Astronomy
Unit / Moon Phases
Enduring Understanding / Past, present, and future observations of all of the objects in the celestial sphere have and will continue to establish an understanding of the properties and motions of astronomical objects, astronomical events, and the physical phenomena that continually affect the Earth
SOL Objectives / SOL 3.8 - The student will investigate and understand basic patterns and cycles occurring in nature.
a) patterns of natural events such as day and night, seasonal changes, simple phases of the moon, and tides;
Title / Moon Phases
Lesson Objective / Using inexpensive tools and simple geometry, students can figure out the cause of the phases of the moon, and solar and lunar eclipses.
Inquiry Level / Level 2 – Questions and methods given, solution open
Materials Required /
- Styrofoam balls (5 cm in diameter) – enough for each student
- Pushpin with nub for holding – one per Styrofoam ball
- A lamp with an unfrosted bulb
Phases of the Moon – Teacher Instructions
Setup
Ask students to carefully push the pushpin into the Styrofoam ball. Explain that each Styrofoam ball is a moon. Her/his arm is the earth-moon respective gravity and is not at the proper distance since her/his head sets the scale of the earth. The earth-moon distance is approximately 30 times the diameter of the Earth-Moon distance.[1]
In a large dark room, have students spread out so that they are more than arms-length away from any other student and not in someone else’s line of sight to thelight bulb/”Sun.”
Pre-questions:
Q. When looking at the sun, which direction does the moon orbit the earth?
A. The moon orbits from west to east.We see the moon “moving” from east to west because of the rotation of the earth on its axis is faster than the ~28 day orbital cycle of the moon around the earth.
To Do and Notice
The teacher turns on the lamp and darkens the room.
Hold the Styrofoam ball by its pushpin just to the left of the line between you and the lamp.
What do you see?
Notice that you see an illuminated crescent moon. This is the waxing crescent. We know this because the moon orbits the earth from west to east so it will be gaining light. Continue to experiment with your moon’s exposure to light from your perspective and fill in your table.
Properties of the Moon Lab
Pre-lab Questions
For each question below, answer in complete sentences.
- What causes the different phases of the moon?
- What is an eclipse? List the different types of eclipses.
- Do all parts of the moon experience direct sunlight?
Lab
Part 1 – Phases of the Moon
- Completethe diagram below—which is not to scale—showing your moon, the sun, and the shadow that an observer on the earth would see. Be sure to shade in the shadows.
“Overhead” view
/ What does the moon look like in the sky? That is, draw the phase that we would see.
- Continue rotating to your left (East) until you see your moon half illuminated.
- How much of the moon is illuminated in total?
- How much of the moon is illuminated from your perspective?
- Which phase of the moon is this?
- Draw a new diagram similar to #1 for the new earth-moon-sun arrangement.
“Overhead” view
/ What does the moon look like in the sky? That is, draw the phase that we would see.
- What seems to cause the patterns of light and dark on the moon?
- Now continue rotating in the same direction. At which point do you get a waxing gibbous?
“Overhead” view
/ What does the moon look like in the sky? That is, draw the phase that we would see.
- Continue rotating to the position where you expect a full moon.
- If you don’t see the moon fully illuminated, what could be a possible cause?
- Complete the following diagram for a full moon.
“Overhead” view
/ What does the moon look like in the sky? That is, draw the phase that we would see.
- Continue rotating past the full moon. What is happening to your shadow?
Part 2 – Eclipses
- Where in the moon’s orbit around the earth can the moon cast a shadow on the earth? From the earth’s perspective, what is being blocked? Draw a diagram to aid in your explanation.
- Where in the moon’s orbit can the moon go into the shadow of the earth? What type of eclipse is this?
- Knowing that the orbit of the moon is inclined 5 from the ecliptic, explain why eclipses do not occur every new or full moon.
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