Before clocks were invented, time was kept using different instruments to observe the sun passing through the meridian at noon (the meridian is an imaginary line running from the North to the South Pole). The earliest instruments used for timekeeping that we know of are sundials and water clocks.
Sundials– (3500BC) A sundial is able to tell what time of day it is depending on the position of the sun. Ancient Egypt was the era which held the oldest known sundial. Sundials have their origin in shadow clocks, which were the first devices used for measuring the parts of a day. Shadow clocks divided daytime into 12 equal parts and these parts were divided into even smaller parts. This shows that Egyptians must have understood the concept of division. They also must have understood that the earth was spinning or the stars were moving, at a constant speed, and that that is the key to telling when time is passing. Although shadow clocks were perfectly accurate during the day, they relied on the movement of the sun and therefore when the sun went down or it wasn’t a very sunny day, they became useless. Due to this, the Egyptians developed different timekeeping instruments, including water clocks, and a system for tracking star movements.
Water Clocks- (1092) One kind of water clock was a small bowl with holes in the bottom of it, which was floated on water and filled up at a constant rate. The markings that were made on the side of the bowl indicated how much time had gone by, as the surface of the water reached them. Water clocks were commonly used in Ancient Greece.
Candle Clocks- (1400BC, introduced in medieval Europe in 885) again, this uses equally spaced markings, that when burned, indicate the passage of periods of time. This solved the problem of when there was no sun present in the sky, as candle clocks did not require the use of the sun. Which meant these were used mainly on cloudy days or at nighttime. Clock candles were used in Japan in the early 10th century. You Jiangu’s device consisted of six 12 inch long candles all of the same thickness and were divided into 12 sections (one inch thick). Each candle burned away completely in four hours, making each marking 20 minutes. Again, this shows the mathematical concept of division being used.
Wristwatches- From the early stages wrist watches were mostly only worn by women, while men used pocket-watches up until the early 20th century. Wristwatches were worn initially by military men around the end of the 19th century, when it was crucial that the men synchronised their watches in order to time manoeuvres during war without potentially revealing the plan to the enemy through any signalling actions were discovered. Pocket watches were seen as impractical and not secure enough, therefore they strapped them to their wrists in the heat of war.
There is a lot of debate of whether children in schools need to be taught how to read an analog clock, or whether they can rely on using digital time. According to Jennie Ito, who is a child development expert, “analog clocks help children understand the passage of time because they have hands that are consistently moving”, whereas a digital clock only shows numbers changing as time goes by. Analog clocks also represents time in multiples of five, again, creating links between mathematical concepts is really important here. I feel that without using analog clock in classrooms and revealing these links between maths topics, children will not have as broad a knowledge of mathematics. Telling the time on an analog clock is essential for wider society and I believe that without having that skill, children would be at a disadvantage. By giving children a history of time keeping, it will allow them to have a better understanding of the concept of time and why we need to keep track of it.
