Exploration of Shadows in the Earth, Moon, and Sun System: Moon Phases and Eclipses

Jill R. Baumtrog
Wayzata Central Middle School
Plymouth, MN
Author Profile

Summary

This is a guided inquiry in the classroom setting. Students use models of the Earth (a globe or softball), the Moon (Styrofoam ball or a ping-pong), and the Sun (desk lamp or overhead projector) to explore the interactions of shadows in the Earth, Moon, and Sun system. Students create variations of alignment with the model components to cast shadows and observe lit and non-lit portions of the Earth and Moon. Students manipulate and observe their 3-D models as they simulate the movement of these bodies through rotation and revolution. Teachers guide students to discover moon phases, lunar eclipses, and solar eclipses prior to learning about the phenomena and definitions in a traditional way. After their observations, they draw 2-D representations and develop further questions about their models and the natural phenomena.

Learning Goals

Goals -
Students will
1. model rotation of the Earth
2. model revolution of the Earth and Moon
3. manipulate models so that the Moon is between the Earth and the Sun blocking the Sun's light from reaching the surface of the Earth
4. manipulate and observe the shadow cast by the Moon covers only part of the Earth's surface
5. manipulate models so that the Earth is between the Moon and the Sun blocking the Sun's light from reaching the surface of the Moon
6. manipulate and observe the shadow cast by the Earth covers the Moon's surface
7. observe the lit and non-lit halves of the Moon as lit by the Sun
8. manipulate and observe how much of the lit portion of the Moon is visible from Earth


Skills –
1. critical thinking
2. synthesis of ideas
3. observation
4. questioning
5. modeling

Key Concepts -
1. One half of a spherical object is always lit by a light source.
2. Shadows are cast behind the object, in the opposite direction of the light source.
3. The Earth is revolving around the Sun while the Moon is revolving around the Earth.
4. The Earth rotates on its axis causing day and night.
5. The Moon's shadow cast upon the Earth is called a solar eclipse.
6. The Earth's shadow cast upon the Moon is called a lunar eclipse.
7. The amount of lit area of the Moon stays the same; the amount of the lit portion that is visible from the Earth changes.

Vocabulary Words -
1. rotation
2. revolution
3. eclipse
4. phases

Context for Use

This activity is appropriate for any Earth Science class, but is especially designed for middle school 8th grade class. This is a classroom activity. Most likely this activity would be done in a classroom with 20-30 students. Having students in groups of 2-3 is encouraged for this activity. The activity, including the modeling and questioning, can be done in one typical 50 minute class period. The materials necessary for this activity include: a student journal and pen for each student; a model Earth, Moon, and Sun (ex: softball, ping-pong, and lamp) for each group. Before this activity, students should have an emerging understand of how rotation, revolution, and the position of the Sun, Earth, and Moon can be aligned. This activity should reinforce what students have learned in previous lessons while actively exploring the concept of shadows and lit vs non-lit portions of the Earth and Moon. This activity occurs during the Astronomy unit; more specifically, it occurs when the Earth, Moon, and Sun system is discussed. This activity would not be difficult to modify for learners of different abilities, however an environment that can be dark (with the exception of the light sources (overhead projector or lamp) for each group) is ideal.

Subject: Geoscience:Lunar and Planetary Science
Resource Type: Activities:Classroom Activity, Lab Activity
Grade Level: Middle (6-8)
Theme: Teach the Earth:Course Topics:Planetary Science

Description and Teaching Materials

See the Introduction, Materials, and Content for this activity below

Introduction:
This is a guided inquiry in the classroom setting. Students use a model of the Earth, Moon, and Sun to create 3-D models. A globe or softball may be used for the Earth, a Styrofoam ball or ping-pong may be used for the Moon, and a desk lamp or overhead projector may be used for the Sun. Students create variations of alignment with the materials to cast shadows of the Moon and the Earth. Students manipulate models by revolve the Moon around the Earth. Students manipulate and observe their 3-D models as they simulate the movement of these bodies to also observe how Earth's view of the Moon's lit half changes. After their observations, they draw 2-D representations in their journals and develop further questions about their models and the natural phenomena.

Tell the students:
"How do the shadows of the Earth and Moon interact with each other? Using the materials provided, look at how and where shadows are located. What is happening with the Sun's light on the Moon? How much of the Moon is lit by the Sun? Do that change? How does the alignment of the Earth, Moon, and Sun change how much of the Moon's lit surface can be seen from Earth? Create 3-D models of different that show how the Earth, Moon, and Sun interact. Once you have explore, draw models that show the shadows, as well as the Earth, Moon, and Sun in your science journal. Draw the Moon as seen from Earth as it is at different positions around the Earth."

