Moon Phases — Reading Comprehension Lesson

Reading Passage

Moon Phases

The moon is Earth’s only natural satellite. It orbits Earth once about every 29.5 days. As the moon travels around Earth, different amounts of its sunlit surface are visible from Earth. These changing views of the moon are called phases. The moon does not change shape — only the amount of the lit side that we can see changes as the moon moves through its orbit.

The moon cycle begins with the new moon phase. During a new moon, the moon is between Earth and the sun. The lit side of the moon faces away from Earth, so we cannot see the moon in the night sky. As the moon continues its orbit, we begin to see a small sliver of the lit side. This growing crescent is called the waxing crescent phase.

About a week after the new moon, we can see exactly half of the moon’s sunlit surface. This is called the first quarter moon. The moon continues to grow, or wax, until we see the full moon — the phase when the entire sunlit face of the moon is visible from Earth. A full moon occurs about 14 to 15 days after a new moon.

After the full moon, the amount of the lit side we can see begins to decrease. This shrinking is called waning. We see the waning gibbous phase, then the third quarter moon, and finally the waning crescent. The cycle ends when the moon returns to the new moon phase and the cycle begins again. Each complete cycle takes about a month, which is where the word ‘month’ comes from.

The phases of the moon have been important to humans throughout history. Ancient people used the lunar cycle as a calendar to track time and plan planting seasons. Today we understand that the moon’s phases are caused by its orbit around Earth and the angle at which sunlight hits its surface. Lunar calendars are still used in many cultures around the world for religious and cultural events.

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