# Earth, Moon, and Sun S8.D.3.1.1-3.

## Presentation on theme: "Earth, Moon, and Sun S8.D.3.1.1-3."— Presentation transcript:

Earth, Moon, and Sun S8.D

Earth’s 2 Motions 2. Revolution (orbit) Rotation – go around the Sun
Great Site Earth’s 2 Motions 2. Revolution (orbit) – go around the Sun Rotation – Spin (rotate) on its axis

Rotation The turning of a planet on its axis Axis:
23.5 0 Axis Axis: Imaginary line that runs from the North Pole, through the center of Earth, to the South Pole. Earth’s axis is tilted at We have days and nights because of Earth rotating in and out of sunlight Table of Planets day

Rotation The direction of Earth’s rotation is counterclockwise (when looking from above the North Pole) Because Earth rotates counterclockwise, it appears the Sun rises in the East and sets in the West

Rotation It takes Earth 24 hrs to complete one rotation
One complete rotation of any planet is called a Day At the Equator, Earth rotates 1,000 mph The faster a planet rotates, the shorter the day is on that planet Cool Fact: Earth is slowing down at a rate of seconds per century

Revolution Movement of a planet around the Sun
Counterclockwise (from above NP) One complete revolution of any planet around the Sun is called a year Earth rotates 365 ¼ times during one revolution around the Sun (There are 365 ¼ days in a year) We make up for that extra ¼ day by adding a day to our calendar (Feb 29th) every 4 years Leap Year

Revolution The closer a planet is to the Sun, the shorter its year is , because: It has to travel a shorter distance Its speed is greater due to the Sun’s gravity **Earth Revolves at an average of 67,000 mph

Revolution Orbit - The path a planet follows around the Sun
- Shape is elliptical (Oval) with the Sun off-center (not in the middle!) 95 million miles 91 million miles Average= 93 million miles Perihelion

2 Forces that Keep Earth in Orbit:
Inertia Body in motion will remain in motion Body at rest will remain at rest **Inertia is why the planets keep moving ( in a straight line) Unless acted upon by an outside force Gravity The Sun’s gravity pull planets toward the Sun and keeps them in their orbital path

~15hrs ~12 hrs ~9hrs ~12 hrs Equator Equator Tropic of Cancer
Tropic of Capricorn Equator ~12 hrs

Why is there More Hrs of Daylight in Summer?
24 hrs darkness 24 hrs daylight 24 hrs daylight 24 hrs darkness Why is there More Hrs of Daylight in Summer?

Seasons The seasons in one hemisphere are opposite of the seasons in the other Hemisphere **Seasons in the Southern Hemisphere are more extreme than in the Northern Hemisphere

Tropic of Capricorn (23.50 below Equator)
Tropic of Cancer (23.50 above Equator) Northern Hemisphere Equator Southern Hemisphere Bill Nye- seasons

Seasons Animations: Video clip Bill Nye Seasons Video clip #2

The Moon Revolves around Earth ¼ Earth’s diameter (2,159 miles)
1/6 of Earth’s gravity Frozen water ice at the poles (in deep shadowed craters) Mainly rock and dust (brought back 840lbs of rock to Earth

The Moon NO atmosphere  therefore NO weather
Temp range is large since it lacks an atmosphere 250F = high during the day -250F = low at night Lots of craters from impacts because it lacks an atmosphere Old and unchanged because it lacks an atmosphere

Our Moon Has 2 Motions: Rotation Revolution
counterclockwise 10.7 mph on its axis (6.70) Takes 28 days to rotate once Lunar Day = 28 Earth days Revolution Around Earth at 2,300 mph Orbit is Tilted (5º) Orbit is elliptical (Perigee and apogee) Average distance to the moon is 238,000 miles Lunar Year = 28 Earth days A Day is as long as a Year on the Moon!

Why Don’t We See the Far Side?
The Moon rotates 1 time around its axis as it makes 1 revolution around Earth. It finishes a rotation at the same time it finishes a revolution Period of Rotation = Period of Revolution 28 Earth Days Dark Side FACT: The Moon does not rotate and revolve at the same speed!

Phases of the Moon The Moon reflects sunlight
It does NOT produce its own light We see different phases (shapes) depending on where the moon is in its orbit It takes the Moon about 28 Earth days to complete one revolution around Earth and go through all of its phases

New Moon During a New Moon we can’t see the moon from Earth
The side hit by sunlight is facing AWAY from Earth Occurs when the Moon passes between the Earth and Sun Moon is above or below Earth’s plane 20

Full Moon After a New Moon, the Moon continues to revolve in a counterclockwise direction allowing us to see more and more of the side facing us. (Waxing Phases) When it gets halfway around Earth, we see ALL of the side facing us

Full Moon (cont.) Earth is between the Moon and Sun
Moon is above or below Earth’s plane As the Moon continues to revolve from a full moon position, we see less and less of the side facing us (Waning Phases), until we have another New Moon

Animation Animation

Eclipses Lunar Eclipse Solar Eclipse
Moon is being eclipsed (blocked from our sight) Solar Eclipse Sun is being eclipsed by the moon (blocked from our sight) Moon is 400 x smaller than the Sun Moon can perfectly block out sun because the moon is 400x closer to us than the sun is FACTS: Earth is 4x bigger than Moon Sun is 100x bigger than Earth

Lunar Eclipse Earth is directly between the Sun and a Full Moon (all 3 bodies are in line) Moon is in the shadow of Earth (no sunlight hitting it) Only happens 2-4 times a year (not all total) Zone of partial shadow Zone of complete shadow Whole back side of Earth can see Lunar Eclipse

Solar Eclipse When a New Moon is directly between the Earth and Sun (all 3 bodies are in line) Sunlight is blocked (by the moon) from reaching a small area of Earth, so only people living in that area see the solar eclipse At least 2 a year (not all total) People in penumbra see partial solar People in umbra see total solar

Tides Rising and falling water levels of our oceans
Moon’s and Sun’s gravity makes water bulge out on Earth The Moon’s gravity has a greater effect because it’s closer than the Sun The area aligned with the moon  High Tide The area not aligned with the moon  Low Tide Spring tides Neap tides Bill Nye- Moon