Solstices and Equinoxes – Lesson Summary

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Learning Objective

In this lesson we will learn how solstices and equinoxes relate to specific points in Earth’s orbit around the sun.

Learning Outcomes

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

  • Describe what solstices are and explain how they relate to specific points in Earth’s orbit around the sun.
  • Compare the June solstice and the December solstice for the two hemispheres.
  • Compare a summer solstice and a winter solstice.
  • Describe what equinoxes are and explain how they relate to specific points in Earth’s orbit around the sun.
  • Compare the March equinox and the September equinox for the two hemispheres.
  • Compare a spring solstice and an autumn equinox.
  • Describe the five major lines of latitude and explain how they relate to solstices and/or equinoxes.

 
solstices and equinoxes lesson contents

Lesson Topics

1 | Day Length and Angle of Sunlight

2 | The Subsolar Point

3 | The June Solstice

4 | The December Solstice

5 | Between the Solstices

6 | The Equinoxes

7 | Between the Equinoxes

8 | The Five Major Lines of Latitude

9 | Summary

Lesson Summary

  • The subsolar point is the point on Earth’s surface that is directly facing the sun. At this point, the sun passes directly overhead during the day.
  • Due to Earth’s tilt, the subsolar point varies in location throughout the year, corresponding with changes in daylight length and the angle of sunlight.
  • A solstice is when one hemisphere experiences its longest day of the year while the other hemisphere experiences its shortest day of the year.
  • There are two solstices each year – the June solstice, which occurs around 21 June, and the December solstice, which occurs around 21 December.
  • The June solstice is known as the summer solstice in the northern hemisphere and as the winter solstice in the southern hemisphere.
  • The December solstice is known as the winter solstice in the northern hemisphere and as the summer solstice in the southern hemisphere.
  • An equinox is when day and night are of equal length for both hemispheres.
  • There are two equinoxes each year – the March equinox, which occurs around 21 March (midway between the December solstice and June solstice), and the September equinox, which occurs around 21 September, (midway between the June solstice and December solstice).
  • The March equinox is known as the spring equinox or vernal equinox in the northern hemisphere and as the autumn equinox or fall equinox in the southern hemisphere.
  • The September equinox is known as the autumn equinox or fall equinox in the northern hemisphere and as spring equinox or vernal equinox the in the southern hemisphere.
  • At the June solstice:
  • The subsolar point lies on the Tropic of Cancer.
  • The northern hemisphere experiences its longest day of the year and the southern hemisphere experiences its shortest day of the year.
  • The northern hemisphere is tilted directly towards the sun and the southern hemisphere is tilted directly away from the sun.
  • The sun is at its highest point above the horizon in the northern hemisphere and at its lowest point above the horizon in the southern hemisphere.
  • All latitudes north of the Arctic Circle experience 24 hours of daylight and all latitudes south of the Antarctic Circle experience 24 hours of darkness.
  • At the December solstice:
  • The subsolar point lies on the Tropic of Capricorn.
  • The northern hemisphere experiences its shortest day of the year and the southern hemisphere experiences its longest day of the year.
  • The northern hemisphere is tilted directly away from the sun and the southern hemisphere is tilted directly towards the sun.
  • The sun is at its lowest point above the horizon in the northern hemisphere and at its highest point above the horizon in the southern hemisphere.
  • All latitudes north of the Arctic Circle experience 24 hours of darkness and all latitudes south of the Antarctic Circle experience 24 hours of daylight.
  • At the equinoxes:
  • The subsolar point lies on the equator.
  • Day and night are of equal length everywhere on Earth.
  • Earth’s tilt is oriented perpendicular to the sun.

 

(Image: Volker, Adobe Stock)

(Header image: Phil, Adobe Stock)