6 The Moon

Formative Assessment: The Moon & Stars Phases of the Moon

The Moon orbits around Earth once every 28 days, or about once a month. Depending on where the Moon is in its orbit, it appears different from Earth. However, everyone on Earth sees the same phase of the Moon on the same day.

The phases of the moon are:

  • New: The Moon’s face is not visible from Earth
  • Crescent: Between a new moon and a quarter moon
  • Quarter: From Earth, we can see half of the moon’s face which is a quarter of the entire moon
  • Gibbous: Between a quarter moon and a full moon
  • Full: All of the Moon’s face is visible from Earth

For the first half of this cycle, the visible part of the Moon waxes or grows larger. After reaching a full moon, the Moon wanes or grows smaller for the second of the cycle.

The image, below, shows the Moon’s phases.

K-6 Standards

1-ESS1-1. Use observations of the sun, moon, and stars to describe patterns that can be






Moon Phases from Earth” by pmonaghan is licensed under CC-By-NC-ND 2.0


Where are the Moon, Sun, and Earth in relation to each other for the different Moon phases?



For further explanation of the Moon’s phases, watch the following video.

Video credit: “The Moon” by Khan Academy is licensed under CC BY-NC-SA 3.0. Note: All Khan Academy content is available for free at khanacademy.org.


Characteristics of the Moon

  • Distance from Earth: 239,000 miles
  • Size: As seen in the image, below, the Moon is about 1/4 the size of Earth.
The Earth and the moon with their size at the exact same scale” by Lsmpascal
Own work is licensed under CC BY-SA 3.0.
  • Composition:
    • Very similar to Earth
    • Has an iron , , and
  • Surface: The Moon’s rocky surface is covered in dormant volcanoes and which are the results of impacts from and over billions of years. The Moon is covered with craters for two reasons:
    1. It does not have an atmosphere to protect it from the impact of objects such as asteroids in space.
    2. There is no wind on the Moon to existing craters.
  • Climate: The Moon has no atmosphere, wind, or weather. Thus, the temperature can range from extremely hot to extremely cold since there is no atmosphere to protect it from the Sun’s heat or insulate the surface.
  • Gravity: Remember, more mass=more gravity and less mass=less gravity. As such, the Moon has 1/6 of the gravity of Earth. This means if you weigh 60 lbs on Earth, you would weigh 10 lbs on the Moon.
    • The Moon’s gravity, although weaker than Earth’s gravity, has enough pull to move water. This is what causes tides on Earth. As Earth rotates on its axis, the area on the near side of the Moon feels its gravity. As seen in the image below, this causes the water on that side–as well as the opposite side of Earth–to bulge out and create a high tide. As Earth continues to rotate, the gravitational pull weakens and the water recedes, creating a low tide. Since Earth completes one full rotation on its axis each day, most areas have two high tides and two low tides per day.
Tidal Force” by NOAA SciJinks is public domain

Sides of the Moon

There are two sides of the moon: the near side (the side we can see from Earth) and the far side (also known as the dark side). The Moon does not create its own light; it gets light from the Sun. As such, the dark side is not actually dark–it is just called the dark side because we cannot see it from Earth.

The near side of the Moon (left) vs. the far side of the Moon (right). Image credit: Near and far side of the moon by NASA

Since Earth has a larger mass, it exerts a stronger gravitational pull on the Moon. Earth’s pull controls the Moon’s orbit so that the Moon rotates once on its axis in the same amount of time it takes to orbit Earth. Therefore, the same side of the Moon is always facing Earth and we have a near side and a dark side. This effect is called tidal locking.

Click this link to see an animation of how tidal locking works as the Moon orbits Earth.

Nearside of the Moon Farside of the Moon
  • The side we can see from Earth
  • Not visible from Earth
  • Thinner crust: The Moon was in a molten state when it was first created. This side of the Moon is closer to Earth, so it received more heat and cooled off more slowly.
  • Thicker crust: This side of the Moon is farther from Earth, so it received less heat and cooled more quickly.
  • Large dark spots called maria (singular is “mare”) were formed from ancient volcanic eruptions. The leftover basalt rock spread out and cooled forming the maria. Early astronomers thought these dark spots were actual seas and thus used the word mare which is Latin for sea.
  • Rugged and marked with many small craters as a result of impacts from space debris.

