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Earth, Moon, and the Sun

The longest and shortest days

Some days are long and some are short. One day a year is the longest. One day a year is the shortest.

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The idea

One year in the north.
Step 1 of 4
  1. One year in the north.
  2. The longest day is the summer solstice.
  3. The shortest day is the winter solstice.
  4. Day and night are about equal on the two equinoxes.

In the north, the longest day is near 21 June. The shortest is near 22 December.

Near 21 June, the north leans most toward the Sun. So that day is the longest. Near 22 December, the north leans most away. So that day is the shortest.

The equinoxes fall near 21 March and 23 September.

The equator is the line round Earth's middle.

Near the equator, the day stays about 12 hours all year. At the North Pole, the Sun is up all day in June.

Jump to lesson

This track

  1. 0 Start here
  2. 1 Earth is doing two things at once
  3. 2 The Moon keeps one face turned to us
  4. 3 When three line up, one shades another
  5. 4 The Moon shades a patch of Earth
  6. 5 Earth shades the Moon
  7. 6 Why it is not every month
  8. 7 One is safe to watch, the other never is
  9. 8 Checkpoint: motions, the Moon and eclipses
  10. 9 Why the Sun seems to move
  11. 10 Day here, night there
  12. 11 The star that stays still
  13. 12 Checkpoint: the turning sky
  14. 13 The night sky changes through the year
  15. 14 The tilt makes the seasons
  16. 15 The longest and shortest days
  17. 16 Checkpoint: the year, the tilt and the seasons
  18. 17 The big picture
  19. 18 Track quiz

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