Unit 4: AstronomyChapter 12: Earth, Moon, & Sun

Big Idea: The motions of Earth & the moon & their position relative to the

sun result in day & night, the seasons, phases of the moon, eclipses, & tides

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4 Sections

1. Earth in Space

2. Gravity & Motion

3. Phases, Eclipses, & Tides

4. Earth’s Moon

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Sec 1: Earth in Space

KEY CONCEPTS

• Earth moves through space in 2 major ways:

1) rotation

2) revolution

• Earth has seasons because its axis is tilted as it revolves around the sun

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Sec 1: Key Terms

• Astronomy• Rotation• Orbit• Solstice

• Axis• Revolution• Calendar• Equinox

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Sec 2: Gravity & Motion

KEY CONCEPTS• The strength of the force of gravity between 2 objects

depends on 2 factors:1) the masses of the objects2) the distance between them

• Newton concluded that 2 factors:1) inertia2) gravity

combine to keep Earth in orbit around the sun & the moon in orbit around Earth

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Sec 2: Key Terms

• Force• Gravity• Law of universal

gravitation

• Mass• Weight• Inertia• Newton’s 1st law of

motion

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Sec 3: Phases, Eclipses, & Tides

KEY CONCEPTS• The changing relative positions of the moon,

Earth, & sun cause the phases of the moon, eclipses, & tides

• The phase of the moon you see depends on how much of the sunlit side of the moon faces Earth When the moon’s shadow hits Earth or Earth’s shadow hits the moon, an eclipse occurs

• When the moon’s shadow hits Earth or Earth’s shadow hits the moon, an eclipse occurs

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Sec 3: Phases, Eclipses, & Tides (cont’d)

• A solar eclipse occurs when the moon passes directly between Earth & the sun, blocking sunlight from Earth

• During a lunar eclipse, Earth blocks sunlight from reaching the moon

• The tides are caused mainly by differences in how much the moon’s gravity pulls on the different parts of Earth

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Sec 3: Key Terms

• Phase• Solar eclipse• Penumbra• Tide• Neap tide

• Eclipse• Umbra• Lunar eclipse• Spring tide

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Sec 4: Earth’s Moon

KEY CONCEPTS• Features on the moon’s surface include maria,

craters, & highlands• The moon is dry & airless. Compared to Earth,

the moon is small & has large variations in its surface temperature

• Scientists theorize that a planet-sized object collided with Earth to form the moon

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Sec 4: Key Terms

• Telescope• Maria• Crater• Meteoroid