Hi all, The following is what I think is the best way to describe how sundials work to kids or anyone.
1st start with the largest sundial in the world. Planet Earth the Master sundial clock. Stick a vertical stick into the ground at the South pole or North pole. And describe how the shadow shows the time throughout the day. Draw the 24 hour lines every 15 deg and that 15 deg x 24 hours = 360 deg one day. Then show how the Equatorial sundial relates to our stick sundial at the poles. Place it at the South or North pole. And show that the Equatorial sundial style edge is parallel with the stick and the axis of the Earth. And that the hour lines are the same every 15 deg. And that it will keep the same time. Then place the Equatorial sundial anywhere on earth. And show that the sundial is geared to Earth the largest sundial in the world (the Master sundial clock). Therefore it will keep the same time. Show how the sundial time markings relate to your local time. And that the style edge of the sundial must be parallel with the axis of the earth and parallel with the vertical stick at the poles. And that at night time the sundial is in the shadow of Earth. Then place a horizontal sundial at the same location. And describe that the style edge is also placed parallel with the stick and the axis of the Earth. And how the hour lines are projected every 15 deg from the horizontal sundial style. That is to place the style edge of the equatorial sundial onto the horizontal sundial style edge and use it to project the hour points onto the horizontal base of the horizontal sundial. Then draw the hour lines on the horizontal sundial. Then show the direction the horizontal sundial faces if in the Southern hemisphere or Northern hemisphere. To ensure that the Style edge is parallel with the axis of the Earth and stick. Then go through the same process as you did for the horizontal sundial but with a vertical sundial on a wall. And show that it must face North towards the sun if in the southern hemisphere and face South for the northern hemisphere. Yes I live in sunny Australia in the southern hemisphere. Then show how the angle of the style edge relates to the latitude of the location of the sundial. To make the style edge parallel with the stick and axis of the Earth. Depending on how far you want to go. Describe how a horizontal sundial that is not designed for the latitude of the location you are at. Can be corrected if a block is placed under the dial to make the style edge parallel with the axis of the Earth and the stick. Describe how longitude relates to your location. And that the longitude time zones are every 15 deg. 15 deg x 24 hours = 360 deg one day. One way to describe the above is to use a globe of the world or a large beach ball. With cardboard cutouts for sundials. And a lamp (sun) to make the shadows. Young kids and some adults learn better when learning in the sand pit (concrete learning) rather that just using symbolic words (symbolic learning). That is how I explain it. If anyone wants to publish the above. Please do and let them know where it came from. Have fun, Roderick Wall Sunny Australia.
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