Moon </li></ul><ul><li>G Waning Crescent </li></ul><ul><li>H First Quarter </li></ul><ul><li>J Waxing Gibbous </li></ul>
- 110. The next major phase of the moon would be… <ul><li>First quarter. </li></ul><ul><li>Just think about it…the </li></ul><ul><li>New moon (can only get bigger. Or = Waxing).. </li></ul><ul><li>Then comes Waxing crescent …next is </li></ul><ul><li>First quarter …then </li></ul><ul><li>Waxing Gibbous and then a </li></ul><ul><li>Full Moon . </li></ul>
- 111. <ul><li>The waning phase of the Moon occurs between _______________. </li></ul><ul><li>New Moon and Full Moon </li></ul><ul><li>Full Moon and New Moon </li></ul><ul><li>First Quarter and Third Quarter </li></ul><ul><li>Third Quarter and First Quarter </li></ul>
- 112. <ul><li>b. Full Moon and New Moon </li></ul>
- 113. Did you know? <ul><li>Why is only one side of the moon visible from the earth? </li></ul><ul><li>We always see the same side of the moon. The Moon always keeps the same side pointing towards us so we can never see the 'back' of the Moon from the Earth. </li></ul>
- 114. <ul><li>The moon revolves or orbits the Earth once every 29 days. </li></ul><ul><li>We all ways see the same side of the moon because the moon rotates and revolves at about the same speed. </li></ul><ul><li>The opposite side of the moon is hidden from our view </li></ul>
- 115. The Phases of the Moon <ul><li>Students arrange tactile moon phase cards in a sequence that makes sense, </li></ul><ul><li>identify the names of the moon phases, </li></ul><ul><li>and learn where the moon is at each phase. </li></ul>
- 116. Fun Facts for Lunatics <ul><ul><ul><li>Lunar Libration: The spin of the Moon proceeds at a uniform rate while the orbit is at a slightly nonuniform rate. The spin can get a little bit ahead or behind the orbit. Hence the face of the Moon presented to the Earth rocks back and forth by some 6° each month, a phenomenon known as longitudinal libration. </li></ul></ul></ul><ul><ul><ul><li>The Moon's orbital plane: The plane of the Moon's orbit is tilted by 5° with respect to that of the Earth's orbit. Hence the rotation axis of the Earth is tilted with respect to the Moon's orbital plane by an amount within 5° of 23.5°, depending on whether the two tilts are in or out of phase. The length of time between moonrise and moonset for, say, a full Moon varies with the season as well. (Also, note the phasing between the two tilts varies continually with time, going full circle every 18.6 years.) </li></ul></ul></ul><ul><ul><ul><li>The variable speed of the Moon: Like the Earth, the Moon moves in a slightly elliptical orbit as well. Hence, while the average time elapsed from, say, New Moon to First Quarter is 7.4 days, the actual time can be as short as 6.7 days near perigee (closest approach to Earth) or as long as 8.1 days near apogee. </li></ul></ul></ul>
- 117. Moon at Perigee and Apogee <ul><ul><li>Distance: 359,861 km </li></ul></ul><ul><ul><li>Distance: 405,948 km </li></ul></ul>
- 118. When this photo was taken by the crew of Apollo 8, was the Moon waxing or waning as seen from Earth? North Pole
- 119. Eclipses <ul><li>Celestial bodies are always “eclipsing” or moving in front of each other. </li></ul><ul><li>Eclipses occur at predictable intervals. </li></ul><ul><li>Other names include: Transits and Occultations. </li></ul><ul><li>Solar Eclipses can be total, partial, or annular </li></ul>
- 122. Moon's shadow on Earth taken by French cosmonaut Jean-Pierre Haigneré aboard the Mir
- 125. Lunar eclipse How Does the moon change its phase? Experiment
- 132. "Here lie the bodies of Ho and Hi, Whose fate, though sad, is risible; Being slain because they could not spy Th' eclipse which was invisible." Author unknown: Said to refer to the Chinese eclipse of 2136 BC or 2159 BC. "On the day of the new moon, in the month of Hiyar, the Sun was put to shame, and went down in the daytime, with Mars in attendance." One of the earliest written records of an eclipse of the Sun, on 3 May 1375 BC, found in the city of Ugarit in Mesopotamia.