3. 5. Because the earth really rotates from west to east, or counterclockwise, an observer (person standing in one spot on earth)
anywhere on earth will see sunrise (sun appears over horizon in morning)
towards the east and the sunset (disappear below the horizon in evening) towards the west.

4. 6. Where the sun is during the rest of the day depends on the observer's latitude
Latitude is degrees north or south of the equator.
7. For New York State, the sun is always in our southern sky during the day.

5. 8. At solar noon we say the sun has reached its highest point of the day. In New York State, the sun is never ever ever directly over our heads. (In other words, the sun is never at zenith in New York State).

6. 9. Evidence of rotation:
a. Coriolis Effect is the deflection of wind and water from straight line motion. If the earth did not rotate, winds and water would not curve, they’d go in a straight line.

7. b. Foucault Pendulum appears to change direction in a circle during 24 hours. However, the pendulum is actually going in a straight line, it is the room that is rotating around it!!!

8. c. Circumpolar constellations (always above the horizon) move around Polaris during the night, giving the suggestion that we rotate.

13. ^^^^The altitude of Polaris, equals the latitude of the observer in the Northern Hemisphere.
WE live at 41 degrees North. How high is Polaris for us????

14. Concept 2: Revolution and seasons
1. Revolution is an object moving continuously around another object due to gravity.
Earth is a satellite (object revolving around another object) of the sun.
from classaction, planetary motion

16. 3. Ancient proofs of earth's revolution:
a. Seasons (change in weather in a cyclic fashion). The amount of sunlight and intensity changes monthly.
The size of the sun changes during the year. We are CLOSER to the sun in WINTER.

17. Parallax of stars:
closer stars seem to shift position relative to farther stars during the year.

18. Seasonal constellations: the constellations we see in fall are different than those we see in winter, spring, etc. The change is cyclic.
earth orbit and seasonal stars

19. Models of the Solar System (and universe)
Geocentric Model: earth-centered.
Heliocentric Model: sun-centered.(Copernican model)
retrograde motion and the ptolemic and Copernican explanations
ptolemic retrograde due to epicycles
copernican retrograde due to Earth moving faster

20. 4. Causes of Seasons;
a. Tilt of axis: our axis is tilted, with reference to the sun's rays, at an angle of 23.5o (look at any globe)
b. Parallelism of the axis: our North Pole always points toward Polaris. (see wall chart)

21. c. Revolution: We orbit the sun on a tilted planet, causing different parts of the earth to have more light seasonally.

22. 5. Important dates:
Equinoxes: “equal night”. Sun is overhead at equator. September 22 and March 21
Solstice: ‘sun stop’. Sun is either at Tropic of Capricorn (winter begins December 21) or Tropic of Cancer (summer begins June 21).
Each day, the sun seems to move a little bit between 23.5 North and 23.5 South

23. Actual position of sunrise changes with seasons, but is always east
Position of sunset changes with seasons, but is always west.

24. http://phys23p. sl. psu. edu/phys_anim/astro/embederQ4. 20100
ptolemic retrograde
copernican retrograde
from classaction, planetary motion
ptolemic phases of venus
retrograde animation
physics animations
earth orbit and seasonal stars

25. C= 2 x 92 million x 3.14 = 580 million miles orbit
Speed of orbit = 580 million miles / 365 days = 1.6 million miles / day
Hours in a day = 24
Speed per hour = 1.6 million miles/ day x 1day/ 24 hours = 67, 000 mph