Name
Date
Our Changing Moon
By Cindy Grigg
Photo credit: NASA
Sometimes the moon looks like a round, shiny coin in the sky.
Sometimes it's a thin, silvery sliver that looks like something took a
bite out of it! What causes the moon to look so different at different
times?
When we see the moon shining, we are seeing sunlight reflecting
from the moon's surface. The part of the moon that is lit up changes as
the moon moves around Earth and Earth moves around the sun. We
call these changes phases of the moon. These are the moon's phases:
new moon, waxing crescent, first quarter, waxing gibbous, full moon,
waning gibbous, third quarter, waning crescent, and back to new moon.
New Moon For a few days each month, we can't see the moon. This happens when the moon, the Earth, and
the sun are lined up in space. The moon is between the Earth and the sun. The far side of the moon, the side that
faces away from Earth, is in full sunlight. The side we see is in full shadow. We call this the new moon phase.
The new moon rises in the east at the same time as the sun. It sets in the west at the same time as the sun, too.
Waxing Crescent
As the moon moves along its path around the Earth, it is no longer in between Earth and
the sun. At first, just a little of the side of the moon we see is not in shadow. We see a thin crescent. We say the
moon is waxing when the lighted part is growing larger.
First Quarter When we see half of the moon's circle lit, we call it the first quarter. The moon is one-quarter
of its way through its monthly phases. The moon has moved one-quarter of the way around the Earth. This
happens about one week after the new moon phase. It may seem confusing, but just remember that the quarter
moon looks like a half-circle. We are seeing one-quarter of the whole sphere of the moon. Seen from the Northern
Hemisphere, it is shaped like the bottom half of the lower-case letter "b." The right side is lit. The first quarter
moon rises around noontime and sets around midnight. Around sunset, then, the first quarter moon is high in the
sky.
Waxing Gibbous The roving moon continues on its trip around the Earth. It is still waxing; it looks as
though it is growing larger. More of the side of the moon we see is moving into sunlight. When more than half
the moon is lit, we call it a waxing gibbous moon.
Full Moon Halfway around its orbit from where it started as a new moon, the entire side of the moon facing
Earth is in sunlight. This is the full moon. This happens about two weeks after the new moon. In space, the moon
is opposite the sun. Earth is in between the two. The full moon rises at about the same time the sun sets. The full
moon sets at about the same time the sun rises.
Waning Gibbous As the moon continues its journey, we see less of the sunlit side and more of the side that
is shadowed. When the moon looks as though it is growing smaller, we say it is waning. When it is less than a full
moon but more than a quarter moon (more than half the circle is lit), we call it a waning gibbous moon.
Last (or Third) Quarter When half the moon's circle is lit as it is growing smaller, it is three-fourths of its
way around the Earth. So it is called the third quarter or last quarter phase. We are seeing half of the sunlit side of
the moon. Seen from the Northern Hemisphere, it is shaped like the bottom half of the lower-case letter "d." The
left side is lit. The third quarter moon rises about midnight and sets at around noontime. It is high in the sky at
sunrise.
Waning Crescent The moon continues on its orbit. Then a larger piece of the moon's surface is in shadow.
The lighted part is growing smaller and smaller, and we call it a waning crescent moon. Soon, it is completely in
Name
Date
shadow. It is in the new moon phase, back where it started in its orbit one month ago.
The time it takes the moon to go from one new moon phase to the next takes about twenty-nine and one-half
days. We call this a lunar month. Luna was the Latin word for moon. And our word "month" comes from the
word "moon." The moon rises and sets about fifty minutes later each day.
Rising and Setting The time of moon rise and set is tied to the four main moon phases. At new moon, the
moon rises and sets with the sun. At first quarter, the moon rises around noontime and sets around midnight. At
full moon, the moon rises at sunset and sets at sunrise. At last quarter, the moon rises about midnight and sets at
around noontime.
As the moon orbits Earth and Earth orbits the sun, the sun lights the moon from different angles. The moon's
shape appears to change throughout the month. The phase of the moon that we see depends on how much of the
sunlit part of the moon that we can see. The lighted part we see depends on the positions of the Earth, moon, and
sun. The time of night or day that we can see the moon also changes.
Our Changing Moon
Questions
1. Where does moonlight come from?
A. the sea
B. the sun
C. outside the solar system
D. the Earth
2. Sometimes the moon looks like a round, shiny coin in the sky. The moon is compared to a coin. This
sentence is ______.
A. a simile
B. alliteration
C. a metaphor
D. onomatopoeia
3. When we can't see the moon in a clear nighttime sky, it is most likely in its ______ phase.
A. new moon
B. full moon
C. crescent
D. waxing
4. At about what time does a full moon rise?
5. You see the moon at three o'clock in the afternoon. Which phase is it in?
A. first quarter
B. new moon
C. full moon
D. last quarter
Name
Date
6. What do you think was the author's purpose for writing the last paragraph of this story?
A. to summarize the story's main ideas
B. to share personal feelings about the moon
C. to inform readers about the new moon phase
D. to persuade readers that they should understand the moon's phases
7. Why do you think the author used bold headings for some paragraphs?
A. Bold headings help readers find key details.
B. In this story, bold headings help readers know the sequence of the moon's phases.
C. In this story, bold headings help readers understand what the author is describing.
D. all of the above
8. Here are the moon's phases, but they are not in the correct order: first quarter, third quarter, new moon,
waxing crescent, waning crescent, full moon, waxing gibbous, waning gibbous Put them in the correct
order starting with waxing crescent.
Watch the moon for a month. Keep a journal of your observations. Draw a picture of the moon that you see
each night. Record the times of moon rise and moon set. There will be times when you will not see the moon;
record them. At the end of the month, write a summary of your observations. Share them with your class.
Name
Date
Write a story using personification. In your story, the moon should become like a person in some way. Have the
moon tell your story.