(Reprinted, from Chasing the Shadow , copyright 1994 by Joel K Harris and Richard L Talcott , by permission of Kalmbach Publishing Co. "If the Sun at its rising is like a crescent and wears a crown like the Moon: the king wll capture his enemy's land; evil will leave the land, and (the land) will experience good . . . " Refers to a solar eclipse of 27 May 669 BC. Rasil the older, Babylonian scribe to the king. Quoted in Historical Eclipses and Earth's Rotation , by F Richard Stephenson, Cambridge University Press, 1997, page 125. "Nothing can be surprising any more or impossible or miraculous, now that Zeus, father of the Olympians has made night out of noonday, hiding the bright sunlight, and . . . fear has come upon mankind. After this, men can believe anything, expect anything. Don't any of you be surprised in future if land beasts change places with dolphins and go to live in their salty pastures, and get to like the sounding waves of the sea more than the land, while the dolphins prefer the mountains." May refer to a total solar eclipse of 6 April 648 BC. Archilochus, Greek poet (c680-640 BC) Quoted in Historical Eclipses and Earth's Rotation , by F Richard Stephenson, Cambridge University Press, 1997, page 338. Partly quoted in Encyclopaedia Britannica CD 98 . ECLIPSE QUOTES
- 134. 1882 Transit (USNO)
- 135. Application to Exo Planet Studies HD 209458 (mv = +7.7) in Pegasus
- 136. When the moon is new or full, the gravitational forces of the sun and moon are pulling at the same side of the earth. (See the diagram below.) This occurrence creates the extra large "spring" tides. When the moon is at first and third quarter, the gravitational forces of the sun and moon are pulling at 90 degrees from each other. (see the diagram below.) This occurrence yeilds little net tides called neap tides.
- 137. More Fun Tidal Tales…. Every few years people that measure such things (chronologists?) need to add a leap second to the year. The Earth's rotation is decelerating at a rate of about 0.002 seconds per day per century. The Earth will eventually stop slowing down – when it’s rotation is equal to the moon’s orbital period !!! The Proxigean Tide occurs when the Moon is at its closest point in its orbit to the Earth and in its New or Full Moon phase. At this time, its tidal effect on the Earth is maximum. The times when this will happen often coincide with major coastal flooding events. Between 1997 and 2020 there will be 102 times when this will happen. The moon shows the same face to the Earth because it was deformed by Earth’s gravity when it was still molten. Earth uses this “memory” to grab the moon and slow its spin rate down. WHY ?
- 138. Which one is the smallest? Which one is the largest? <ul><li>Can you put these in size order? </li></ul><ul><li>Place the following in order from largest to smallest. </li></ul><ul><ul><ul><li>Moon </li></ul></ul></ul><ul><ul><ul><li>Sun </li></ul></ul></ul><ul><ul><ul><li>Earth </li></ul></ul></ul>
- 139. Answer: Sun, Earth, then moon <ul><li>The sun is the largest </li></ul><ul><li>Next in size is the Earth. </li></ul><ul><li>The moon is smaller than the Earth. </li></ul>
- 140. <ul><li>Which of these is the biggest? </li></ul><ul><li>F The moon </li></ul><ul><li>G The Earth </li></ul><ul><li>H The sun </li></ul><ul><li>J Jupiter </li></ul>
- 141. Answer: H The sun is the largest! Our sun is the only star in our solar system. The sun is also the largest heavenly body in our solar system.
- 142. The Axis of the earth <ul><li>The axis of the earth is imaginary line that passes through the north pole and the south pole. </li></ul><ul><li>The earth is inclined at an angle of 66.5 degree to the plane of its orbit. </li></ul><ul><li>This is known as the angle of inclination. </li></ul><ul><li>The northern point of the axis always face the pole star. </li></ul>
- 143. EARTH MOVEMENTS INFANT JESUS SCHOOL <---
- 144. Earth is not stationary. <ul><li>* Always in constant motion. </li></ul><ul><li>The Earth moves, in two ways. </li></ul><ul><li>It rotates on an axis (period = 1 day). </li></ul><ul><li>It revolves around the sun (period = 1 year). </li></ul>
- 145. • Rotation:- earth rotates on its own axis from west to east. This movement is known as ROTATION • The earth takes 23 hours & 56 minutes & 4.09 seconds to complete one rotation. The average time required for the earth’s rotation from one sunrise to another sunrise is 24 hours. This period is known as a solar day.
