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Content Benchmark E.8.B.7
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Earth Science
Atmospheric Process and Water Cycle
Solar System and Universe
Earths Composition and Structure
Content Areas
Nature of Science (NOS)
Life Science
Earth Science
Physical Science

Students know regular and predictable motions of Earth around the Sun and the Moon around Earth explain such phenomena as the day, the year, phases of the Moon, and eclipses. E/S

“Son, I can’t wait to take you up to the observatory, there will be another lunar eclipse in two days,” Wendy, an astrophysicist with NASA says. “Wow, really I can’t wait, wasn’t there a lunar eclipse not too long, ago?” asks her son, Gordon. “Yes, there was last year, but it was a total solar eclipse. Remember we had to wear special glasses to view it?” “Oh, yeah, I can’t wait to go up there with you!”

Scientists, astrophysicists, and astronomers have an important job of predicting the cycles of the seasons, moon phases, and eclipses for research, education and enthusiasts, alike. It can be an exciting experience to be able to view an eclipse, or even a blue moon in your lifetime. Scientists can predict the change of seasons, moon phases and when an eclipse will occur because they occur in cyclical patterns, which are calculated, predicted and observed by the scientific community.

Earth, a small planet in a vast universe, is the third planet from the Sun in the Solar System. Earth is a unique planet in the Solar System, in that it supports life.  The atmosphere of Earth protects the surface from extreme high and low temperatures, allowing life to flourish. Animals, plants, fungi, bacteria, and protists compose the life that is thriving on Earth’s continents and in its oceans. Earth, known as the “Blue Marble”, due to the fact that approximately 75% of Earth’s surface being covered in water, while rocky continents of diverse physiographic regions, create the remaining quarter of Earth’s surface.

Though Earth is a small planet in the Solar System, it ranks as the fifth largest planet, with a diameter of about 8,000 miles (13,000 km). Pluto, the smallest planet (now classified as a dwarf planet) in the Solar System, is one-fifth the size of Earth, while Jupiter, the largest planet, has a diameter approximately 11 times larger than Earth.  Although Earth appears round in most pictures, it is in fact not round due to its rotation. Earth is an oblate spheroid, with an equatorial diameter that is slightly larger than at the poles. The diameter of Earth at the equator is 7,926.41 miles, whereas from the North to South Pole, Earth’s diameter is 7,899.83 miles (12,713.54), a difference of 26.58 miles (42.78 kilometers). This slight difference creates a bulge at the equator, creating an imperfect sphere. 

Figure 1. Earth is known as the “Blue Marble”, due
to the vast oceans covering its surface.

Earth spins on an imaginary line, which runs from the North Pole to the South Pole, called its axis. The rotation of Earth, when viewed from above the North Pole is in a counter-clockwise direction, and this rotation causes day and night on Earth. The period of rotation of Earth is approximately 24 hours, which is known as a solar day. A sidereal day is when Earth rotates to the same position to face the same stars in the sky and this takes 23 hours and 56 minutes. The difference between a solar day and sidereal day is 4 minutes, which means a viewer will see the same stars rise above Earth’s horizon four minutes earlier each day.

Figure 2. A sidereal day lasts 23 hours and 56 minutes,
whereas a solar day lasts 24 hours.
Our calendar is based on a solar day.

To view an excellent animation of Earth’s rotation and a sidereal day, go to

Earth orbits the Sun, the center of our Solar System, in a path called a revolution. Earth revolves around the Sun at a speed of 66,700 miles (107,000 kilometers) an hour, or 18.5 miles per second. Earth’s revolution around the Sun takes 365 days 6 hours 9 minutes 9.54 seconds to travel 584 million miles around the Sun, which is known as a sidereal year. On Earth, humans use a calendar year, which is usually 365 days long, leaving 6 hours 9 minutes and 9.54 seconds, remaining each year to accumulate. To maintain alignment with the beginning dates of seasons, a leap year occurs every four years to keep seasons beginning on the same date each year. During a leap year, an extra day is added to the shortest month of the year, February, yielding 29 days.

