I. Earth’s Days, Years, and Seasons Vocabulary 1. Rotation 2. Day 3. Revolution 4. Year 5. Season 6. Equinox 7. solstice

A.What determines the length of a day? 1. Axis= an imaginary straight line that runs from the North pole to the South pole through the center of the Earth 2. Rotation= the spinning of a body on its axis Takes 23 hr 56 min and 4.1 sec for Earth to make one full rotation on its axis= one day When one half of Earth is facing the sun (daytime) the other half is dark away from the sun (nighttime)

B.What determines the length of a Year? 1. Revolution= motion of a bod that travels around another body in space 2. Earth revolves around the sun ~30km/s (~18mi/s) 3. Year= one full revolution of the Earth around the sun= 365 ¼ days 4. Earth’s orbit is elliptical not a circle= closer to the sun in Jan.

C.What conditions are affected by the tilt of the Earth’s axis= Temperature 1. Earth’s axis is 23.5° always pointed toward the North star 2. Earth’s axis causes unequal heating of the Earth’s surface Equator gets most direct sunlight= warmer Sun angles towards the poles= cooler

D.Hours of daylight are affected by Earth’s axis 1. Area around equator receives around 12 hrs of daylight all of the time 2. Summer in the Northern hemisphere the axis is toward the sun= more daylight 3. Arctic circle has 24 hrs of daylight in the summer and almost no hours of daylight in the winter

E.What causes seasons? 1. Season are characterized by a pattern of temperature and other weather trends 2. Closer to the equator the less change there is 3. Equinox= sunlight shines equally on the Northern and Southern Hemispheres 4. Solstice= area of sunlight is at a max in one hemisphere and a min in the other

a. September Equinox= Earth’s position allows both poles to have equal amounts of sunlight (Sept 22/23) b. December Solstice= North Pole is leaning away from the sun and has complete darkness- South pole is in complete sun (Dec 21/22) c. March Equinox= Both poles have equal light again (March 20/21) d. June Solstice= North pole leaning towards the sun and is on complete sunlight with the South pole in complete darkness (June 21/22)

II. Moon Phases & Eclipses Vocab= 1. Satellite 2. Gravity 3. Lunar phases 4. Eclipse 5. Umbra 6. penumbra phases

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A.Earth, Moon & Sun relation in space 1. Satellite= a body that orbits another larger body in space Natural satellite= moon 6 planets in our solar system have moons (not Mercury & Venus) 2. Earth’s mass is much greater than the moon so it has a stronger pull keeping the moon in orbit Amount of gravity relies on size and distance of two objects 3. Earth/moon system orbits around the sun b/c the sun’s mass is so enormous the gravitational pull can overcome the distance

B. View of the moon from Earth 1. The moon is only visible when it reflects the sun’s light 2. Darker and lighter areas of the moon are caused by high and low elevations (craters) 3. Only one side of the moon faces Earth “near side” Moon rotates once on its own axis each time it orbits Erath Moon takes 27.3 days ~month to orbit Earth once

C.Lunar Phases 1. Lunar phases= changes in the moons appearance as it revolves around the Earth throughout the month 2. Phases throughout the month: a. New moon= Earth, moon and sun are lined up and the unlit side is facing the Earth (dark) b. Waxing crescent= growing sliver of the moon

c. First quarter= half of the sunlit portion of the moon is visible (end of 1 st week) d. Waxing gibbous= more than half (but not all) of the near side of the moon is visible (2 nd week) e. Full moon= the entire near side of the moon is visible (end of 2 nd week) f. Waning gibbous= near (sunlit) side starts to decrease (3 rd week) g. Third quarter= half of the moon is visible

h. Waning crescent= near side of the moon has a crescent view left (4 th week) i. New moon near side of the moon is unlit

D.Lunar Eclipses Eclipse= event during which one object in space casts a shadow on to another 2. Lunar eclipse= When moon moves into earth’s shadow a. Umbra= darkest part of a shadow (total eclipse) b. Penumbra= lighter part of the shadow (partial eclipse)

E.Solar Eclipse Moon is directly between the sun and the Earth & the moon’s shadow falls onto part of the Earth 2. Total= umbra of the moon totally blocks the sun on a small part of the Earth 3. partial-= penumbra of the moon blocks some of the sun

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