Learning Lesson: Moonlight Serenade

Overview

We observe the different angles between the sun, earth and moon by the phases of the moon we see each month. Students, acting as the earth, will see differences in light and dark sides of their hand-held moon.

TOTAL TIME	10 minutes
SUPPLIES	Table lamp (or another light source) for class. (A clear light bulb will work better than a frosted bulb.); Per pair of students: pencil; white Styrofoam ball (approximately two to three inches in diameter).
PRINTED/AV MATERIAL	Observation form (pdf)
TEACHER PREPARATION	A room that can be darkened.
SAFETY FOCUS	Rip Currents

Procedure

1. Divide the students into pairs and distribute one observation form to each student.
2. Place a lamp on a table or desk and remove the shade. Turn the lamp on.
3. Stick the Styrofoam ball on the pencil.
4. Darken the room.
5. Have one of the pair of students hold the ball, by the pencil, at arms length blocking out the light from the lamp. Explain they represent the earth, the ball is the moon, and the lamp is the sun.
6. Comparing the light and dark side of the ball, on the observation form, under the "View from Earth" column, have that person draw/shade what their "moon" looks like. Have the student label this as "New Moon".
7. Have the other person mark the location of the moon relative to the earth and sun on the dotted line (representing the Moon's orbit) under the "Position in Space" column.
8. Have the student holding the "Moon" rotate 45° counter-clockwise. Repeat steps 6 and 7. Label this as "Waxing Crescent".
9. Rotate another 45°. Repeat steps 6 and 7. Label this as "First Quarter".
10. Repeat steps 6 and 7 for each additional 45°, labeling them as "Waxing Gibbous", "Full Moon", "Waning Gibbous", "Last Quarter", and "Waning Crescent" respectfully.
11. Have the students switch positions and repeat the process again.

Discussion

Each student will see their "moon" from two vantages points; from Earth and from "space". They should quickly observe the orbit of the Moon is the reason for the various phases of the moon.

They will also observe the phenomena of eclipses at New and Full Moon positions. At "New Moon", when the Moon is between the Earth and Sun, the Moon will block the Sun's light onto the Earth, called a solar eclipse. At "Full Moon", the Earth blocks light from reaching the moon. This is called a lunar eclipse.

Explain that since the Moon's orbit is inclined to the Earth's equator that direct alignment of Earth, Moon and Sun occurs typically twice a year, six months apart. The remaining times, the Moon's orbit is positioned either above or below the shadow cast by the Earth.

Also, as the Moon orbits the Earth, its tidal pull also moves around the Earth. As a result, the times of high and low tides changes each day.

When the Moon, Earth and Sun are inline (twice a month), the tidal pull by the Moon and Sun are at their greatest producing "Spring Tides", where the difference in height between the daily high and low tide are at their greatest.

When the Earth, Moon and Sun are at right angles to each other (also twice a month), the difference in height between the daily high and low tides are at their least, called "Neap Tides". The "Spring Tide or Neap Tide" wheel (above right)(below) can be printed and cut-out to help illustrate how the orbit of the moon affects the spring and neap tides.