Every day I sit at my desk, looking toward the green wall of Signal Hill on my left, and the South Atlantic Ocean to my right. To be tired of that view, one would be tired of living in Cape Town, to paraphrase the reputed saying of Dr. Samuel Johnson.
Directly in front of me, across the red-tiled roofs of an apartment complex, stands the clock tower of Reddam House (http://asb.reddamhouse.com/), a well-respected private school.
But despite the reputed quality of the school’s teaching, the accuracy of the school’s clock leaves a lot to be desired. During my almost five years of living here, the clock has rarely displayed the correct time. It has always been a few minutes slow and it has frequently stopped for days after a heavy rain storm or strong winds. Recently one of the segments of the clock face disappeared in a high wind, and for a time, there was only one hand on the side facing me. To compound the confusion, the four faces of the clock don’t all display the same time, on the occasions when the clock actually works!
I confess that I find it very frustrating to see a clock that is often only accurate twice a day. But here in Green Point, we have a reliable alternative: the Noon Gun. Every day, save Sunday and public holidays, it booms across the city, at precisely 12:00. And these days, the guns are fired by an electronic signal from the South African Astronomical Observatory.
,The Noon Guns – there are two of them, with one as a backup, stand above the city at the end of Signal Hill. This historic time signal has existed since 1806. Originally the guns were located in front of Cape Town Castle, but were relocated to their position on the hill in 1903, no doubt to the relief of the city residents and all pigeons.
The guns were cast in 1794 and were brought to Cape Town during the 1795 occupation. They are reputed to be the oldest guns in daily use in the world.
If you stand in the square by the Cape Town Stadium, at precisely noon, you can get a practical example of the difference between the speed of light and the speed of sound. You first see the puff of smoke from the cannon and what seems like at least a second later, you hear the boom, for light travels at about 300 million metres per second, almost a million times faster than sound, which trundles along at only 340 metres per second. The difference is even more apparent from further away at the promenade along the ocean.
It sometimes occurs to me that Reddam students have excellent local conditions to enable them to conduct experiments to measure the difference between the speed of sound and light.
But they can’t rely on the accuracy of their clock!