This week, Roy had a very firm idea of just what he wanted to do. He wanted to visit a garden, but one which people may not have visited before. I suggested visiting the Orange Botanical Gardens, because I had visited before and thought they were very pretty, especially in Autumn! When we arrived though, Roy changed his mind about just what he wanted to show you. Orange Botanical Gardens have many sculptures, but there was one which particularly captured Roys attention - a sundial.
This was not just an ordinary sundial, but one where the person telling the time becomes part of the sundial! Most sundials have a sculpted pillar called a gnomen in the centre or at one end which is used to cast a shadow which tells the time. The shadow changes position depending on the time of day, allowing the shadow to give an indication of time. Modern sundials are often made of metal and stone, and are often quite small, like the one Roy is looking at in the photo below. The sundial which Roy was so taken with, was huge though, and it was the time teller who was the pillar casting the shadow.
Sundials are very clever. As the name suggests, they use the sun to indicate what the time is. Each day the sun seems to move across the sky as the earth rotates, rising in the east, moving west across the sky and eventually setting in the west. As the sun 'moves', so do the shadows which it creates and by learning where the shadows fall at specific times of the day and marking them we can use the shadows to tell the time. The difficult part is that, because there are different daylight hours at different times of the year and the earth moves very slightly each day, changing the angle which the sun hits the sundial at very slightly, a simple sundial is not very regular. The sundial at Orange is quite reliable though as tells the person where to stand at specific times of the year which means that it compensates for this movement.
Sundials are really very interesting, not just because of the way they work, but because of their history. They are the oldest recorded instrument for telling the time, and also the oldest known scientific instrument in the world. They were even used for navigation, but that's another story! The first sundials were probably just sticks or stone pillars set into the ground which cast shadows and may have developed up to 7000 years ago! Later, in about 2500BC the Babylonians and Egyptians began to build obelisks, which are tall, tapering, narrow monuments. They cast moving shadows which formed a basic type of sundial and later on, marks around their bases began to indicate the time more fully. Egypt remained a leader in sundial technology and by 800BC they were building more precise sundials. One of these sundials, from about 800BC, is still around today! The sundial continued to develop and was used for centuries, even after the mechanical clock was invented in about 1300AD. In fact, in the 1700's, when watches replaced sundials, watches were unreliable and still actually relied on sundials to set the correct time!If you would like to learn more about the history of sundials, click here. You can also learn about how sundials work, see some very beautiful examples and even learn to make your own by visiting the World Liverpool Museum Website by clicking here.