Figure 3. A solar year occurs when Earth revolves around the Sun

Earth is tilted 23.5 degrees from the plan of the ecliptic, which creates differing amounts of incoming solar radiation (insolation) to reach Earth’s surface as the Earth progresses in its orbit around the Sun. In the Northern Hemisphere, Earth experiences winter when this hemisphere is tilted away from the Sun, resulting in indirect insolation. When, Earth moves through its orbit and approaches summer, the Northern Hemisphere of Earth is tilted towards the Sun, causing more direct insolation to reach Earth’s surface. The start of Fall and Spring are known as the Autumnal Equinox and Vernal Equinox, respectively, they occur when Earth experiences exactly 12 hours of daylight and 12 hours of night. 
The distance of Earth to the Sun doesn’t create seasons on Earth; in fact Earth is actually closer to the Sun when it is winter in the northern hemisphere than during the summer in the northern hemisphere. In winter, the distance of Earth to the Sun is 91.4 million miles (147.1 million kilometers), whereas during the summer it is 94.5 million miles (152.1 million kilometers).  The seasons are due to the tilt of the Earth.

To view a flash animation of Earth, Moon and Sun revolution relationship, go to


Figure 4. Earth’s axial tilt of 23.5 degrees causes seasons
on Earth as it revolves around the Sun.

Figure 5.
The angle of insolation and duration
of daytime heating creates seasons on Earth.

Moon Phases

The Moon is Earth’s only natural satellite. The rocky surface of the Moon is lit by the Sun as it rotates on its axis in its revolution around Earth. Observers of the Moon can view lit portions of the Moon throughout its revolution period of 27.3 days; these lit portions are known as Moon phases. The Moon phases as viewed from Earth are: 1. New Moon, 2. Waxing Crescent, 3. First Quarter, 4. Waxing Gibbous, 5. Full Moon, 6. Waning Gibbous, 7. Last Quarter, and 8. Waning Crescent. As the Moon moves between Earth and the Sun, an unlit portion of the Moon faces Earth, this is known as the New Moon phase. In this phase, the Moon is waxing, which means an observer can view more of the lit portion of the Moon with each passing day. As a portion of the moon becomes lit, the Moon is said to be a Waxing Crescent, this means that the lit portion is getting larger and larger.

After about seven days, the lit portion of the Crescent Moon has grown to the point that half of the visible moon is lit.  The Moon is approaching the First Quarter phase, where an observer can view one-quarter of the Moon being lit by the Sun.  This is where the naming of the phases becomes tricky, at any given moment an observer on Earth can only see a maximum of half the moon, the other half is never visible as it is always facing away from the Earth. So when the moon is in its First Quarter phase, an earth-bound observer see’s half of the visible portion of the moon being lit by the sun. Despite the fact that half the moon appears to be lit, it truly is only a quarter of the moon that is lit and visible from Earth, hence the name, First Quarter. Over the next seven days the lit portion of the moon continues to “wax” or grow. The moon is said to be Waxing Gibbous during this time.  Gibbous refers to the bulbous shape kind of like the belly of a pregnant woman, as time passes it gets more and more rounded. 

At approximately 14 days after the New Moon, the entire face of the moon, that is visible from the Earth, is now lit. The Moon is said to be in the Full Moon phase. As the Moon continues its orbit around Earth, observers experience the waning of the Moon, where observers view less of the Moon’s lit surface. Over the next seven days, the Moon passes through the Waning Gibbous phase until it reaches the Last Quarter phase, where, again one-quarter is lit by sunlight. Over the next seven days, the moon passes through the Waning Crescent phase where the visible portion of the moon gets smaller and smaller unlit portion of the Moon reaches its original New Moon position, where observers would not see any lit portion of the Moon.

Figure 6. Moon phases are observed on Earth as the Moon revolves around Earth.