- 146. Each team will need a scorekeeper ---> Effects of Rotation Life on earth is affected in many was as the earth spins on its own axis. Day & night are the result of the earth’s rotation. As the earth rotates on it’s axis only one half of the earth faces to sun at a given time. It is a day on the side of the earth which is turned towards the sun and receives light, & night for the other half of the earth which is away from the sun and is covered in darkness.
- 147. <ul><li>Different stages of the day like morning, noon and evening are experienced because of the earth’s rotation. </li></ul><ul><li>Sun, moon, stars & planets seem to rise in the east & set in the west. </li></ul><ul><li>This is due to rotation of the earth. </li></ul><ul><li>With the rising sun as the point of reference, it is possible to have a sense of other directions as well. </li></ul>
- 148. Midnight Noon Sunrise Sunset The Earth rotates towards the east (CCW) The Earth’s Rotation: Daily Motion
- 149. Revolution <ul><li>The earth revolves around the sun as well. This movement around the sun is known as the earth’s revolution. </li></ul><ul><li>It takes a year for the earth to go around the sun once. </li></ul>
- 150. The Earth’s Revolution: Annual Motion Fall Stars Spring Stars Summer Stars Winter Stars
- 151. The reasons for seasons – the Earth travels around the sun, and its axis of rotation is tilted by 23.5 degrees to the plane of the orbit. In July, the northern hemisphere is getting more sunlight than in January. The heliocentric model
- 152. Earth’s tilt causes seasons <ul><li>? </li></ul>Note typo “rotation”
- 153. Summer: Earth tilted toward the sun <ul><li>More concentrated light when the sun is higher in the sky (fig 1-14) </li></ul><ul><li>Time the sun is up is longer: rises farthest north on summer solstice </li></ul><ul><li>Southern hemisphere: opposite season </li></ul>
- 154. Sunlight and space travel
- 155. Distances <ul><li>If you drive on a highway at 60 k.m.s per hour </li></ul><ul><ul><li>in one hour you may get to Hiriyuru. </li></ul></ul><ul><ul><li>Steady speed! </li></ul></ul><ul><li>If you keep on driving after 4 hours you would reach Bangalore. </li></ul><ul><ul><li>Steady speed - no stops! </li></ul></ul>
- 156. If we could keep on and on - - <ul><li>If you could drive to the Moon </li></ul><ul><li>at 70 miles per hour, </li></ul><ul><li>230,000 miles or about 400,000 km </li></ul><ul><li>it would take you 3400 hours, </li></ul><ul><li>or 140 days. </li></ul>
- 157. Light and heat comes from the Sun <ul><li>It is a long way away ! </li></ul><ul><li>146 million km or 93 million miles </li></ul><ul><li>If you could drive to the Sun at 70 miles per hour </li></ul><ul><li>it would take over 50 000 days. </li></ul><ul><li> = 150 years </li></ul><ul><li> – longer than we live ! </li></ul>
- 158. Light travels very, very fast! <ul><li>Guess how long it takes for light to </li></ul><ul><li>come from the SUN to the Earth. </li></ul><ul><ul><li>8 years </li></ul></ul><ul><ul><li>8 days </li></ul></ul><ul><ul><li>8 hours </li></ul></ul><ul><ul><li>8 minutes </li></ul></ul>
- 159. It takes 8 minutes for light to reach us from the Sun! Light travels 300 000 kilometres through space every second!
- 160. Shadows <ul><li>Light travels in a straight line. </li></ul><ul><li>If something gets in its path the light is blocked. </li></ul><ul><li>A shadow is formed. </li></ul>
- 161. Shadows <ul><li>How do they form? </li></ul>Sun
- 162. We can make shadows ! - by blocking out the light. Changing positions varies the size of the shadow. If you are close to the lamp, the shadow is large. If you are close to the screen, the shadow is smaller.
