# Space Cycles Review. Cycle # 1 Day  Night  Day  Night.

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Space Cycles Review

Cycle # 1 Day  Night  Day  Night

We have day and night because the Earth ROTATES On it’s axis Once every 24 ¼ hours ½ of the Earth is illuminated (lit up) at a time http://www.gcse.com/eb/day2.gif

Cycle #2 The length of days Long  Longer  Longest  Longer  Long  Short  Shorter  Shortest  Short  Shorter  Shortest  Long  Longer  Longest

The length of day changes during the year The number of hours of daylight is different at different times of the year The number of hours of daylight is different at different latitudes

Summary Days are longer (more hours of daylight) in summer, shorter in winter There are greater differences in day length further away from the Equator There is not much change in day length near the Equator

Summary Days get LONGER (more minutes of daylight each day) from the Winter Solstice to the Summer Solstice Days get SHORTER (fewer minutes of daylight each day) from the Summer Solstice to the Winter Solstice Day length is about EQUAL everywhere in the world on the Autumnal & Vernal Equinox

Why does the length of day change? Because the Earth moves, or REVOLVES around the Sun This changes the way sunlight hits the Earth

Cycle # 3 The Seasons Winter  Spring  Summer  Fall  Winter  Spring  Summer http://www.getyourwebsitehere.com

Seasons are caused by The tilt of the Earth The position of Earth in space The difference in direct and indirect light from the Sun

Summary In winter: –Part of the Earth is tilted AWAY from the Sun –Part of the Earth gets INDIRECT energy from the Sun In summer –Part of the Earth is tilted TOWARD the Sun –Part of the Earth gets DIRECT energy from the Sun The position of the Earth in space determines which part of the planet is tilted toward the Sun.

Cycle # 4 Moon Phases New moon  Waxing Crescent  1 st Quarter  Waxing Gibbous  Full Moon  Waning Gibbous  3 rd Quarter  Waning Crescent  New Moon

The Moon A moon phase cycle (LUNAR CYCLE) lasts 29 1/2 days Moon phases are caused by the positions of the Moon, Sun, and Earth The moon also sees Earth phases

http://www.astro.virginia.edu What we see on Earth compared to the position of the moon in space

DAY 1 The Moon's unilluminated (not lit by the Sun) side is facing the Earth. The Moon is not visible. New Moon

DAY 3 The Moon seems to be getting bigger – more of the lit side is showing. WAXING CRESCENT Getting bigger: WAXING The RIGHT ½ of the moon is lit Less than ½ the moon showing: CRESCENT

FIRST QUARTER DAY 7 One-half of the Moon is illuminated by direct sunlight. One half of one half of the moon is visible.

Waxing Gibbous DAY 11 The Moon is more than one-half but not fully illuminated by direct sunlight. GIBBOUS: more than half of the moon is visible.

Full Moon DAY 14 The Moon's illuminated side is facing the Earth. The Moon is completely illuminated by direct sunlight.

Waning Gibbous DAY 17 The Moon is more than one-half but not fully illuminated by direct sunlight. Waning: getting smaller. Moon is lit on the LEFT side

Last Quarter DAY 22 One-half of the Moon is illuminated by direct sunlight.

Waning Crescent DAY 24 The Moon is less than one-half illuminated by direct sunlight.

http://www.facstaff.bucknell.edu

Summary

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