Sundial a way to tell the time

Press, 24 December 1985, Page 10

Sundial a way to tell the time

Sun time — the way a sundial tells you the time — is the oldest way of timetelling there is. Sun time is the time birds, animals, and plants follow. A sundial tells you the time by the sun. The shadow of a pointer marks the hours and the shadow moves as the sun travels across the sky. The sun is in the south

half of the sky for people living in the northern hemisphere and for people living' in the southern hemisphere it is in the north half of the sky. You could make a simple sundial that will tell you sun time. It could not be exactly correct because you would need hundreds of lines and numbers to make up for changes in the time of the year.

Take a piece of wood about 25cm square with waterproof paint — or have

someone do that for you.

Use a compass to draw the largest circle you can on your piece of wood, leaving room around the outer edge of the circle for your numbers. Trace this half-circle to use as a guide to marking off the hours. Find the centre of your sundial, circle and place the centre of your -traced circle over the top. Because we live in the southern hemisphere you will need to use the bottom half of the sundial. Make small pricks, using a needle or pin for each section through to the bottom half of the sundial.

Lift the tracing paper and join each pin-prick to the centre of your circle and out to its edge with a ruler. This give spaces for 12 hours of daylight. Mark off the hours of the day around your half-circle. Start at six o’clock in the

left-hand side and end with six o’clock at night on the right-hand side. Noon, or midday, is in the middle. Next, colour in your numbers.

The next thing you need to complete your sundial before you put it in the garden is something . to make the shadow. A knitting needle, or skewer, or kebab stick, would do. A hole must be made in the centre of the sundial for this pointer. You might need some help with this because the hole needs to be made with a hammer and nail, or drill. Your {jointer — skewer or knitting needle — must fit snugly and stand straight up.

Next, go into your garden and choose a spot that will be in the sun all day (when the sun is shining). The midday mark must point south.