1. The Moon

2. Students will be able to:
Essential Question
What if there was no moon?
Objectives
Students will be able to:
Describe formation theories of the moon
Describe how the moon affects tides
Identify the phases of the moon
Provide the mechanism for eclipses
Differentiate between solar and lunar eclipses

3. Where did the moon come from?
There are three theories of the moon’s formation:
Capture Theory
Simultaneous Formation Theory
Impact Theory

4. Capture Theory Moon caught by Earth’s gravitational pull Problems:
What slowed the Moon?
Why are the compositions so similar?

5. 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?

6. Impact Theory Earth collided with a Mars-sized object
Materials from collision came together to form moon
Explosion evaporated water

7. How does the Moon affect us?

8. 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

9. The ocean water build up stays in line with the moon
The ocean level rises and falls every 12 hours

10. Tidal range – vertical distance between low and high tide
1- 2 m on East Coast of North America
Bay of Fundy – 20 meters

11. Semidiurnal Tide Diurnal Tide 2 high tides and 2 low tides in 24 hours
one high tide and one low tide in 24 hours

12. The Sun’s Effect
Spring 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

13. 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.

14. What if there was no moon?
Phases of the Moon
What if there was no moon?

15. 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

16. Phase Names
Gibbous
Crescent
Quarter moon
Full Moon
New Moon

17. Waxing Vs. Waning Waxing Waning
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

18. Phase Names Waxing Crescent First Quarter Waxing Gibbous Full Moon
Waning Gibbous
Third Quarter
Waning Crescent

20. What if there was no moon?
Eclipses
What if there was no moon?

21. Eclipses One object moves into the shadow of another
Named for the celestial body that is blocked

22. 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

24. Solar Eclipse Moon passes between Earth and Sun
Only see outer layers of sun
Occurs during new moon

25. Regions of Solar Eclipse
Umbra
Area does not receive sunlight, total eclipse
Penumbra
Receives partial sunlight, partial eclipse

26. Why don’t we have monthly eclipses?
The moon’s orbit is tilted compared to Earth
Eclipses only occur when orbits line up