Posted: Jun 27 2014
As Spring moves into Summer, the days become longer and the Sun is out more - yay!!. A pleasant activity to do on a warm sunny day is helping your children to create their very own sundial or shadow sticks. It’s the perfect excuse to get them outdoors, teach them some science and take part in a hands on educational activity.
You can give your children a small history lesson by explaining to them that sundials were our first “clocks” thousands of years ago. As the Earth rotates around the Sun, the position of the Sun tells us what time of the day it is, according to its shadow. Explain how the Sun rises in the East and then sets in the West, and yet it is the Earth that rotates. You can demonstrate this by using a torch and a ball, perhaps something the size of a football. Let your child hold the torch still, acting as the Sun, while you rotate the Earth (you can place a sticker on the ball to represent where you live).
There are a few ways to build a sundial, from the very simple and easy to the more complex method which will require a compass. This would be a great time to practice using a compass and to teach your child about compass points. The simplest sundial only uses a stick and some pebbles.
- If you have a piece of pavement nearby, grab some coloured chalk and something long and thin that will easily stand up on its own. At noon, place your stick on the pavement and using the coloured chalk draw a line down the faint shadow that the stick makes. Go back every hour and draw down the shadow line again. Note and discuss the changing lengths of the shadow with your child.
- You can find the East-West line by using a very simple method. Place a stick upright and secure it in the ground, bearing in mind that a taller stick will give more accurate results. Mark the edge of its shadow with a pebble. The shadow will move from East to West in a curved line, wait 15-30 minutes before marking the next shadow’s edge with a second pebble. Draw a line from the first shadow tip to the next; this is an approximation of the East-West line. To find North, stand with the first mark on your left (West) and to your right will be East. Now you are facing North.
- Take a look at your atlas and find the latitude of your area. Using your compass, find true North, and then using a protractor, angle a stick so it matches your latitude. Point the stick North and secure it in to the ground. This will align your sundial with the Earth’s axis and provide a little more accuracy. Mark the shadows with small rocks at each hour. It’s best to set up this shadow stick first thing in the morning.