do now (in notebooks) where did the earth’s moon come from? what is the biggest effect the moon...
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Do Now (In Notebooks)
Where did the Earth’s Moon come from?
What is the biggest effect the moon has on Earth?
Essential QuestionWhat if there was no moon?
ObjectivesStudents will be able to:
Describe formation theories of the moonDescribe how the moon affects tides
Identify the phases of the moonProvide the mechanism for eclipses
Differentiate between solar and lunar eclipses
Where did the moon come from? There are three theories of the
moon’s formation: Capture Theory Simultaneous Formation Theory Impact Theory
Capture Theory
Moon caught by Earth’s gravitational pull
Problems: What slowed the Moon? Why are the compositions so similar?
Simultaneous Formation Theory
Moon and Earth formed at same general time in same general area
Problem: Why does Earth
have so much more iron?
Why doesn’t the moon have water like the Earth?
Impact Theory
Earth collided with a Mars-sized object
Materials from collision came together to form moon
Explosion evaporated water
The Moon’s Features
Highlands Areas light in color Mountainous
Maria Dark smooth regions From Eruptions
Impact craters Regolith
Loose, ground up rock
Radius - 1737.4 km About 1/4th of Earth’s
How does the How does the Moon affect us?Moon affect us?
Tides
Periodic rise and fall of the level of the ocean
The moon’s gravity pulls on Earth
Gravity creates build up of ocean water on both near and far sides of the Earth
The ocean water build up stays in line with the moon
The ocean level rises and falls every 12 hours
Tidal Range
Vertical distance between low and high tide
1- 2 m on East Coast of North America
Bay of Fundy – 20 meters
Tides
Semidiurnal Tide 2 high tides and 2
low tides in 24 hours
Diurnal Tide one high tide and
one low tide in 24 hours
The Sun’s Effect
Spring Tide When the sun and
moon are aligned Tides are HIGHER
than normal Neap Tide
When the moon and sun are at right angles
Tides are LOWER than normal
Sun vs. Moon Does the Sun or the Moon have a larger
effect on tides?
THE MOON!!
*Even though the moon is smaller than the Sun, the moon is much closer to the Earth, and therefore has a larger effect on the tides.
Do Now – In Notebooks
What is the most likely theory of the Moon’s formation?
Draw the Sun, Earth, and Moon as they are arranged during a neap tide.
Phases of the MoonWhat if there was no moon?
What causes the moon’s phases? The moon does not emit visible light The moon is visible due to reflected
sunlight One side (1/2) of the moon is always
lit As the moon rotates around Earth,
the light reflected by the moon changes, causing phases
Phase Names
Gibbous Crescent Quarter moon Full Moon New Moon
Waxing Vs. Waning
Waxing Increase in visible, sunlit portion of the
moon “Right” side of moon is visible
Waning Decrease in visible, sunlit portion of the
moon “Left” side of the moon is visible
Phase Names
Waxing Crescent First Quarter Waxing Gibbous Full Moon Waning Gibbous Third Quarter Waning Crescent
Eclipses
What if there was no moon?
Eclipses
One object moves into the shadow of another
Named for the celestial body that is blocked
Lunar Eclipse
Moon passes into Earth’s shadow
Reflected light from the sun is blocked, instead moon seems red
Can only occur during full moon
Occur slightly more frequently than solar
Solar Eclipse
Moon passes between Earth and Sun Only see outer layers of sun Occurs during new moon
Regions of Solar Eclipse
Umbra Area does not receive sunlight, total
eclipse Penumbra
Receives partial sunlight, partial eclipse
Why don’t we have monthly eclipses?
The moon’s orbit is tilted compared to Earth
Eclipses only occur when orbits line up
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