- 163. Day and Night <ul><li>A day + a night = 24 hours </li></ul><ul><li>365 of these makes 1 year. </li></ul><ul><li>The Earth takes 1 year to orbit the Sun. </li></ul><ul><li>(What does ‘orbit’ mean?) </li></ul>
- 164. The Earth is a ball (or sphere) <ul><li>The Sun cannot shine on both sides of the Earth at the same time </li></ul><ul><li>Some of the Earth is bright - day </li></ul><ul><li>Some is dark – night </li></ul><ul><li>The Earth spins so each part has day and night. </li></ul>
- 165. Day and night <ul><li>Daylight in the UK </li></ul>Light from the Sun Dark in China Dusk in India Light Dark
- 166. At midday here <ul><li>It is dawn in the USA </li></ul><ul><li>It is dusk in India </li></ul>
- 167. As the Earth spins the position of the Sun varies. <ul><li>Morning – the sun rises - it is light. </li></ul><ul><li>The Sun gets higher in the sky. </li></ul><ul><li>Then the Sun sinks and sets. </li></ul>
- 168. Shadows move during the day <ul><li>Watch the shadow of the stick </li></ul><ul><ul><li>to tell the time </li></ul></ul><ul><ul><li>like a sundial. </li></ul></ul>stick 6.00 pm 12.00 noon 6.00 am
- 169. The seasons: the Sun provides light and heat but - <ul><li>winter is cold </li></ul><ul><li>summer is warmer </li></ul><ul><li>What causes this? </li></ul>
- 170. The Four Seasons INFANT JESUS SCHOOL Next Slide
- 171. Seasons <ul><li>What do your students think causes the seasons? </li></ul>http://nix.ksc.nasa.gov/info
- 172. True color images June December March September
- 173. What Causes Earth’s Seasons? <ul><li>Earth’s axis is tilted 23.5 degrees – it always points in the same direction (Polaris, the North Star) as we orbit our Sun once a year </li></ul><ul><li>This tilt causes the hemispheres to alternate in the amount of our Sun’s light and heat they receive through the year </li></ul>http://www.lpi.usra.edu/education/skytellers/seasons/about.shtml
- 174. Earth’s tilt causes seasons <ul><li>? </li></ul>Note typo “rotation”
- 175. Northern Hemisphere Summer More daylight hours, more direct sunlight INFANT JESUS HIGH SCHOOL, CHALLAKERE
- 176. Earth’s orbit is almost a perfect circle <ul><li>Earth is CLOSEST to our Sun (91 million miles) in winter —January 3 </li></ul><ul><li>Earth is farthest from on our Sun (94 million miles) in summer –July 4 </li></ul>
- 177. Height of Sun Winter: The Sun rises in the southeast, stays low in the sky, and sets in the southwest. Spring: The Sun rises due east, moves higher in the sky than in winter, and sets due west. Summer: The Sun rises in the northeast, travels high (near zenith), and sets in the northwest. Fall: The Sun rises due east, travels to a medium-height in the sky, and sets due west.
- 178. Seasons higher=> more intense p. 21 fig 1-14 Solar efficient design
- 179. Winter <ul><li>Winter is the coldest season. </li></ul><ul><li>In the winter, it snows. </li></ul><ul><li>North pole is inclined away from the sun from 22 nd of December. </li></ul><ul><li>So the Northern Hemisphere enjoys winter season and Southern Hemisphere the summer seasons. </li></ul><ul><li>Nights are longer, days are shorter in the Northern Hemisphere </li></ul><ul><li>At the same time in the Southern Hemisphere, the days are longer and the nights shorter. </li></ul><ul><li>On December 22 nd , there is 24 hour night at the north pole & 24 hour day at the south pole. </li></ul><ul><li>During the winter there is no vegetation and the animals hibernate. </li></ul><ul><li>The winter is great for making snowmen. </li></ul>Next Slide
- 180. Sun lower in sky in winter Looking south Dec 21
- 181. Spring <ul><li>The vertical rays of the sun fall on the equator on March 21 st , days & nights are equal throughout the world. </li></ul><ul><li>It is spring in the Northern Hemisphere & autumn in the Southern Hemisphere. </li></ul><ul><li>Flowers begin to peak their heads above the ground. </li></ul>Next Slide
- 182. Summer <ul><li>The summer is the hottest season. </li></ul><ul><li>North pole is inclined towards the sun. So the Northern Hemisphere enjoys summer & Southern Hemisphere enjoys winter. </li></ul><ul><li>Days are longer, nights are shorter in Northern Hemisphere. </li></ul><ul><li>In Southern Hemisphere days are shorter & nights are longer </li></ul><ul><li>On June 21 st there is exactly 24 hour day at the north pole and 24 hour night at the south pole. </li></ul><ul><li>The vegetation is fully bloomed and the animals are very active. </li></ul><ul><li>Summer is great for swimming. </li></ul>Next Slide
- 183. Summer: Earth tilted toward the sun <ul><li>More concentrated light when the sun is higher in the sky (fig 1-14) </li></ul><ul><li>Time the sun is up is longer: rises farthest north on summer solstice </li></ul><ul><li>Southern hemisphere: opposite season </li></ul>
