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

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

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 EffectSpring Tide – When

the sun and moon are aligned and the tides are HIGHER than normal

Neap Tide – When the moon and sun are at right angles and the 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.

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

EclipsesWhat 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 moon 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