Phases and Eclipses

Phases and Eclipses

Middle School

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Learning Objectives

• Develop and use a model of the Earth-Sun-Moon system to describe cyclic patterns.

• Describe how the Moon's orbit and reflection of sunlight cause the pattern of lunar phases.

• Explain why the same side of the Moon always faces the Earth.

• Differentiate between a solar and a lunar eclipse based on their alignment.

• Explain why the Moon's tilted orbit makes eclipses a rare event.

Key Vocabulary

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Model

A model is a representation used to describe or explain how a system works.

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Cyclic Pattern

A cyclic pattern describes a series of events that repeat in the same order.

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Solar Energy

Solar energy is the radiant light and heat that originates directly from the sun.

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Rotation

Rotation refers to the circular movement of an object spinning around its own central axis.

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Revolution

Revolution is the movement of one object as it travels in an orbit around another.

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Tilted Orbit

The moon's orbit has a tilted orbit, meaning it is slanted at about 5 degrees.

Key Vocabulary

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Phases

The phases of the moon describe the different shapes the sunlit portion of the moon appears to have from Earth.

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New Moon

This is the phase when the moon's unlit side, its dark side, is directly facing towards the planet Earth.

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Full Moon

This is the lunar phase when the side of the moon that is facing the Earth is completely illuminated.

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Eclipse

An eclipse happens when one celestial object blocks the light from another celestial object or a spacecraft from view.

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Solar Eclipse

A solar eclipse occurs when the moon's shadow falls on the Earth, blocking the sunlight from our view.

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Lunar Eclipse

This type of eclipse happens when the Earth's shadow falls on the moon, darkening it from our view.

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The Earth-Sun-Moon System Model

• Scientists use models to predict patterns and events in nature.

• This system model helps explain phenomena like phases and eclipses.

• Earth rotates on its axis daily and revolves around the Sun yearly.

• We see the moon because sunlight reflects off its surface.

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Multiple Choice

What is the primary purpose of a scientific model like the Earth-Sun-Moon system model?

• To predict patterns and events in nature

• To create exact copies of real-world objects

• To prove that scientific ideas are always correct

• To replace the need for making observations

Multiple Choice

Which statement best explains how we are able to see the Moon?

• The Moon is visible because it reflects light from the Sun.

• The Moon produces its own light, like the Sun.

• The Earth's rotation makes the Moon appear to shine.

• The Earth's atmosphere illuminates the surface of the Moon.

Multiple Choice

Based on the components of the Earth-Sun-Moon system, what phenomena can be explained by Earth's daily rotation and yearly revolution?

• The model would be used to explain why we experience a day-night cycle and a yearly cycle of seasons.

• The model would primarily focus on why the Sun appears to move across the sky.

• The model would no longer be useful for predicting any natural events.

• The model would only be used to explain the phases of the Moon.

The Moon's Appearance and Motion

• The changing shapes of the moon we see are called phases.

• We always see the same side of the moon, called the near side.

• The moon rotates and revolves around Earth at the same rate.

Multiple Choice

What are the different shapes of the Moon that we observe from Earth called?

• Phases

• Rotations

• Revolutions

• Tides

Multiple Choice

What is the primary consequence of the Moon rotating and revolving at the same rate?

• The Moon appears to change shape throughout the month.

• The same side of the Moon always faces Earth.

• The Moon completes one orbit around Earth each day.

• The Earth and Moon are the same age.

Multiple Choice

What would most likely happen if the Moon began to rotate significantly slower than it revolves around Earth?

• The Moon would no longer show any phases.

• We would be able to observe all sides of the Moon over time.

• The Moon would appear to be significantly larger in the sky.

• The Earth would stop rotating on its axis.

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The Phases of the Moon

• The phase you see depends on the sunlit part visible from Earth.

• ​The cycle begins with a new moon, waxing crescent, and first quarter.

• Illumination increases to a full moon, then decreases through waning phases.

• This entire predictable cycle of phases repeats about every 29.5 days.

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Multiple Choice

What determines the phase of the moon that we see from Earth?

• The amount of the moon's sunlit side that is visible from Earth.

