Hi Roger and Mitchael, I'm sure others have thought of and have used these concepts before us. Sundials have been around for a long time.
What these concepts achieves are: That all clocks have a energy source to make them work. For sundials it is the rotation of Earth. And that planet Earth rotates (moves) in relation to the sun. It is not the sun that moves. We often say that the sun moves across the sky. But it is planet Earth that rotates and moves. This is important to be able to fully understand how a sundial works. It also shows that sundials are geared to the rotation of planet Earth wherever they are located on Earth. It completes what makes the sundial moves in relation to the sun. Once the concept on how a Equatorial sundial or disk dial works at the South or North pole works. The Equatorial sundial or disk sundial can then be used to draw the hour lines on a horizontal or vertical sundial. There is a complete connection between all concepts. Not just part of it. And it describes it for both hemispheres not just for the Northern hemisphere. Sundial are also located in the Southern hemisphere. It can also be used to show that sundial hours on the dial face runs clockwise in the Northern hemisphere and anticlockwise in the southern hemisphere. I remember reading somewhere that. The reason that clock hours run clockwise is because sundials in the Northern hemisphere had their hours running clockwise. Someone may like to comment as to if this is true. In a classroom a globe or beach ball can be used to show the above concepts. Then the students could then use a Equatorial or disk sundial to draw hour lines on their own sundial. Then go outside in the sun to test their sundial. But 1st make sure they have their hats on and suntan oil on to protect them from the sun. That is what they do in sunny Australia. Have fun, Roderick Wall.
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