Sputnik and the Space Race

On October 4th, 1957 the Soviet Union successfully launched Sputnik, the world’s first artificial satellite, into Earth’s orbit.  This successful launch of Sputnik sparked the Space Race between the Soviet Union and the United States. These two countries competed to get the first human to land on the Moon.

On January 31, 1958, the United States launched Explorer 1, a satellite that discovered the magnetic radiation belts around Earth. That same year, the United States created the National Aeronautics and Space Administration (NASA). In 1959, the Soviet Union launched Luna 2, the first spacecraft to land on the Moon. In April 1961, the Soviet astronaut Yuri Gagarin became the first person in space when he orbited Earth. Shortly after, astronaut Alan Shepard became the first American in space in May 1961.

The Space Race heated up and President John F. Kennedy claimed that the United States would put a man on the Moon before the end of the decade. In 1962, American astronaut John Glenn successfully orbited the Earth. In 1968, American mission Apollo 8 orbited the Moon. Finally, in 1969, the American mission Apollo 11 successfully landed the first two people on the Moon: astronauts Neil Armstrong and Buzz Aldrin.

Interesting Fact

Dr. James Van Allen from the University of Iowa created the radiation detector that launched on the Explorer 1 satellite. This led to the discovery of magnetic radiation belts around Earth which are known as Van Allen radiation belts in his honor. Van Allen Hall on Iowa’s campus is also named after him.

Women and Space

Traditionally, the story of the Space Race features male scientists and astronauts. However, women have played a key role in the history of American space exploration. NASA mathematicians Katherine Johnson and Dorothy Vaughan along with engineer Mary Jackson were key members of the team that launched John Glenn into space in 1962. In addition to this mission, these women had long careers at NASA. Their stories have recently been popularized in the movie Hidden Figures.

Katherine Johnson by NASA
Mary Jackson by NASA
Dorothy Vaughan by NASA

Initially, women were seen to have a physical advantage as astronauts; they tend to be lighter, shorter, and consume less food. In 1960, astronaut Jerrie Cobb had logged twice as many flying hours as John Glenn. But NASA made a requirement that astronauts had to be military pilots, a job only men could have. A group of 13 female astronauts, including Cobb, was gathered and subjected to the same tests as the male astronauts. The women passed all of the tests, and in many cases, performed better than the men. Still, NASA refused to support the female astronauts. In 1983, Sally Ride became the first female astronaut in space.


Sally Ride by NASA
Jerrie Cobb by SDASM Archives












Performance Expectations

1-ESS1-1. Use observations of the sun, moon, and stars to describe patterns that can be predicted. [Clarification Statement: Examples of patterns could include that the sun and moon appear to rise in one part of the sky, move across the sky, and set; and stars other than our sun are visible at night but not during the day.] [Assessment Boundary: Assessment of star patterns is limited to stars being seen at night and not during the day.]
MS-ESS1-1. Develop and use a model of the Earth-sun-moon system to describe the cyclic patterns of lunar phases, eclipses of the sun and moon, and seasons.  [Clarification Statement: Examples of models can be physical, graphical, or conceptual.]



First Grade

ESS1.A: The Universe and its Stars


Fifth Grade


ESS1.B: Earth and the Solar System

Middle School

ESS1.A: The Universe and Its Stars

ESS1.B: Earth and the Solar System


Crosscutting Concepts


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            Connections to Nature of Science


Scientific Knowledge Assumes an Order and Consistency in Natural Systems

  • Science assumes natural events happen today as they happened in the past. (1-ESS1-1)
  • Many events are repeated. (1-ESS1-1)

Lesson ideas:

Take children outside to see the Moon in the daytime. Show them how to observe the Moon, and keep a Moon journal, and encoruage them to look for the Moon day and night. Look at your Moon journal to see what the patterns are.

Try to recreate what they see outside with the Earth Sun Moon system.