• The shadow of the Earth falling onto the moon's surface.

• The distance between the Earth and the moon during its orbit.

• The cloud cover in the Earth's atmosphere at night.

Multiple Choice

What is the key difference between the moon's waxing and waning phases?

• The visible sunlit portion is increasing during waxing phases and decreasing during waning phases.

• Waxing phases occur before a new moon, and waning phases occur after.

• The moon appears larger during waxing phases and smaller during waning phases.

• Waxing phases are only visible in the spring, and waning phases in the fall.

Multiple Choice

If a full moon is observed on a specific date, what phase should be expected approximately 15 days later?

• A first quarter moon

• A new moon

• Another full moon

• A waning crescent

What Are Eclipses?

• An eclipse happens when one object in space blocks another, casting a shadow.

• During a solar eclipse, the Moon blocks the Sun's light from reaching Earth.

• During a lunar eclipse, Earth's shadow covers the Moon.

Multiple Choice

What is the definition of an eclipse?

• An event where one object in space blocks another, casting a shadow.

• An event where a planet completes one full rotation on its axis.

• An event where a star in space burns out and explodes.

• An event where two celestial objects collide with each other.

Multiple Choice

What causes a solar eclipse to occur?

• The Moon passes between the Sun and Earth, blocking the Sun's light.

• The Earth passes between the Sun and the Moon, blocking the Sun's light.

• The Sun moves to a position that is behind the Moon.

• The Earth's atmosphere bends the light from the Sun.

Multiple Choice

For Earth's shadow to cover the Moon during a lunar eclipse, what must be the alignment of the three bodies in space?

• The Sun, Earth, and Moon are aligned in that specific order.

• The Sun, Moon, and Earth are aligned in that specific order.

• The Moon is at a right angle to the Earth and Sun.

• The Earth and Moon are on opposite sides of the Sun.

Eclipse Shadows and Rarity

• The moon's tilted orbit means its shadow usually misses Earth, making eclipses rare.

• The umbra is the darkest part of the shadow, causing a total eclipse.

• The penumbra is the lighter shadow area, creating a partial eclipse for observers.

Multiple Choice

What is the primary reason that solar eclipses are rare events?

• Because the moon's orbit is tilted, its shadow often misses Earth.

• Because the moon is much smaller than the sun.

• Because the Earth's atmosphere blocks the moon's shadow.

• Because eclipses can only happen at night.

Multiple Choice

What is the relationship between the different parts of the moon's shadow and the type of eclipse an observer sees?

• The umbra is the lighter part of the shadow and causes a partial eclipse, while the penumbra is the darkest part and causes a total eclipse.

• The umbra is the darkest part of the shadow and causes a total eclipse, while the penumbra is a lighter shadow that causes a partial eclipse.

• The umbra and penumbra are both equally dark, but they appear at different times during an eclipse.

• The umbra is the shadow of the Earth, while the penumbra is the shadow of the moon.

Multiple Choice

An observer is located within the moon's penumbra. What conclusion can be drawn about the type of eclipse they will experience?

• A total eclipse, because they are in the darkest part of the moon's shadow.

• A partial eclipse, because they are in the lighter, outer part of the moon's shadow.

• No eclipse, because the penumbra is not part of the actual shadow.

• A total eclipse, because the penumbra is larger than the umbra.

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Common Misconceptions

Misconception	Correction
The moon's phases are caused by Earth's shadow.	Phases are our view of the moon’s sunlit side as it orbits Earth.
The 'dark side' of the moon never receives sunlight.	The far side gets sunlight and experiences a full day and night cycle.
Solar and lunar eclipses happen every single month.	The moon’s tilted orbit makes eclipses rare events.

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Summary

• The Earth-Sun-Moon system is a model for cyclic patterns like phases.

• Phases are caused by the changing angles of the sunlit moon.

• We always see the same side of the moon due to its synchronous rotation.

• Solar and lunar eclipses are rare shadow events due to the moon's 5-degree tilt.

Poll

On a scale of 1-4, how confident are you about using the Earth-Sun-Moon model to explain phases and eclipses?

• 1

• 2

• 3

• 4