Earth, Sun, and Moon System

Earth, Sun, and Moon System

Middle School

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Learning Objectives

• Describe the physical characteristics of the Sun, Earth, and Moon.

• Explain how gravity governs the motions of the Earth, Sun, and Moon.

• Use a model to describe the causes of lunar phases and eclipses.

• Describe how the tilt of Earth's axis and its orbit cause the seasons.

Key Vocabulary

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Gravity

Gravity is the natural force that attracts any two objects with mass toward each other.

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Orbit

An orbit is the curved path an object in space takes around another one.

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Atmosphere

The atmosphere is a layer of mixed gases that surrounds a planet, moon, or star.

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Sunspots

Sunspots are temporary dark spots on the Sun's surface that are cooler than surrounding areas.

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Solar Flares

A solar flare is a sudden, intense eruption of energy from the surface of the Sun.

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Maria

Maria are the large, dark, flat plains on the Moon's surface, formed by ancient lava flows.

Key Vocabulary

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Craters

Craters are bowl-shaped pits that are formed from impacts on a planet or moon's surface.

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Axis of Rotation

The axis of rotation is an imaginary line that an object, like a planet, spins around.

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Lunar Phase

A lunar phase is the shape of the sunlit portion of the Moon as seen from Earth.

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Revolution

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

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Solar Eclipse

A solar eclipse happens when the Moon passes between the Sun and Earth, blocking the Sun's light.

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Lunar Eclipse

A lunar eclipse occurs when Earth passes directly between the Sun and Moon, blocking sunlight from the Moon.

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The Sun: Our Solar System's Star

• The Sun is a star, a glowing ball of gas, and has no solid surface.

• ​Its core is 15,000,000°C, powered by nuclear reactions that fuse hydrogen.

• Features include dark, cooler sunspots and bright, energetic solar flares.

• The Sun is so large that one million Earths could fit inside of it.

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Multiple Choice

Which of the following statements best describes the Sun?

• A star made of gas that has no solid surface.

• A solid planet with a hot, liquid core.

• A moon that is larger than the Earth.

• A comet composed of ice and rock.

Multiple Choice

What is the relationship between the Sun's core and its ability to glow?

• Nuclear reactions in the core produce enormous energy.

• The Sun's large size creates pressure and heat.

• Sunspots on the surface burn to generate light.

• The gas on the surface is constantly on fire.

Multiple Choice

A sunspot is a 'dark, cooler' area, while a solar flare is 'bright and energetic.' What can you conclude by comparing these two features?

• The sunspot releases less energy than the solar flare.

• The sunspot is made of a different type of gas than the solar flare.

• The sunspot is a hole that shows the Sun's solid surface.

• The sunspot and the solar flare are the same temperature.

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Earth: The Planet of Life

• Earth is a rocky planet with a solid surface and a liquid metal core.

• Its atmosphere traps heat, keeping the planet warm at an average of 15°C.

• The atmosphere also contains the oxygen that living things need to breathe.

• Liquid water, essential for life, covers about 70% of the planet’s surface.

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Multiple Choice

Which statement best describes Earth's physical structure?

• A rocky planet with a solid surface and liquid metal core

• A gas giant with a thick, stormy atmosphere

• A frozen planet covered entirely in ice

• A molten planet with a constantly changing surface

Multiple Choice

What is the relationship between Earth's atmosphere and its ability to support life?

• The atmosphere traps heat and contains oxygen, which are essential for life.

• The atmosphere creates the planet's magnetic field to deflect radiation.

• The atmosphere pushes liquid water to the planet's surface.

• The atmosphere breaks down rocks to create soil for plants.

Multiple Choice

Based on the information provided, what would most likely happen if Earth's atmosphere could no longer trap heat?

• The planet's liquid water would freeze, making it difficult for life to survive.

• The amount of oxygen in the atmosphere would increase.

• The planet's core would become solid.

• The planet would pull closer to the sun.

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Characteristics of the Moon

• The Moon has a rocky surface with highlands and dark, flat plains (maria).

• Its surface is covered with dust and craters from meteorite impacts.

• With no atmosphere, temperatures swing from 123°C during the day to -233°C at night.

• No wind or rain means features like astronaut footprints remain unchanged for centuries.

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Multiple Choice

Which of the following best describes the Moon's surface?

• It is smooth and covered in ice.

• It has a rocky surface with craters and plains.

• It is covered by oceans and continents.

• It has active volcanoes and dense forests.

Multiple Choice

What is the primary reason for the extreme temperature changes on the Moon?

• The Moon is much closer to the Sun than Earth.

• The Moon's rocky surface absorbs too much heat.

• The Moon lacks an atmosphere to regulate temperature.

• The Moon's rotation is very slow.

Multiple Choice

A footprint left by an astronaut on the Moon can remain for centuries. Which statement best explains why?

• It would be broken down and decomposed by bacteria.

• It would be worn away by strong winds.

• It would be washed away by heavy rains.

• It would be mostly unchanged because there is no wind or rain.

Gravity and Orbits

• Gravity is an attractive force between any two objects that have mass.

• The Sun’s strong gravity keeps all the planets in orbit around it.

• Similarly, the Earth’s gravity is what keeps the Moon in its orbit.

Multiple Choice

What is gravity?

• An attractive force between any two objects that have mass.

• A force that pushes objects apart.

• The force that makes objects float in space.

