Phases of the Moon – Lesson Summary

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Learning Objective

In this lesson we will learn how the Moon’s appearance changes during its orbit around Earth and from different locations on Earth.

Learning Outcomes

By the end of this lesson you will be able to:

  • Explain why we see varying amounts of the Moon during its orbit around Earth.
  • Describe the four primary and four intermediates phases of the Moon and explain how they relate to the relative positions of the Moon, Earth and Sun.
  • Compare waxing and waning phases of the Moon.
  • Compare the Moon’s appearance in the northern and southern hemispheres, and at different distances from the equator.
  • Describe how the Moon rises and sets at different times.

 
phases of the moon lesson contents

(Image: Matthieu, Adobe Stock)

Lesson Topics

1 | Illumination of the Moon

2 | The Moon’s Phases

3 | The Waxing and Waning Moon

4 | Moon Phases and the Relative Positions of the Moon, Earth and Sun

5 | Moon Phases and the Hemispheres

6 | Moonrise and Moonset

7 | Movement of the Moon Across the Sky

8 | Summary

Lesson Summary

  • One half of the Moon is illuminated by the Sun at all times, but we see varying amounts of this illuminated face, known as phases, during the Moon’s orbit around Earth.
  • The lunar cycle takes approximately 29.5 days and includes eight main phases.
  • New moon – none of the Moon’s illuminated face is visible.
  • Waxing Crescent – less than one half of the Moon’s illuminated face is visible (less than one quarter of the Moon is visible).
  • First Quarter – one half of the Moon’s illuminated face is visible (one quarter of the Moon is visible).
  • Waxing Gibbous – more than one half of the Moon’s illuminated face is visible (between one quarter and one half of the Moon is visible).
  • Full Moon – all of the Moon’s illuminated face is visible (one half of the Moon is visible).
  • Waning Gibbous – more than one half of the Moon’s illuminated face is visible – the opposite side to the Waxing Gibbous Moon.
  • Third Quarter – one half of the Moon’s illuminated face is visible – the opposite side to the First Quarter Moon.
  • Waning Crescent – less than one half of the Moon’s illuminated face is visible – the opposite side to the Waxing Crescent Moon.
  • The phases of the Moon can be divided into waxing and waning phases.
  • During the waxing phases, the visible portion of the Moon is increasing.
  • During the waning phases, the visible portion of the Moon is decreasing.
  • The phases of the Moon relate to the relative positions of the Moon, Earth and Sun.
  • On the New Moon, the Moon is between Earth and the Sun.
  • On the Full Moon, Earth is between the Moon and the Sun.
  • On the First Quarter and the Third Quarter, the Moon is perpendicular to the Sun.
  • Between the First Quarter and the Third Quarter, the Moon is further from the Sun than Earth is.
  • Between the Third Quarter and the First Quarter, the Moon is closer to the Sun than Earth is.
  • The phases of the Moon appear upside-down when viewed from different hemispheres.
  • They also appear rotated by differing amounts, depending on the distance from the equator.
  • The times of moonrise and moonset vary depending on the phase of the Moon.
  • The Moon follows different paths across the sky, depending on the hemisphere, the distance from the equator, the Moon’s phase and the season.
  • Because Earth is rotating on its axis, the Moon appears to rotate as it moves across the sky.

 
plane flying past moon

(Image: IvaCastro, Pixabay)

(Header image: Delphotostock, Adobe Stock)