- 184. Autumn <ul><li>The vertical rays of the sun fall on Equator on 23 rd of September. </li></ul><ul><li>The duration of days & nights is equal throughout the earth on this day. </li></ul><ul><li>When it is autumn in the Northern Hemisphere, it is spring in the Southern Hemisphere. </li></ul>Next Slide
- 185. In which season do the leaves begin to change colors? (Select the correct answer) <ul><li>Winter Spring </li></ul><ul><li>Summer Autumn </li></ul>
- 186. This answer is incorrect <ul><li>Please review the lesson and then choose the correct answer. </li></ul>Click to repeat question
- 187. Correct!!!! <ul><li>The leaves begin to change colors and fall off the trees in autumn. </li></ul>Next Slide
- 188. Summer and winter <ul><li>In winter the Sun stays low in the sky. </li></ul><ul><li>In summer the Sun rises higher in the sky. </li></ul>Winter Summer The horizon
- 189. Summer and winter <ul><li>The earth is tipped as it spins </li></ul><ul><li>Light and heat reach the Earth at different angles in summer and winter </li></ul><ul><li>In winter the light and heat from the Sun is more spread out than during the Summer. </li></ul><ul><ul><li>It feels colder </li></ul></ul><ul><ul><li> We can try an experiment. </li></ul></ul>Sun Summer Winter Beam of light Earth Earth
- 190. Leap year <ul><li>Earth requires 365 ¼ days to complete one revolution. </li></ul><ul><li>The year is calculated for 365 days. </li></ul><ul><li>The difference of ¼ day is adjusted once in 4 years and that year has 366 days. </li></ul><ul><li>It is called a leap year. </li></ul><ul><li>During leap year, February has 29 days. </li></ul>
- 191. Effects
- 192. What have we learned? (Sunlight takes 8 minutes to reach the Earth.) <ul><li>Shadows form when light is blocked out. </li></ul><ul><li>Night is when no sunlight reaches us. </li></ul><ul><li>We can tell the time by shadows. </li></ul><ul><li>In winter the Sun is low in the sky. </li></ul><ul><li>The moon reflects light to the Earth. </li></ul><ul><li>Its shape changes because of shadows. </li></ul>
- 193. equinoxes and solstices <ul><li>Equinox: </li></ul><ul><li>‘ equal night’: 12 hours daylight </li></ul><ul><li>Sun’s rays are overhead at the equator on March 21 & Sep 23 rd </li></ul><ul><li>On these days the day & nights are of equal duration throughout the world. </li></ul><ul><li>These days are called equinoxes </li></ul><ul><li>Sun rises due east, sets due west </li></ul>
- 194. sunlight sunlight Vernal Equinox – 21 March equator antarctic circle arctic circle tropic of Cancer tropic of Capricorn
- 195. Solistices <ul><li>Sun’s rays fall vertically over the tropic of cancer & the sun appears stands still at this position and further moves towards the equator. </li></ul><ul><li>On sept 23 rd , the sun’s rays fall vertically over the tropic of capricorn. </li></ul><ul><li>The position of 22 nd June is called Summer Solstice in the Northern Hemisphere & 23 rd of Sept is called winter solstice. </li></ul><ul><li>Means marking of winter in Northern Hemisphere </li></ul>
- 196. equinoxes and solstices <ul><li>Solstices : “sun stops” and heads back </li></ul><ul><li>Summer solstice: June 21/22 </li></ul><ul><li>longest number of daylight hours, </li></ul><ul><li>sun sets farthest north, rises farthest north </li></ul><ul><li>most concentrated sunlight </li></ul><ul><li>Winter Solstice: Dec 21/22 </li></ul>
- 197. p. 23
- 198. Keep asking questions! <ul><li>There is lots to find out! </li></ul>
- 199. Let's play . . . Rotation OR Revolution JEOPARDY ! Rules --->
- 200. Each team will need a scorekeeper ---> RULES 1. Each team will get a turn. 2-3 teams . 2. Each question is worth 3 points . 3. If a team misses a question, they forfeit 1 point . 4. The QUESTION to each ANSWER is either rotation or revolution . 5. Each answer must be in the form of a QUESTION. 6. Applause = Correct Explosion = Incorrect
- 201. Round One 1. The Earth spinning on its axis. Rotation Revolution 2. Going around a larger body. Rotation Revolution Revolution 4. Causes the Earth’s seasons. Revolution Rotation 5. Creates a year. 3. 24 hours. Rotation Revolution Revolution Rotation 6. The moon going around Earth. Revolution Rotation Go on to Round Two --->
- 202. Round Two Identify the motion being shown in each of these pictures. Each team must write their answers for each figure in the form of a question. Earth Figure #1 Rotation Revolution Figure #2 Rotation Revolution Final Round ---> Planet
- 203. Each team must confer and write the amount of points they would like to risk on the Final Round - The topic is Seasons .
