Keeping Track of Time
image by benkersey/sxc.hu
Long before clocks were invented, man kept track of time by the position of the sun and moon in the sky. According to Merchants Passage, the use of sundials to calculate time by the angle of the shadow cast from the sun goes back thousands of years. Although many sundials are elaborately decorated stone, you can make a simple wooden sundial from scraps that will work just as well as commercial sundials without the expense of purchasing one.
Cut a 12-inch diameter circle from a piece of 3/4-inch plywood. Sand the edges with medium-grade sandpaper. Paint the wood if you prefer.
Cut a 6-by-6 inch square from ¼-inch plywood. Trace a line from corner to corner and cut to form two triangles. Discard one triangle.
Place the triangle so that its point lies at the center of the circle and the 90-degree angle rests on the perimeter. This is the gnomon of the sundial. The shadow cast by the sun against the gnomon provides the basis for marking time. Glue the triangle in place with wood glue.
Place the sundial in an area that receives full sun. Observe the position of the shadow cast by the gnomon and mark the position to indicate hours around the perimeter of the sundial. You may wish to use decorative paints, decals, press-on numbers or simple markings to indicate the hours.