1. Earth Motions 1)Rotation – the spinning of an object on its axis. (Like a figure skater or a CD) 2)Direction of Rotation – Earth turns west to east or counterclockwise when looking from the Northern Hemisphere. 3)Parallelism of the axis – Earth’s axis remains parallel to itself throughout its orbit. Axis of Rotation

2. Which Way Is Counterclockwise?

3. Earth’s Axis and Revolution

4. 1)Foucault Pendulum – evidence of Earth’s rotation. In the 19 th century no direct observation of Earth’s rotation had been made. Foucault determined that a pendulum could be set up so that it did not turn along with the Earth. This caused it to appear to turn. The pendulum appears to turn because the Earth turns underneath it. Here’s the pendulum in action! Evidence and Effect of Rotation

5. 2)Coriolis Effect – more evidence of Earth’s rotation. The observed impact of Earth’s rotation on objects and winds as they move north or south through the Earth’s atmosphere. Objects are deflected to the RIGHT in the Northern Hemisphere Animation

6. 3)All of the objects on the “celestial sphere” appear to move from east to west during a day/night cycle. Timed exposures show the lines (a.k.a. star trails) of light as stars “move” across the sky.

7. Measuring Celestial Arcs 0 45 90 135 180 225 270 315

8. How long was this timed exposure? Line = 15 o Rotation Rate = 15 o /hr Time = 1 hour 0 45 90 135 180 225 270 315

9. Sunset from Mauna Kea 4)Day and Night Cycle – the Sun appears to travel around us.

10. 1)Revolution – the movement of an object around another in space. 2)Evidence of Revolution – Seasons, the movement of the Sun relative to the backdrop of distant stars, and the apparent change in size of the Sun. 3)The Earth Revolves in counterclockwise direction around the Sun. Revolution

11. 4) Rate of revolution: 360 o / 365.26 days = 1 o per day Revolution

12. Retrograde Motion

13. Dance of the Planets

15. Down to Earth: Viewing the Cosmos from Home What is the celestial sphere? The imaginary dome of the sky, on which all of the stars, planets, our Moon and the Sun move. Zenith – The highest point on the celestial sphere (directly overhead). Altitude – The angular height of an object above the horizon. Horizon – The rim of the Earth at the edge of sight were the sky appears to meet the ground. The Celestial Sphere

16. Azimuth

17. Altitude

18. Measuring Altitude

19. Summer Solstice Winter Solstice Equinox The Sun’s rays are never vertical in New York State and you must always look to the SOUTH to see the Sun at solar noon Zenith Polaris

20. Summer SolsticeWinter Solstice Equinox To have vertical rays, you must be located between the Tropic of Cancer (23.5  N) and the Tropic of Capricorn (23.5  S) Zenith Polaris

21. Summer Solstice Winter Solstice Equinox Zenith Polaris The Sun never gets higher in the sky than 23.5 o altitude at the North Pole (June 21 st ) and is below the horizon for the fall and winter!

22. How do we calculate the Sun’s maximum altitude at noon throughout the year in the Northern Hemisphere? Equinox (either one): Altitude = 90 o – latitude June Solstice: Altitude = 90 o – latitude + 23.5 o December Solstice: Altitude = 90 o – latitude – 23.5 o

23. At the Equinox:

24. June Solstice:

25. December Solstice

26. Base your answer on the diagram, which shows sunlight entering a room through the same window at three different times on the same winter day. This room is located in a building in New York State. On which side of the building is the window located?

27. Do Now Please take out your Birthday Moon activity from Thursday, and also have out a blank piece of paper!

28. How many times per year do we see a full moon in the sky? Answer: 12 or 13, depending on the year 12.37 per year

29. 1) Facts about the Moon Its orbit is elliptical with the Earth at one focus. Its motion is cyclical (regular, predictable) Direction of both rotation and revolution is counter- clockwise

30. Its periods of rotation and revolution are almost identical; therefore, we have only seen a little more than 50% of the Moon’s surface from Earth.

31. Far From Earth Close To Earth The apparent diameter of the Moon changes in a cyclic manner due to its changing distance from Earth AphelionPerihelion

32. Moon has more impact craters on its surface than Earth due to: – Lack of atmosphere – Lack of erosion – Lack of water

33. How much of the Moon’s sphere is lit up by the Sun at any one time? 50 %

34. Find the Sun’s Rays!

37. Moon phases are cyclical (repetitive) Moon phases are caused by the revolution of the Moon around the Earth At any time, exactly half of the Moon is illuminated by the Sun

44. Tides are caused by gravitational pull of the Moon and the Sun on the Earth’s oceans The Moon has the greatest influence on the tides due to the fact that it is much closer to the Earth

45. The Bay of Fundy – Low Tide

46. The Bay of Fundy – High Tide

47. Sun, Earth and Moon are in a line. Very high tide and very low tide. Large difference between high & low tides.

48. Sun, Earth and Moon are at right angles. Moderate high tide and moderate low tide. Small difference between high & low tides.

49. The total or partial blocking of light when one celestial body moves into the shadow of another celestial body 4) Eclipses

50. Types of shadows cast during an eclipse. Umbra – The “dark” portion of an eclipse shadow where a total eclipse can be seen. Penumbra – The “light” portion of an eclipse shadow where a partial eclipse can be seen. 4) Eclipses

52. We do not have a lunar and a solar eclipse each month because the Moon’s orbit is tilted by approximately 5 degrees!