To view a moon phase calendar, go to

Eclipses are a result of the interaction of the revolutions of Earth, Moon and Sun. Two types of eclipses can occur, Solar and Lunar. A Solar eclipse is when the Moon casts a shadow on Earth, as a result of the Moon being in between Earth and the Sun and can only occur during the New Moon Phase. A Lunar eclipse, which can only occur when the moon is in a Full Moon phase, occurs when the Moon is in the shadow, or umbra of the Earth. Solar and Lunar eclipses can be either partial or total eclipses, depending on whether the light from the sun is partially or entirely blocked. Depending on your location on Earth, you may experience a solar or lunar eclipse in your lifetime.

Figure 7. A total solar eclipse occurs when the Moon
blocks out the view of the Sun for observers on Earth

Figure 8. A lunar eclipse occurs when the Moon
passes through the shadow cast by Earth.

To view an eclipse schedule and geographic location to view an eclipse, go to

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Content Benchmark E.8.B.7
Students know regular and predictable motions of Earth around the Sun and the Moon around Earth explain such phenomena as the day, the year, phases of the Moon, and eclipses. E/S

Common misconceptions associated with this benchmark

1. Students have difficulty understanding Earth’s rotation is responsible for day and night.

Earth’s rotation on its axis causes humans to experience day and night. As Earth rotates 360° in one day, an observer on Earth would experience daylight when the sun rises on the observer’s location and the observer would experience night when the sun appears to set over the observer’s horizon. Students have trouble visualizing themselves at a fixed position on the globe as their location experiences sunrises, the sun overhead and sunsets. What is actually occurring is Earth rotating and the sun appears to move across the sky.

An excellent model and animation of Earth’s rotation is located at

A tutorial complete with an animated model of Earth’s rotation can be viewed, at

2. Students have difficulty with understanding that Earth’s distance to the Sun is not responsible for the seasons.

A common misconception when describing Earth’s motion in space is the fact that Earth’s tilt on its axis is the primary reason Earth experiences seasons. Students have difficulty understanding that Earth is actually closer to the Sun in winter than it is during summer. Therefore, the Northern Hemisphere will experience an increase in direct insolation as Earth moves from its winter position to its summer position in its orbital path. An increase in direct insolation causes higher surface temperatures for Earth’s Northern Hemisphere.

To view a model and animation of Earth’s revolution, go to

To view an informative narrated animation of Earth’s seasons and insolation, go to

3. Students have difficulty understanding apparent diameter of planets and moons.

A common misconception develops among students when teaching about solar and lunar eclipses. A solar eclipse will occur when an observer on Earth views the moon blocking out the view of the sun. Some students wonder how this could occur because of the significant size difference of Earth’s Moon and the Sun. The reason that this occurs is the result of the apparent diameter of the Moon to observers on Earth. Basically, the Moon looks bigger than it is because it is closer than the Sun to the observer. It is similar to sitting on the couch while watching a large wide screen television, and someone walks directly in front of you blocking your view of the television. It is not a result of them being wider than the television, but their body width is apparently larger than the television.

To view a diagram which models the alignment of a solar eclipse, go to

To view a schedule that displays sunrise, sunset of the Sun and Moon for your location on Earth, go to

4. Students inaccurately believe that the Moon phases are a result of Earth’s shadow on the Moon.

This is a common misconception when discussing Moon phases with students. The Moon revolves around Earth in a period of 27.3 days and an observer on Earth would view different parts of the Moon lit up by sunlight. The different parts of the Moon lit up are called phases, and an observer can view a different phase approximately every three to four days.

To view a list of common Moon misconceptions and teaching strategies intended to change the learner’s model of Moon phases, go to

To see an overview of an excellent Oreo cookie Moon Phase activity, go to

To view a calendar which provides the Moon Phase for any particular day, go to

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Content Benchmark E.8.B.7

Students know regular and predictable motions of Earth around the Sun and the Moon around Earth explain such phenomena as the day, the year, phases of the Moon, and eclipses. E/S

Sample Test Questions

1st Item Specification: Given a model, locate the position of Earth, the sun, and/or the moon that would produce a specific phase of the moon or type of eclipse, and determine the phase of the moon or types of eclipse based on the position of Earth, the sun, and the moon.

