Things You'll Need
Instructions
Hammer the nail into the center of the wooden block so that it stands vertically.
Place the wooden block in the center of a sheet of 11-by-17-inch paper in a spot that will stay sunny all day. If the location is breezy, weight the corners of the paper down with small rocks.
Trace around the block to mark its position. Use a compass to find which way is north, and draw an arrow pointing north on the sheet of paper in case its position gets changed accidentally.
Mark the position of the tip of the nail's shadow, and label the mark with the current time. At regular intervals, such as once per hour, check the sundial, mark the shadow's new position, and label it with the time of day.