Moon Phases
What is the phase of the Moon when the entire side facing Earth is illuminated?
Full Moon
Why is half of the Moon always illuminated by the Sun?
The Moon reflects sunlight, and one side always faces the Sun.
Why does the Moon appear to grow larger (waxing) during certain periods?
The illuminated part visible from Earth is increasing as the Moon orbits.
Which of the following conditions is required for a lunar eclipse to occur?
The Earth must be directly between the Sun and the Moon.
Why can’t we see the Moon during the new moon phase?
During the new moon, the side of the Moon illuminated by the Sun is facing away from Earth, so we only see the dark side of the Moon. Therefore, it is not visible in the night sky.
During which phase of the Moon can a solar eclipse occur?
New Moon
If you are observing the Moon from Earth and see only a thin crescent of light, what is happening in space?
You are seeing only a small part of the illuminated side.
You observe the Moon over several nights and notice that the light part is shrinking. What phase is this, and why is it happening?
Waning, because the illuminated portion visible from Earth is decreasing as the Moon moves
What happens during a lunar eclipse?
The Moon moves into Earth’s shadow, becoming dark.
If someone says, "The Moon is half-lit during every phase," would that be correct? Explain why or why not.
No, this statement is incorrect in terms of what we see. Although half of the Moon is always illuminated by the Sun, the portion of the illuminated half that is visible from Earth changes. During the new moon, none of the illuminated half is visible, while during a full moon, all of it is visible.
Which phase of the Moon follows the first quarter?
Waxing Gibbous
The Earth completes one full rotation on its axis every ___ hours.
24 hours
The moon is always visible
No the moon is not always visible
The Moon always shows the same face to Earth.
True
Imagine you see a full moon. Two weeks later, you see a new moon. Describe what happened to the Moon’s position and visibility during this time.
Over the two weeks, the Moon has moved from a position opposite the Sun (full moon) to a position between the Earth and Sun (new moon). During this period, the illuminated part visible from Earth has gradually decreased through the waning gibbous, third quarter, and waning crescent phases.
Which phase of the Moon occurs when none of the illuminated part of the Moon is visible from Earth?
New Moon
The Sun is a giant ball of gas composed mostly of ___ and ___.
Hydrogen and Helium
Half of the moon is always dark
Incorrect, Half of the moon is always illuminated
A student says, "The Moon changes its shape as it orbits Earth." Is this statement true or false? Explain why the Moon’s shape appears to change when observed from Earth.
False. The Moon does not change shape; it only appears to change due to the angle at which sunlight hits it and how much of the illuminated side we can see from Earth. This creates the illusion of changing shapes, which we call phases.
How long does it take the Moon to orbit the Earth?
One Month
Why can we see different phases of the Moon?
The position of the Moon in relation to Earth and the Sun causes different amounts of the lit portion to be visible from Earth.
The force that keeps the Earth in orbit around the Sun is ___.
Gravity
How would the length of a day on Earth be affected if the planet’s rotation were slower?
If Earth’s rotation were slower, the length of a day would be longer, meaning we would have more hours of daylight and nighttime. This could affect the climate and life on Earth.
Explain why we sometimes see a full moon, and other times only a part of the moon. Include in your answer how the positions of the Earth, Moon, and Sun affect this.
We see a full moon when the Earth is between the Moon and the Sun, allowing the entire illuminated side of the Moon to be visible. At other times, depending on the Moon’s position in its orbit, only part of the illuminated side is visible, which is why we see phases like crescents or quarters.
How would life on Earth be different if the Moon did not exist?
Without the Moon, Earth would have much smaller tidal changes, potentially affecting marine life. The Moon also stabilizes Earth's axial tilt, so without it, Earth's tilt could fluctuate more, leading to extreme climate variations.