2 Students will be able to: Essential QuestionWhat if there was no moon?ObjectivesStudents will be able to:Describe formation theories of the moonDescribe how the moon affects tidesIdentify the phases of the moonProvide the mechanism for eclipsesDifferentiate between solar and lunar eclipses
3 Where did the moon come from? There are three theories of the moon’s formation:Capture TheorySimultaneous Formation TheoryImpact 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 areaProblem: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 moonExplosion evaporated water
8 Tides Periodic rise and fall of the level of the ocean The moon’s gravity pulls on EarthGravity creates build up ofocean water on bothnear and far sides of theEarth
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 AmericaBay 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 EffectSpring Tide – When the sun and moon are aligned and the tides are HIGHER than normalNeap Tide – When the moon and sun are at right angles and the tides are LOWER than normal
13 Sun vs. MoonDoes 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 MoonWhat if there was no moon?
15 What causes the moon’s phases? The moon does not emit visible lightThe moon is visible due to reflected sunlightOne side (1/2) of the moon is always litAs the moon rotates around Earth, the light reflected by the moon changes, causing phases