- 204. X CLICK HERE FOR A FINAL MESSAGE Which team had most points? You’re all WINNERS!!! SUN The Final Round Identify the Season being shown in this picture.---> Winter Fall Summer Spring Choose the correct tree-->
- 206. Earth Patterns,Cycles, and Change <ul><li>The sun heats the Earth unevenly, making the poles cold and the tropics hot, because- </li></ul><ul><li>A the tropics face more directly </li></ul><ul><li>toward the sun </li></ul><ul><li>B the poles are covered with ice </li></ul><ul><li>which causes cold air </li></ul><ul><li>C seasons change </li></ul><ul><li>D weather changes </li></ul>
- 207. <ul><li>The moon revolves around - </li></ul><ul><ul><li>F itself </li></ul></ul><ul><ul><li>G the Earth </li></ul></ul><ul><ul><li>H the sun </li></ul></ul><ul><ul><li>J the solar system </li></ul></ul>
- 208. <ul><li>The moon revolves or orbits the Earth once every 29 days. </li></ul><ul><li>We all ways see the same side of the moon because the moon rotates and revolves at about the same speed. </li></ul>
- 209. Earth Science Question: rotation <ul><li>What is rotation? (define) </li></ul><ul><li>The rotation of the Earth on its axis causes- </li></ul><ul><ul><li>A days </li></ul></ul><ul><ul><li>B months </li></ul></ul><ul><ul><li>C seasons </li></ul></ul><ul><ul><li>D years </li></ul></ul>
- 210. Rotation causes day & night. <ul><li>Rotation is the turning or spinning of the Earth in one place on its imaginary axis. </li></ul><ul><li>Rotation of the earth on its axis causes day & night. (answer A). </li></ul>
- 211. Earth Science Question: <ul><li>Which of these shows the location of a polar ice cap? </li></ul><ul><li>Which of these shows the location of the equator? </li></ul>B A C C D
- 212. Polar ice caps= A Equator= C 0º latitude 90º latitude
- 213. Which of these is caused by the turning of the Earth? <ul><ul><li>F Summer and winter </li></ul></ul><ul><ul><li>G Stars </li></ul></ul><ul><ul><li>H Day and night </li></ul></ul><ul><ul><li>J Moon phases </li></ul></ul>
- 214. The turning of the Earth causes <ul><li>Day & Night </li></ul>
- 215. When the moon is seen from the Earth as a whole circle, it is called a- <ul><ul><li>A Crescent moon </li></ul></ul><ul><ul><li>B Full moon </li></ul></ul><ul><ul><li>C Half moon </li></ul></ul><ul><ul><li>D New moon </li></ul></ul>
- 216. When the moon is seen from the Earth as a whole circle, it is called a FULL MOON.