Depth of Knowledge Level 1

  1. The phases of the moon occur because
    1. the Earth creates a shadow on the moon.
    2. clouds create a shadow on the moon.
    3. an observer on Earth views the Sun lighting different parts of the moon.
    4. an observer on Earth views a shadow of the Sun on the moon.
  1. Which moon phase occurs when the Moon is directly between the Earth and the Sun?
    1. Full Moon
    2. Last Quarter
    3. New Quarter
    4. New Moon
  1. What type of eclipse will occur when the Moon completely blocks out the view of the Sun for an observer on Earth?
    1. Partial lunar eclipse
    2. Total solar eclipse
    3. Partial solar eclipse
    4. Total lunar eclipse
  1. Approximately how many days does it take for the moon to revolve around Earth?
    1. 27
    2. 39
    3. 41
    4. 50

Depth of Knowledge Level 2

  1. Which of the following explains why only small populations of humans on Earth experience a total solar eclipse?
    1. Eclipses occur on a regular basis around the world.
    2. Eclipses occur frequently around the world.
    3. Eclipses occur on an irregular basis in specific locations.
    4. Eclipses occur on a daily basis around the world.
  1. Answer the following question using the diagram below.

  1. What moon phase is shown at position 5?
    1. New Moon
    2. First Quarter
    3. Waxing Gibbous
    4. Full Moon
  1. Answer the following question using the diagram below.

  1. Approximately how many days will it take for the Moon to move in its orbit from one position to the next position?
    1. 15 days
    2. 20 days
    3. 27.3 days
    4. 4 days

2nd Item Specification: Understand that the Earth/Moon system rotates and revolves around the sun and the moon rotates and revolves around Earth in a predictable pattern

Depth of Knowledge Level 1

  1. Which of the following allows humans on Earth to experience day and night?
    1. Revolution
    2. Orbit
    3. Rotation
    4. Axis
  1. The movement of Earth around the Sun is known as a(n)
    1. revolution.
    2. rotation.
    3. axis.
    4. period.
  1. Which of the following is responsible for seasons on Earth?
    1. Earth is a shorter distance to the Sun in the summer.
    2. Earth receives direct sunlight in the winter in the Northern Hemisphere.
    3. Earth is tilted on its axis causing direct and indirect sunlight on Earth.
    4. Earth has a tilt that changes as it orbits around the Sun.

Depth of Knowledge Level 2

  1. Which statement explains why humans always see the same side of the moon?
    1. Moon revolves but does not rotate on its axis.
    2. Moon rotates but does not revolve around Earth.
    3. Moon rotates and revolves at approximately the same rate.
    4. Moon does not rotate and the Moon does not revolve.
  1. Which statement explains how the Moon and Earth are similar? The moon and Earth
    1. are entirely made of igneous rock.
    2. are covered 75% with water.
    3. rotate on its axis and revolve around a larger object.
    4. both revolve on its axis and rotate around the Sun.
  1. Answer the following question using the data table below.





4.65 billon years

4.65 billion years

Rotation Period

24 hours

27.3 days

Revolution Period

365.25 days

27.3 days

  1. Which statement is BEST supported by the information in the data table?
    1. The Moon’s revolution period is equal to its day.
    2. The Moon’s rotation period is the same as its period of revolution.
    3. The Moon takes as long to rotate on its axis as it does to revolve around the Sun.
    4. The Moon and the Earth have about the same length of day.

3rd Item Specification: Understand that our solar system is heliocentric.

