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Earth in Space

Earth in Space

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Earth in Space

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  1. Earth in Space

  2. Rotation • Rotation is the Earth turning on its axis • Rotation is responsible for day and night • The Earth rotates in a counter-clockwise direction • 1 rotation takes 24 hours • Earth rotates at a speed of 1670 km/hr or 1035 mph (circumference of the Earth at the Equator is 40,000km) (Speed=distance/time) • We do not feel the speed of Earth’s rotation due to Newton’s First Law of Motion (object in motion stays in motion unless acted upon by an outside force)

  3. Revolution • Revolution is the movement of the Earth around the sun • It takes 365.25 days (1 year) for the Earth to complete one revolution • The Earth revolves around the sun in an elliptical shaped orbit

  4. Revolution • To make up for the extra ¼ day that is takes the Earth to revolve around the sun, an extra day is added to February every 4 years • This is called a Leap Year • February 29, 2012 is our next Leap Year

  5. Seasons(Seasons described relative to the Northern Hemisphere) • Seasons are caused by the Earth’s 23.5o tilt on its axis. • Earth is tilted toward the sun in the summer and away from the sun in winter. • http://www.classzone.com/books/earth_science/terc/content/visualizations/es0408/es0408page01.cfm?chapter_no=04 • www.brainpop.com (seasons)

  6. Summer • We experience the season of summer when the North Pole is directed a full 23.5o toward the sun • Due to the positioning of the North, more direct rays of the sun are present in the summer • There are longer periods of daylight and shorter nights in the summer

  7. Summer • Due to the longer days and more direct rays, the temperatures in summer are hottest. • The Earth is actually furthest from the sun in our elliptical orbit in the summer

  8. Winter • In the winter, the North Pole is directed a full 23.5oaway from the Sun • There are shorter days and longer nights in the winter • The Earth is further from the sun in its elliptical orbit in the winter • Due to the shorter days and less direct rays of the Sun, the temperatures in winter are coldest

  9. Northern and Southern Hemispheres • The seasons are different in the Northern and Southern Hemispheres because of Earth’s tilt on its axis • In June, the Northern Hemisphere is tilted toward the sun and people are experiencing summer and the Southern Hemisphere is tilted away from the sun and people are experiencing winter

  10. Solstice • Solstice means Sun and stop • The solstice is the time when the sun stops moving higher or lower in the sky each day • The Summer Solstice is the first day of summer (June 20 or 21) • The Summer Solstice is the longest day of the year and the Sun reaches its highest point in the sky • The North Pole is at “full tilt” toward the sun

  11. Solstice • The Winter Solstice is the first day of winter (December 21 or 22) • The Winter Solstice is the shortest day of the year. The sun appears at its lowest point in the sky. • The North Pole is at “full tilt” away from sun

  12. Equinox • Equinox is Latin for equal night • The Vernal Equinox is the first day of spring (March 20 or 21) • Day and night are of equal length all over the world during the Equinox

  13. Equinox • The Autumnal Equinox is the first day of fall (September 22 or 23)

  14. Websites • http://www.usatoday.com/weather/tg/wseason/wseason.htm(Earth’s tilt creates the 4 seasons) • http://esminfo.prenhall.com/science/geoanimations/animations/01_EarthSun_E2.html

  15. Earth and Seasons Quiz • 1. Name the four seasons. ___ • spring,summer, fall,winter • 2. Are the Earth's seasons caused by the differences in the distance from the Sun throughout the year or the tilt of the Earth's axis? • Tilt of Earth’s axis • 3. What is the tilt of the Earth's axis (in degrees)? • 23.5*

  16. 4. During which season do the Sun's rays hit the Earth at the most direct angle? • Summer • 5. During which season are the days the shortest? • Winter • 6. What is the name of the shortest day of the year (and the beginning of winter)? • Winter Solstice

  17. 7. What is the name of the longest day of the year (and the beginning of summer)? Summer solstice • 8. What is the name of a day in which the day and night are of equal duration? Equinox • 9. How many times each year do we have days in which the day and night are of equal duration? 2 times • 10. What are the names of each of these days? the vernal equinox and the autumnal equinox