- 217. Which of these is the next phase of the moon? <ul><li>New Moon --- Waxing Crescent --- ? </li></ul><ul><li>F Full Moon </li></ul><ul><li>G Waning Crescent </li></ul><ul><li>H First Quarter </li></ul><ul><li>J Waxing Gibbous </li></ul>
- 218. The next major phase of the moon would be… <ul><li>First quarter. </li></ul><ul><li>Just think about it…the </li></ul><ul><li>New moon (can only get bigger. Or = Waxing).. </li></ul><ul><li>Then comes Waxing crescent …next is </li></ul><ul><li>First quarter …then </li></ul><ul><li>Waxing Gibbous and then a </li></ul><ul><li>Full Moon . </li></ul>
- 219. The revolution of the Earth around the Sun takes- <ul><ul><li>A a day & night or 12 hours </li></ul></ul><ul><ul><li>B a week or 7 days </li></ul></ul><ul><ul><li>C a month or 29-31 days </li></ul></ul><ul><ul><li>D a year or 365 days </li></ul></ul>
- 220. The revolution of the Earth around the sun <ul><li>Takes 365 days </li></ul><ul><li>or one year. </li></ul><ul><li>NOTE: </li></ul><ul><li>Due to the tilt of the Earth’s axis during revolution, the Earth experiences seasons. </li></ul>
- 221. Unnderstanding Longitude & Latitude
- 222. LATITUDES & LONGITUDES
- 225. What is Latitude? <ul><li>Latitude is the distance from the equator along the Y axis. </li></ul><ul><li>All points along the equator have a value of 0 degrees latitude. </li></ul><ul><li>North pole = 90 °N </li></ul><ul><li>South pole = 90 °S </li></ul><ul><li>Values are expressed in terms of degrees. </li></ul>Y X 90 °S 90 °N
- 226. What is Latitude? <ul><li>Each degree of latitude is divided into 60 minutes. </li></ul><ul><li>Each minute is divided into 60 seconds . </li></ul>Y X 90 °S 90 °N This is also true of longitude.
- 227. What is Latitude? <ul><li>For Example: </li></ul><ul><li>37 °, 02’,51’’N </li></ul><ul><li>This is close to the latitude where you live. </li></ul>Y X 90 °S 90 °N
- 228. What is Longitude? <ul><li>Longitude is the distance from the prime meridian along the X axis. </li></ul><ul><li>All points along the prime meridian have a value of 0 degrees longitude. </li></ul><ul><li>The earth is divided into two parts, or hemispheres, of east and west longitude. </li></ul>Y X 180 °W 180 °E
- 229. What is Longitude? <ul><li>The earth is divided into 360 equal slices (meridians) </li></ul><ul><li>180 west and 180 east of the prime meridian </li></ul>Y X 180 °W 180 °E
- 230. What is Latitude? <ul><li>Our latitude and longitude might be: </li></ul><ul><li>37 °, 03’,13’’N </li></ul><ul><li>76°, 29’, 45’’W </li></ul>Y X 90 °S 90 °N
- 231. So Where is (0,0)? <ul><li>The origin point (0,0) is where the equator intersects the prime meridian. </li></ul><ul><li>(0,0) is off the western coast of Africa in the Atlantic Ocean. </li></ul>
- 232. See If You Can Tell In Which Quarter These Lon/Lats Are Located <ul><li>1. 41 °N, 21°E </li></ul><ul><li>2. 37°N, 76°W </li></ul><ul><li>3. 72°S, 141°W </li></ul><ul><li>4. 7°S, 23°W </li></ul><ul><li>5. 15°N, 29°E </li></ul><ul><li>6. 34°S, 151°E </li></ul>A B C D
- 233. <ul><li>1. B </li></ul><ul><li>2. A </li></ul><ul><li>3. C </li></ul><ul><li>4. C </li></ul><ul><li>5. B </li></ul><ul><li>6. D </li></ul>Let's See How You Did!
- 234. <ul><li>Latitude ( shown as a horizontal line ) is the angular distance, in degrees, minutes, and seconds of a point north or south of the Equator. Lines of latitude are often referred to as parallels. </li></ul>
- 235. <ul><li>Any location on Earth is described by two numbers--its latitude and its longitude. If a pilot or a ship's captain wants to specify position on a map, these are the "coordinates" they would use. Actually, these are two angles, measured in degrees, "minutes of arc" and "seconds of arc." These are denoted by the symbols ( °, ', " ) e.g. 35° 43' 9" means an angle of 35 degrees, 43 minutes and 9 seconds (do not confuse this with the notation (', ") for feet and inches!). A degree contains 60 minutes of arc and a minute contains 60 seconds of arc--and you may omit the words "of arc" where the context makes it absolutely clear that these are not units of time. </li></ul><ul><li> </li></ul>
- 236. <ul><li>Calculations often represent angles by small letters of the Greek alphabet, and that way latitude will be represented by λ (lambda, Greek L), and longitude by φ (phi, Greek F). Here is how they are defined. </li></ul><ul><li> Imagine the Earth was a transparent sphere (actually the shape is slightly oval; because of the Earth's rotation, its equator bulges out a little). Through the transparent Earth (drawing) we can see its equatorial plane, and its middle the point is O, the center of the Earth. </li></ul><ul><li>To specify the latitude of some point P on the surface, draw the radius OP to that point. Then the elevation angle of that point above the equator is its latitude λ--northern latitude if north of the equator, southern (or negative) latitude if south of it. </li></ul>