Depth of Knowledge Level 1

  1. Which of the following object is at the center of our solar system?
    1. Moon  
    2. Earth
    3. Pluto     
    4. Sun
  1. What is the term used to describe the accepted theory that the Sun is at the center of our solar system?
    1. Eccentric
    2. Geocentric
    3. Heliocentric
    4. Earthcentric

Constructed Response E.8.B.7

1. Answer each of the following questions regarding a solar eclipse.

  1. Describe why a solar eclipse occurs and draw a labeled diagram of a solar eclipse including the Moon, Sun and Earth.
  1. Explain why an observer’s ability to view a total solar eclipse would depend on the observer’s location on Earth.

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Content Benchmark E.8.B.7

Students know regular and predictable motions of Earth around the Sun and the Moon around Earth explain such phenomena as the day, the year, phases of the Moon, and eclipses. E/S

Answers to Sample Test Questions

  1. C, DOK Level 1
  2. D, DOK Level 1
  3. B, DOK Level 1
  4. A, DOK Level 1
  5. C, DOK Level 2
  6. D, DOK Level 2
  7. D, DOK Level 2
  8. C, DOK Level 1
  9. A, DOK Level 1
  10. C, DOK Level 1
  11. C, DOK Level 2
  12. C, DOK Level 2
  13. B, DOK Level 2
  14. D, DOK Level 1
  15. C, DOK Level 1

Constructed Response E.8.B.7 Score Rubric:

3 points

Response addresses all parts of the question clearly and correctly.

A solar eclipse occurs when the moon blocks out the view of the Sun for viewers on Earth. Drawing should be an appropriately scaled diagram with appropriate labels. The moon should be located between the Earth and the Sun.
Because of the moon’s size, only a small amount of viewers would see an eclipse due to the small area of shadow cast on Earth.

 2 points

 Response addresses all parts of the question and includes only minor errors.

1 point

 Response does not address all parts of the question.

0 points

 Response is totally incorrect or no response provided.

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Content Benchmark E.8.B.7
Students know regular and predictable motions of Earth around the Sun and the Moon around Earth explain such phenomena as the day, the year, phases of the Moon, and eclipses. E/S

Intervention Strategies and Resources

The following is a list of intervention strategies and resources that will facilitate student understanding of this benchmark.

1. Earth in Space Demonstration

This narrated animation using provides viewers with a clear and concise example of the following concepts: rotation, revolution, moon phases and the seasons. It is an excellent resource to use for all students regardless of their developmental level. Use the pause button to take time to probe student knowledge with challenging questions, or simply have students summarize Earth in Space movements.

To access this animation, go to

2. Observing Seasons and Summer and Winter Sunlight

From Harvard University, this is a valued website by several reputable reviewers for providing an excellent guide for teaching Sun and season activities using hands-on science. The site provides clear explanations, diagrams and inquiry based questions to use throughout investigations. Some investigation titles include “Angle Spreads Sunlight, Tracking Sunrise and Sunset Times, and Measuring Earth’s Tilt.”

To access this hands-on guide, go to

3. Moon Phases with Oreos

An excellent activity for all ages, this website provides an instruction guide, template and a section provided to use to challenge students with learning Moon phases. It is an excellent way to challenge your students to create an inquiry based activity on Moon phases. Incorporate technology and have students create a movie or slideshow depicting the Moon phases using a digital camcorder or camera.

To access this lesson and template, go to

4. Lunar and Planetary Institute -Moon Phases and Seasons Misconceptions and Strategies

An invaluable resource, this website lists the most common misconceptions the public holds about Earth, Sun and Moon relationships. This is an excellent website to prepare you prior to teaching this topic. Use the links to develop strategies to change students’ misconceptions about the movements of Earth, Sun and Moon.

To access this invaluable resource, go to

5. Earth in Space – Big Kid Science

This is an excellent tutorial that provides three separate lessons on the phases of the Moon. Work through three separate animations which visually and linguistically explain the Moon phases. When done, work through six problems which test you on your knowledge about Moon phases.

To access this website, go to

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Benchmark Related Vocabulary

Phase change