1. Sun-Earth-Moon System Ch 20

2. Section 1: Earth’s Motion I)Earth and Sun A) Earth is ALWAYS moving (even though we don’t feel it) B) Around the Sun 1) Nearest star – 150 million km away from Earth 2) 100 times bigger than Earth 3) Mass is 300,000 times greater 4) Inside Sun: *Nuclear Fusion – nuclei of atoms combine releasing HUGE amounts of energy! * SMALL part (of Sun’s energy) reaches EARTH!

3. Sect. 1 Cont. C) Earth’s movement around Sun 1) Revolution ~ motion of one object around another object. 2) Orbit ~ the path an object follows as it moves around another object. *Earth’s path is not a perfect circle (close but not quite) – ellipse. 3) 365.24 days … (Know why we have leap year?? Make up for that.24!!) 4) Earth revolves around Sun because of … SUN’s GRAVITY pulls on Earth. 5) Demo … ball on string

4. Sect. 1 Cont. D) Earth ROTATES on its axis. 1) Causes ~ day (part of Earth facing Sun) and night (part of Earth away from Sun)! 2) Rotation ~ is spinning motion. 3) Rotation axis ~ line on which an object rotates. 4) Rotates COUNTERCLOCK wise.

5. Sect. 1 Cont. 5) Earth rotates from WEST to EAST ~ causing … * Sun / stars / moon to appear to move from East to West. 6) Earth’s axis is tilted ~ sometimes tilted toward Sun … sometimes away.

6. Sect. 1 Cont. II)Shape of Earth A) Sphere – causes different parts to receive different amounts of Sun’s energy. * Equator - more direct Sunlight /warmer (receives more energy) * Northern / Southern Hemisphere - more spread out / colder (receives less energy)

7. Sect. 1 Cont. B) Earth is Tilted 23.5 degrees … * INFLUENCES our SEASONS! III) Seasons A) Cause of Seasons ~ combination of 1) TILT !!! 2) Revolving around SUN 3) REMEMBER ~ *CLOSEST to Sun in WINTER *FARTHEST to Sun in SUMMER *TILT is what makes us warmer or cooler! http://www.youtube.com/watch?v=DuiQvPL WziQ

8. Sect. 1 Cont. B) Solstice (Def: day when Earth’s rotation axis is the most toward or away from the sun) 1) December Solstice (Winter for us) *Northern Hemisphere – shortest day and longest night. (Tilted AWAY from Sun) *Southern Hemisphere – longest day and shortest night. (Tilted TOWARD Sun)

9. Sect. 1 Seasons Cont. 2) June Solstice (Summer for us) *Northern Hemisphere is tilted TOWARD Sun. - Longest day and shortest night. *Southern Hemisphere is tilted AWAY from Sun. (Their winter) - Shortest day and longest night.

10. Sect. 1 Seasons Cont. C) Equinox (Def ~ day when Earth’s rotation axis is leaning along Earth’s orbit neither toward nor away from Sun.) 1) September Equinox *Northern Hemisphere = Fall 12 hours day and night. *Southern Hemisphere = Spring 2) March Equinox *Northern Hemisphere = Spring 12 hours day and night *Southern Hemisphere = Fall

11. Websites Teachers Domain – seasons There is a “tutorial” on the book website too.

12. End Sect. 1 Assignment … Worksheets – yes due tomorrow!

13. Sect. 2 ~ The MOON I)Moon info A)Formation: 1)Shortly after Earth formed – Mars size planet hit Earth. 2)Sent vaporized rock into ring around Earth. 3)Eventually, formed into our Moon.

14. I) Moon Info cont. B) Surface: No atmosphere or liquid water or plate tectonics to change surface. 1)Craters - bowl shaped dip from space objects crashing into the Moon. 2)Maria – dark flat areas that formed from lava hardening. 3)Highlands – light colored areas w/ craters (too high for the lava to cover so no maria there) … oldest area on moon. 4)Rays – bright streaks around craters.

15. I) Moon’s Info. Cont. C) Moon’s Motion 1) Revolves around Earth in 27.3 days – gravitational pull of Earth on Moon. 2) Rotates counterclockwise around in 27.3 days – means … #3) IMPORTANT … same side of Moon faces Earth at all times!!! *Side we see = NEAR side *Side we do not see = FAR side

16. II) Phases of Moon Phases – portion of Moon lit up by Sun (part we see – some planets also have phases). A)Waxing Phases – increasing light on Moon (DRAW!!) **Right side lit up** 1)Waxing Crescent 2)1 st Quarter 3)Waxing Gibbous 4)Full Moon Moon Earth Sun in a line

17. II) Phases Cont. B) Waning Phases – light is decreasing ** Left side lit up ** 1)Waning Gibbous 2)3 rd Quarter or Last 3)Waning Crescent 4)New Moon No lightEarth Moon Sun in a line

18. Website …

19. Assignment ~ Worksheets

20. Sect. 3 ~ Eclipses and Tides I)Eclipses: produced by shadows of Earth or Moon. A)Parts of a shadow: 1)Umbra i)Darkest part of a shadow ii)In the center or middle 2)Penumbra i)Lighter part of a shadow (light is partially blocked. ii)On the sides … or outside of the umbra

21. I) Eclipses – cont. B) Solar Eclipse 1) Def: Moon’s shadow appears on Earth’s surface. 2) Position: Earth Moon Sun (New Moon Phase) 3) Total – occurs only for those in Umbra. 4) Partial – occurs for those in Penumbra. 5) Why don’t we have one every New Moon? *Moon’s orbit is tilted about 5 degrees from Earth’s orbit so they rarely line up for Solar Eclipse.

22. Website http://www.teachersdomain.org/asset/ess05_ vid_totaleclipse/ http://www.teachersdomain.org/asset/ess05_ vid_totaleclipse/ How many people see a solar eclipse? Very few – Moon’s shadow is small compared to Earth.

23. I) Eclipses cont. C) Lunar Eclipse: 1) Def: Moon moves into Earth’s shadow. 2) Position: Sun, Earth, Moon in a line – can ONLY occur during Full Moon. 3) Total and Partial occur. 4) Again – doesn’t happen every full moon due to Moon’s orbit

24. Website: http://www.youtube.com/watch?v=IKQkM474 UE0&feature=related http://www.youtube.com/watch?v=IKQkM474 UE0&feature=related How many people can see a lunar eclipse? Anyone on Earth who can see the moon – more than can see a solar eclipse. How often can one occur? About every 6 months.

25. II) Tides A)Def: 1)Daily rise and fall of sea level. 2)Bulges of Earth’s Oceans. 3)P. 748 Figure 20 … High & Low Tide B)Happens: twice each day. C) Cause: 1)Moon’s gravitational pull on Earth. 2)Sun’s gravitational pull has a smaller effect – causes “special” ones …

26. II) Tides cont. D) where Moon & Sun’s grav. work together. 1) Spring Tides: Full & New Moon phase – E, M, S lined up. *HIGH tides are higher than usual. *LOW tides are lower than usual. 2) Neap Tides: S, E, M form a right angle (90 deg.) *HIGH tides are lower than usual. *LOW tides are higher than usual. (P. 748 Fig. 21 bottom of page)

27. Finished Chapter – Whew! Review assignment: P. 753 Copy and do Concept Map (8-15) P. 754 (1-10 Multiple Choice) P. 755 SENTENCES!! (14, 16, 17)