Phases of the Moon Exercise
In this exercise, you will investigate the cause of the phases of the Moon. The figure
below shows an orbital diagram of the Earth-Moon system as viewed from above the
Earth's North Pole. Light from the Sun is coming from the left. Note that the drawing is
not to scale.
Visit the following Website for more information:
http://astro.unl.edu/naap/lps/animations/lps.html
Section I
Shade in the part of the Moon that is in shadow and the part that is unobservable from
Earth in each of the eight numbered positions. The first has been completed as an
example. (Use dark shading for the shadow, light cross-hatch for the unobservable side.)
Section II
Record the phase and appearance of the Moon in Table 1 for each of the eight positions
in the diagram. (Again, the first has been done as an example.) Also determine the
Moon's elongation. Note that if you know the Moon's elongation, you know its phase,
and vice versa.
Position 1
Position 2
Position 3
Position 4
Position 6
Position 7
Position 8
waxing
crescent
45°
Position 5
Section III
Use the diagram to fill in the missing data.
Phase of Moon
Time of Day
Moon's Position in Sky
00:00 (midnight)
rising in the East
15° above Western horizon
waning crescent
waxing gibbous
20:00
12:00 (noon)
directly overhead