How to Make a Sun Dial
Before clocks and watches were invented, there was the sundial. Sundials were created and placed in strategic areas where people can determine the time by the shadows the sun struck across it. Imagine a clock with no hands, instead a straight edge of a shadow pointing at what time it is. Recreate this ingenious invention with these steps.
Tools
Maps
Protractor
Drafting Compass
Felt-tip pens
Pens
Pencils
Common nails
Cardboard or wooden disks
Hammer
Procedure
Use a perfectly round disk made from heavy cardboard or light wood as your sundial’s base. Locate and mark the center of the disk using a pen.
The gnomon, or the hand of the sundial, is the object that provides the shadow that in turns provides the time. The item can be a pen, pencil or nail.
Find your location’s latitude. Remember, the sunlight falls differently in different locations! Determine your latitude using a map or by looking it up on the Internet.
Put the gnomon at the center of the disk. Measure the angle of the gnomon to the disk face, it should equal to your latitude angle.
You can manually calculate each hour interval by calculating the angle for each hour. Draw the lines from the base to the 12 noon line, going up. Use the tan D = (tan t)(sin Ø) formula, where t = time measured in degrees and arc. Ø is the latitude of your location and D = the angle you are calculating.
Alternatively, you can do it the easy way and go online to find a site that will let you input your latitude formation, calculate the angles, and give you a sundial face diagram that will give you the correct time. Print out the sundial face diagram, put it on the disk, and have the gnome line up with the radiating vertical line. Make sure that the center of the disk should be where the horizontal and vertical lines intersect.
Transfer the lines from the printed paper onto the disk. The lines should be coming from the center going outwards. After completing the lines, indicate the hours that each line represent.
Finally, take the sundial out in a spot where it is exposed to the sun at all hours of the day. Point the gnomon due north. The shadow should fall along the correct or appropriate time line.