EARTH, SUN, AND MOON

EARTH’S ROTATION Earth rotates on it’s axis Axis-imaginary line passing through the North and South Pole Tilted at 23 ½ degrees Rotation-one full spin on it’s axis, which is one 24-hour day and night cycle

EARTH’S ROTATION-VIDEO CLIP ( 1 min. 29 sec.)

EARTH’S REVOLUTION Earth revolves around the sun Revolution-the movement of one object orbiting around another in space It takes the Earth 365 ¼ days to revolve around the sun= 1 year

EARTH’S REVOLUTION Earth’s revolution around sun is elliptical, not spherical Apogee- point in orbit where the Earth and Sun are farthest apart Perigee-point in orbit where the Earth and Sun are closest together

APOGEE (APHELION)-SUMMER PERIGEE (PERIHELION)-WINTER

REASON FOR THE SEASONS VIDEO

WHY SEASONS? Seasons occur due to the revolution of the Earth around the Sun and due to the tilt of the Earth on it’s axis

SUMMER North pole pointed toward the sun More direct sunlight hitting the northern hemisphere Summer in northern hemisphere=winter in the southern hemisphere Summer solstice occurs around June 21=longest day and shortest night

WINTER North pole points away from sun Less direct light hits northern hemisphere Winter in northern hemisphere=summer in southern hemisphere Winter solstice occurs around Dec. 21=shortest day and longest night

SPRING AND FALL Poles neither tilted toward or away from sun Spring Equinox occurs around March 21 Autumnal Equinox occurs around September 23 Spring and Autumnal Equinox: equal length of daylight and nighttime hours in both hemispheres

MOON’S ORBIT On average Moon is about 250,000 miles away from Earth Mass is only 1/6 that of Earth Apogee-moon furthest from Earth in it’s orbit Perigee-moon closest to Earth in it’s orbit

MOON APPEARS BIGGER DURING PERIGEE

MOON’S ORBIT Orbits the Earth every 27.3 days Rotates on axis every 27.3 days There are 9 phases of the moon that we see Takes approximately 29.5 days to go through all phases

NEW MOON-PHASE 1 Earth, Sun, and Moon in alignment, Moon between Earth and Sun Moon rises when the sun rises and sets when the sun sets, crosses the sky with the sun during the day so we can’t see it Shadow side of the moon is facing us

WAXING CRESCENT-PHASE 2 Sunlit portion is increasing During a waxing crescent, we can see only a small section on right that is shaped like a crescent

FIRST QUARTER MOON-PHASE 3 Moon is at a 90 degree angle with respect to the earth and sun. So we are seeing exactly half of the moon illuminated (right half) and half in shadow. Now through first quarter or ¼ of the way through the moon phases

WAXING GIBBOUS-PHASE 4 Sunlight increasing on right side, more than ½ full now

FULL MOON-PHASE 5 Earth, Moon, and Sun are in alignment, Earth between Moon and Sun Sun is so much bigger than Earth, it’s light shines right over it Sunlit portion is facing us, shadowed portion hidden from view

WANING GIBBOUS-PHASE 6 Sunlight increasing on left side, shadow starting on right side now Still over half full

3 RD QUARTER MOON-PHASE 7 Moon is at a 90 degree angle with respect to the earth and sun. So we are seeing exactly half of the moon illuminated (left half) and half in shadow. Now through ¾ of the way through the moon phases

WANING CRESCENT-PHASE 8 Sunlit portion is decreasing During a waning crescent, we can see only a small section on left that is shaped like a crescent

BACK TO NEW MOON-PHASE 9

MR. PARR SINGS THE MOON PHASE SONG!

SOLAR ECLIPSE Moon is directly in path between Earth and Sun (New Moon only) Moon’s shadow hits the Earth, temporarily blocking the Sun Umbra-densest, darkest part of shadow (no light=total eclipse) Penumbra-lighter part of the shadow (partial light=partial eclipse)

LUNAR ECLIPSE The umbra of the Earth’s shadow hits moon Occurs only during a full moon

LUNAR ECLIPSE VIDEO 1 min. 51 sec.

THE MOON AND TIDES Moon and Sun play important role in cycle of tides on Earth Moon plays a stronger role than Sun Types of Tides: High Low Spring Neap

HIGH TIDE Moon’s gravity pulls water on Earth nearest to Moon towards it Creates “bulge” in water that faces moon Also creates high tide on opposite side of earth

LOW TIDE Water on sides of Earth perpendicular to high tides Usually 2 high and 2 low tides each day

LOW AND HIGH TIDES VIDEO

SPRING TIDES Occur when Sun, Earth, and Moon are in alignment New Moon or Full Moon only Gravity of all 3 combined creates very high high tides and very low low tides

NEAP TIDES Sun and Moon are perpendicular to the Earth 1 st and 3 rd quarter moons Gravity of Sun and Moon come close to cancelling each other out Not big difference between a high and low tide

SPRING AND NEAP TIDES VIDEO