Clocks have an interesting past. Ancient Egyptians and Mesopotamians invented the very first time measuring device – the sundial. The first sundials were obelisks (3500 BC) and shadow clocks (1500 BC). Egyptian and Babylonian astronomers manufactured these devices. Using the shadow of the sun, they determined the times of the day. Astronomers divided each day into twelve parts, the hours. It is possible humans made primitive sundials, using wooden sticks even before but there is no archaeological evidence of this.
Sundials – the first timekeeping devices
The ancient Greeks adopted the designs from Egypt and Mesopotamia and applied new principles. Herodotus, the Greek historian, writes that the sundials were adapted from Babylonia by Anaximander of Miletus around 560 BC. Since the Greeks had far-reaching geometric insights and had studied the movement of the sun carefully, they were able to build a universal sundial that could be used anywhere on Earth.
The Romans in turn took over the Greek sundials. Not every Roman was happy with that, Plautus complained that his days were chopped to pieces by the sundials. Vitruvius described in his book De Architectura (ca.25 BC) all hitherto known types of sundials. In 10 BC, the Romans built a very large sundial, the Solarium Augusti – a classic solar marker with an obelisk.
More about time: What is time?
Water clocks
Another timekeeping tool, probably also invented in ancient Egypt or Mesopotamia, was the water clock. The advantage of this clock was that people could use it at night and on cloudy days. The height of the water level changed due to the supply and discharge of water in a reservoir. The passage of time was deduced from this. The Chinese had also invented a water clock, which consisted of water in adhering bowls spinning a wheel.
Islamic timekeeping devices
Islamic scholars took over the sundials during the Middle Ages and elaborated on insights from ancient times. Roman and older sundials did not have constant hours due to the changes of the season. In the summer, the hours lasted longer, as the sun spent more time in the sky. The principle of setting a standard for all hours was Ibn al-Shatir’s idea in 1371. He discovered that a vertical column placed parallel to the Earth’s axis produces shadows with equal hours for each day of the year. Western European clock builders adopted this improvement from the Arab world around 1445.
Mechanical clocks
In the Middle Ages, the hourglass was also invented, a device that could accurately measure a short period of time. Especially on ships, many hourglasses were used, because an accurate time measurement was crucial for navigation at sea. At the end of the Middle Ages, mechanical clocks made their appearance, replacing all previous timekeeping devices for good. The oldest timepiece was built in England in 1386. It now hangs in the Salisbury Cathedral. With the help of gears and weights, a clock indicates the passage of time.
Digital timekeeping
Over time, mechanical clocks replaced most other forms of timekeeping. Whole craft guilds of clock-makers arose. The mechanics became more and more refined, which made it possible to make watches quickly. The modern competitors of the mechanical timepiece are the digital clocks that run on electricity.