Create a simple sundial by using a box approximately 25 cm high. Set it up on a flat surface in a sunny location outside so that one corner always points North.

Attach a large piece of paper to the North corner of the box and position it East - West. The size of the paper should be twice the height of the box. Mark the points where the North and South corner sit on the paper.

Each day mark the shadow of the tip of the North corner at the following times: 8 a.m., 12 Noon, and 4 p.m. Record the time of the observation beside the marked shadow. At the end of the day, draw a smooth, curved line through the three points.

Are the shadow marks always the same? If not, how do the shadow marks differ from day to day?