TRUE OR FALSE
The moon makes its own light. (Answer and explanation!)
False - it reflects sunlight.
The Moon is completely lit when viewed from Earth.
Full Moon
"The Moon changes shape throughout the month." (What's wrong with this idea?)
The shape of the Moon stays the same; its illumination is what changes.
Why can we sometimes see the Moon during the day?
It reflects sunlight and therefore is visible from Earth.
If tonight is a first-quarter moon, what phase comes next?
Waxing Gibbous
Half of the Moon is always lit by the Sun. (Answer and explanation!)
True - we may not always see the entirety of the half that is lit, but it is always lit.
Less than half of the Moon is lit, and the right side is bright.
Waxing Crescent
"Moon phases happen because clouds cover part of the Moon." (What's wrong with this idea?)
Phases are not caused by clouds, but instead by the Moon's orbit/positional change.
Why does the Moon appear to change shape?
We see different parts of the illuminated half.
A student observes the Moon losing light each night. What does this tell you about the Moon's motion in its orbit?
The Moon is waning and continuing its orbit around Earth.
We see moon phases because Earth's shadow moves across the Moon. (Answer and explanation!)
False - we see moon phases because, as the Moon orbits the Earth, different parts of it are illuminated by the Sun due to different angles/positions.
Half the moon is lit, and the left side is bright.
Third Quarter
"The Moon's phases are caused by the Moon rotating." (What's wrong with this idea?)
Phases are caused by the Moon REVOLVING or ORBITING around Earth.
Why does a new moon look dark from Earth?
The illuminated side faces the Sun, not Earth.
If the Moon looks half-lit from Earth, what must be true about the positions of the Sun, Earth, and Moon?
The Moon is at a right angle to the 'Earth-Sun line'. A 90-degree angle.
A full moon happens because the Moon is closest to Earth. (Answer and explanation!)
False - it's about position and alignment, not distance.
Thinking back to your moon reference sheet. The moon phase is in the top right corner position.
Waning Gibbous
"If we lived on a different planet, we would still see the same moon phases." (What's wrong with this idea?)
Phases depend on the observer's position; they would look much different from another planet.
Why does waxing mean "growing", even though the Moon stays the same size?
The visibly illuminated portion increases.
Two students see the Moon on the same night. One says it's waxing and the other says it's waning. What is most likely the reason for the disagreement?
They are confused about which side is illuminated or mixing up waxing and waning. Bonus Points: If you remember that the Northern and Southern Hemispheres see 'opposite' moon phases.
The Moon's phases would stay exactly the same if Earth did not rotate on its axis. (Answer and Explanation!)
True - Phases are caused by the Moon's orbit around Earth, not Earth's rotation.
The moon is in the Earth's shadow and appears totally red.
"The moon goes through phases because different parts of the Moon move into sunlight as it orbits Earth." (What's wrong with this idea?)
The Moon does not move into or out of sunlight. One half is always illuminated by the Sun, and moon phases occur because of the Moon's orbit, not because of more or less sunlight.
Why do moon phases repeat in a predictable cycle?
The moon's orbit is regular and repeats every 28 days.
The Moon's orbit stays the same, but a student claims the phases would still look the same if the Sun were moved to a different position in space. Is the student correct? Why or why not?
(If the Sun were a million more miles away, phases would not look the same even if the Moon continued its same orbit.)