• The energy an object has because of its motion.

Multiple Choice

What is the function of the Sun's gravity in the solar system?

• It keeps the planets in a stable orbit.

• It provides the planets with heat and light.

• It causes the planets to spin on their axes.

• It pushes the planets away from the Sun.

Multiple Choice

If the Earth's gravity suddenly stopped working, what would be the most likely consequence for the Moon?

• The Moon would drift away from Earth into space.

• The Moon would crash directly into the Earth.

• The Moon's orbit would remain unchanged.

• The Moon would begin to orbit Mars instead.

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Earth's Tilt and Seasons

• Earth's seasons are caused by its 23.5-degree tilt on its axis as it orbits the Sun.

• This tilt causes different seasons.

• A hemisphere tilted toward the Sun receives more direct sunlight, which causes summer.

• A hemisphere tilted away from the Sun receives less direct sunlight, which causes winter.

Multiple Choice

What is the main reason Earth has seasons?

• The tilt of Earth's axis of rotation.

• The varying distance of the Earth from the Sun.

• The planet's rotation creating a day-night cycle.

• The Earth's orbit passing through different star systems.

Multiple Choice

How does a hemisphere's tilt toward the Sun result in the warmer temperatures of summer?

• It receives more direct sunlight.

• It is physically closer to the Sun during that time.

• It receives less direct sunlight.

• Its rotation on its axis speeds up significantly.

Multiple Choice

If Earth's axis had no tilt, what would be the most likely effect on the planet?

• Temperatures would remain relatively constant all year.

• One hemisphere would be permanently hot and the other permanently cold.

• The seasons would become much more extreme.

• The distance from the Sun would begin to cause seasons.

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What Are the Phases of the Moon?

• The phases are the different ways the Moon looks from Earth.

• They are caused by the Moon orbiting Earth and reflecting sunlight.

• The pattern goes from a New Moon to a Full Moon and back.

• Because the Moon rotates as it orbits, we always see the same side.

Multiple Choice

What are the phases of the Moon?

• The different ways the Moon appears to look from Earth

• The shadow that Earth casts upon the Moon

• The various craters and mountains on the Moon's surface

• The total number of moons that orbit the Earth

Multiple Choice

What is the primary reason why the Moon's appearance goes through phases?

• The Moon's orbit around Earth causes us to see different amounts of its sunlit side.

• Earth's shadow blocks sunlight from reaching the Moon.

• The Moon produces its own light, which changes in brightness.

• The same side of the Moon is always rotating away from Earth.

Multiple Choice

If the Moon stopped orbiting Earth but continued to reflect sunlight, what would be the most likely consequence?

• We would always see the same phase of the Moon.

• We would see the far side of the Moon for the first time.

• The Moon would appear completely dark at all times.

• The Moon would go through all its phases in 24 hours.

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Solar and Lunar Eclipses

Solar Eclipse

• The Moon passes between the Sun and Earth, casting a shadow on Earth.

• This alignment blocks the Sun's light from reaching a part of our planet.

• This can only happen during the New Moon phase when the orbits align correctly.

Lunar Eclipse

• Earth passes between the Sun and Moon, casting a shadow on the Moon.

• This event makes the Moon appear dim or take on a reddish color.

• This occurs during the Full Moon phase if the orbital alignment is just right.

Multiple Choice

What happens during a solar eclipse?

• The Moon passes between the Sun and Earth, casting a shadow on Earth.

• Earth passes between the Sun and Moon, making the Moon appear reddish.

• The Sun moves closer to Earth, blocking the Moon from view.

• Earth's atmosphere bends the Sun's light away from the Moon.

Multiple Choice

What is the primary difference in what causes a solar eclipse versus a lunar eclipse?

• A solar eclipse is caused by the Moon's shadow on Earth, while a lunar eclipse is caused by Earth's shadow on the Moon.

• A solar eclipse can only happen during the day, while a lunar eclipse can only happen at night.

• A solar eclipse makes the Sun disappear completely, while a lunar eclipse only makes the Moon look dim.

• A solar eclipse involves the Sun and Moon, while a lunar eclipse involves the Earth and Sun.

Multiple Choice

If the Moon is in its Full Moon phase, what type of eclipse could potentially occur and why?

• A lunar eclipse, because Earth can only cast its shadow on the Moon during the Full Moon phase.

• A solar eclipse, because the Moon must be full to be able to block the entire Sun.

• Either eclipse could happen, because the Moon's phase is not related to eclipses.

• No eclipse can happen, because a Full Moon means the alignment is incorrect for a shadow.

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Common Misconceptions

Misconception	Correction
Seasons are caused by Earth's changing distance from the Sun.	Seasons are caused by the tilt of Earth's axis.
The phases of the Moon are caused by Earth's shadow.	Moon phases are our view of its sunlit side as it orbits Earth.
The Moon creates its own light.	The Moon reflects sunlight back to Earth.
The Sun is on fire.	The Sun glows because of nuclear reactions in its core.

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Summary

• Gravity governs the orbits of the Sun, Earth, and Moon system.

• The Sun creates energy through nuclear reactions, not by burning.

• Earth's tilted axis causes seasons, while its atmosphere and water support life.

• The Moon's orbit causes phases and rare eclipses when perfectly aligned.

Poll

On a scale of 1-4, how confident are you about the concepts covered in today's review?

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