Materials:
- Earth globe (approximately 14"-16" in diameter) or a softball
- Styrofoam ball (approximately 3" in diameter) or a ping-pong
- Light Source (overhead projector or lamp with shade removed)
- Student journals
- Pen or pencil


Content
1. Step up the lab stations with a model of the Earth, the Moon and the Sun.
2. Have the students get into groups of 2 or 3 students.
3. Tell the students that they will be looking at how the positions of the Earth, Moon and Sun interact.
4. How do the shadows of the Earth and Moon interact with each other? Using the materials provided, look at how and where shadows are located.
4. How does the view of the Moon's lit and non-lit areas change as viewed from Earth?
6. Manipulate 3-D models of different that show how the Earth, Moon, and Sun interact.
7. Once you have explored, draw models that show the shadows, as well as the Earth, Moon, and Sun in your science journal.
8. Once you have explored, draw diagrams of the Moon (as viewed from Earth) shading in the lit and non-lit sides of the Moon in your science journal.
9. Write down any questions you have about what you have observed or about the Earth, Moon, and Sun system.
10. Have the students turn on their lamps while you turn off the classroom lights to make the shadow more visible.
11. Give the students time to play with the objects and shadows.
12. Possible points to elicit for the students during the exploration:
1. Does the Sun have a shadow?
2. What happens when the Moon is between the Earth and the Sun?
3. What happens when the Earth is between the Moon and the Sun?
4. Where do the Earth's shadows go?
5. Where do the Moon's shadows go?
6. How does the Earth move in relation to the Sun?
7. How does the Moon move in relation to the Earth?
8. How is day and night created?
9. How much of the Moon is lit by the Sun?
10. Does Earth's view of the Moon change?
11. Is the Earth's shadow on the Moon at all times? When?
13. After students have explored, have the students:
1. Draw models in their science journals that show shadows, as well as the Earth, Moon, and Sun.
2. Draw diagrams of the Moon as viewed from Earth as the Moon revolves around the Earth.
3. Have them label their drawings.
4. Have students generate questions they still have about the phenomena.
14. Discussion:
1. What did you observe when creating your 3-D models?
2. How do the shadows of the Earth and the Moon interact with each other?
3. What do we call it when a shadow lands on another object?
4. How could you describe the processes you saw of the Earth and Moon shadows to a 3rd grader?
5. How does Earth's view of the Moon change over time?
6. How could you describe the processes you saw of the lit vs non-lit portions of the Moon to a 3rd grader?
15. Science Journals (assessment):
1. Create diagrams that vary the position of the Earth, Moon, and Sun so that the shadows of the Earth affect the Moon, and the shadows of the Moon affect the Earth. Label the diagrams.
2. Create diagrams of the views of the Moon from Earth at different times of the Moon's revolution around the Earth.
3. Write a description of the processes that occur for each of both of the two situations above. Explain the events in detail so that a 3rd grader would understand the concepts.
4. Have students generate questions they still have about the phenomena.

Teaching Notes and Tips

Areas of Confusion/Misconceptions:
- The Sun does not have a shadow.
- The Moon's shadow is smaller than the Earth.
- The Earth's shadow is larger than the Moon.
- The New Moon is visible during the day.
- The Sun's light is blocked by the moon during the middle of the day.
- The Earth's shadow does not create the phases of the Moon.
- The Moon is always half lit by the Sun.
- The amount of the lit portion of the Moon remains the same but the amount that is seen from Earth changes.

Tips
- Shutting off the classroom lights will help students see shadows.
- Having the lamps (or overhead projectors) spaced apart will help prevent shadows from other directions.
- Allow students to explore the shadow concepts, but reinforce and guide struggling to being looking for shadows as they cast on other objects.

This activity is different from what I've had my students do in the past. Usually I have just done this activity with the same materials to explore Moon Phases. However, when I get to teaching about eclipses, the students usually look at diagrams and video clips, rather than do any 3-D modeling themselves. This will hopefully engage them more and help them conceptually understand the phenomena before I show them real footage of eclipses from Earth, diagrams of the eclipses from space, views of the Moon phases from Earth, and diagrams of the Moon as it revolves around the Earth from space vantage point.

Assessment

Students successfully achieve the goals if their journals demonstrate the following items through diagrams and descriptions:

STUDENT WORK – To be done in their science journals:
- Sketches of Earth, Moon, and Sun with shadows (all labeled) after initial exploration
- List of Student Questions
- Sketches of diagrams of Earth, Moon, and Sun with the center object being the Earth in one diagram and the Moon being the center object in the other diagram; shadows are also drawn
- Description that has an explanation of shadows and the Earth, Moon, Sun alignment that are appropriate and understandable for a 3rd grader
- Sketches of diagrams of the Moon as viewed from Earth that detail the lit and non-lit portions of the Moon
- Description that has an explanation of how the Moon revolves around the Earth cause the Earth to see different amounts of the lit portion of the Moon is appropriate and understandable for a 3rd grader

It is up to the instructor to determine what other assessment or conclusions the students may do in conjunction with Moon Phases and Eclipses.

Standards

Grade 8

Strand 3. Earth and Space Science

Sub-Strand 3. The Universe

Standard 1. The Earth is the third planet from the sun in a system that includes the moon, the sun, seven other planets and their moons, and smaller objects.

Code 8.3.3.1.5

Benchmark Use the predictability of the motions of the Earth, sun and moon to explain day length, the phases of the moon, and eclipses.

References and Resources