- 237. LATITUDE <ul><li> Imagine the Earth was a transparent sphere (actually the shape is slightly oval; because of the Earth's rotation, its equator bulges out a little). Through the transparent Earth (drawing) we can see its equatorial plane, and its middle the point is O, the center of the Earth. </li></ul><ul><li>To specify the latitude of some point P on the surface, draw the radius OP to that point. Then the elevation angle of that point above the equator is its latitude λ--northern latitude if north of the equator, southern (or negative) latitude if south of it. </li></ul><ul><li> </li></ul>
- 238. <ul><li>Latitude angle </li></ul><ul><li>Lines of latitude </li></ul>
- 239. <ul><li>[How can one define the angle between a line and a plane, you may well ask? After all, angles are usually measured between two lines ! Good question. We must use the angle which completes it to 90 degrees, the one between the given line and one perpendicular to the plane. Here that would be the angle (90°-λ) between OP and the Earth's axis, known as the co-latitude of P.] </li></ul><ul><li> On a globe of the Earth, lines of latitude are circles of different size. The longest is the equator , whose latitude is zero, while at the poles--at latitudes 90° north and 90° south (or -90°) the circles shrink to a point. </li></ul>
- 240. LONGITUDE <ul><li>Longitude ( shown as a vertical line ) is the angular distance, in degrees, minutes, and seconds, of a point east or west of the Prime ( Greenwich ) Meridian. Lines of longitude are often referred to as meridians. </li></ul>
- 241. <ul><li>On the globe, lines of constant longitude ("meridians") extend from pole to pole , like the segment boundaries on a peeled orange. </li></ul><ul><li> </li></ul>
- 242. <ul><li>Every meridian must cross the equator. Since the equator is a circle, we can divide it--like any circle--into 360 degrees, and the longitude φ of a point is then the marked value of that division where its meridian meets the equator. </li></ul>
- 243. <ul><li>A lines of longitude is also called a meridian , derived from the Latin, from meri , a variation of "medius" which denotes "middle", and diem , meaning "day." The word once meant "noon", and times of the day before noon were known as "ante meridian", while times after it were "post meridian." Today's abbreviations a.m. and p.m. come from these terms, and the Sun at noon was said to be "passing meridian". All points on the same line of longitude experienced noon (and any other hour) at the same time and were therefore said to be on the same "meridian line", which became "meridian" for short. </li></ul>
- 244. Positioning on the Earth’s Surface Latitude and Longitude together enable the fixing of position on the Earth’s surface. Equator Latitude 0 o Latitude: ( 90 o N to 90 o S) Latitude 23½ o North Tropic of Cancer Latitude 23½ o South Tropic of Capricorn Longitude 30 o East Longitude 60 o East Longitude 30 o West Longitude 60 o West East is the direction of rotation of the Earth North Pole South Pole 23½ o 23½ o 66½ o 90 o 90 0 21 st June 22 nd December 22 nd Sept 20 th March 30 o E 60 o E 90 o E 90 o W 30 o W 60 o W Longitude 90 o East Longitude 90 o West Prime Meridian 0 o Longitude Longitude: (180 o E to 180 o W)
- 245. <ul><li>See if you can find those same latitude/longitude locations on a map! </li></ul>
- 246. Now you’re ready to find some locations on a map!
- 247. Longtitude & Time <ul><li>Earth rotates on its own axis & takes 4 minutes to rotate to one degree of longitude and one hour to rotate 15 degree of longitudes. </li></ul>
- 248. Local time <ul><li>When the sun is overhead on a particular longitude it is 12 noon at all the places located on that longitude. </li></ul><ul><li>One degree longitude on either side of this longitude will be 4 minutes behind on its west and 4 minutes ahead on its east. </li></ul><ul><li>It is known as local time. </li></ul><ul><li>There are 360 degrees longitudes, so there are 360 local times. </li></ul>
- 249. Standard Time <ul><li>Local time cannot be used by railways, telegraphs & other international offices. </li></ul><ul><li>In such cases the Standard Time is used. </li></ul><ul><li>The longitude which passes in the centre of a particular nation is known as Standard meridian. </li></ul>
- 250. In Summary!

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JESUS HIGH SCHOOL

what in the world would name a school that?