日本語

Sundials

Making a Sundial on the North Pole
  • If we made the earth’s axis the rod for a sundial at the North Pole, the shadow cast by the rod would move 15 degrees every hour. This is because the earth rotates full circle once every day, 360 degrees ÷ 24 hours = 15 degrees (1 hour) which means that the Earth rotates 15 degrees every hour.
    If the sundial’s rod is the earth’s axis, the clock face would be parallel to the equator. All of you, too, can make your own sundial by making the clock face parallel to the equator where you are!
    If we made the earth’s axis the rod for a sundial at the North Pole, the shadow cast by the rod would move 15 degrees every hour. This is because the earth rotates full circle once every day, 360 degrees ÷ 24 hours = 15 degrees (1 hour) which means that the Earth rotates 15 degrees every hour.　If the sundial’s rod is the earth’s axis, the clock face would be parallel to the equator. All of you, too, can make your own sundial by making the clock face parallel to the equator where you are!
  • I wonder how we can make one…
  • We can make our own sundial!
  • I wonder how we can make one…　We can make our own sundial!
Making Your Own Sundial Where You Are Enlarge
Enlarged diagram
If you set the axis of your sundial to be be same angle as the latitude of the place where you are, then the clock face will be parallel with the equator. By doing this, you can make an accurate sundial.
  • You understood how sundials work, right? OK then! Now let’s try making a fun sundial like the one shown in the photograph.
  • I’m going to make a fun clock too!　If you’ve already made one, that means you’ve understood how sundials work! Good job!
Go back to the beginning

About Sundials

Go back to the beginning

  • The Sun and the Earth:Earth’s Rotation and Revolution
  • The Sun and the Earth:Summer and Winter Solstices
  • The Sun and the Earth:Latitude and Longitude
  • Sundials