As a civilization, we’ve always been preoccupied with time. Our clocks regulate our lives, telling us when to eat and sleep, when to go to work and come home, and more.
Today, smartphones and other forms of digital display measure time. For centuries, though, certain civilizations relied on natural elements—sun, water, and earth (sand)—to guide their daily activities.
Read on to learn more about the interesting elements in time keeping!
The first timekeeper is arguably the sundial, which was also known as a shadow clock. It measures the time of day by the position of an object exposed to the sun. As the hours passes and the sun crosses the sky, the shadow of the object moves accordingly across a specially designed surface.
The earliest sundials appeared around 3500 BC. An Egyptian mainstay for centuries, they primarily consisted of a straight base with six time divisions inscribed on its surface and an elevated cross-piece at one end. The base was positioned with the cross-piece at the east end during the morning hours and the west end in the afternoon. The shadow cast by this object would indicate the time.
In 280 BC the Greek astronomer Aristarchus of Samos invented the hemispherical sundial. It was a hemisphere-shaped bowl that used a strategically positioned pointer to cast shadows. This sundial was especially popular in Muslim countries, where it was used to indicate prayer times; it remained in use until well into the 10th century.
Sundial use migrated to Europe in the 14th century and remained steady, even after mechanical clocks were introduced. These shadow clocks were more sophisticated than the early ones, having a face with equal hours laid out. There are reports of them being used to reset mechanical clocks until the late 19th century.
Water clocks first appeared in Egypt around 1600 BC, using a technology and design borrowed from the Babylonians. These devices released a quantity of water from one vessel into another, taking a specific amount of time to do so.
In Greece, a water clock known as a klepsydra was installed in the Athenian law courts to regulate how long a speech could last. The Greek and Roman armies also used them for timing shift-work.
More sophisticated clocks began appearing around 280 BC in Greece. When water entered these devices, a floating drum rose, turning a cog whose movements were regulated and measured. In the 4th century BC, the agora of Athens contained a clock that held 1000 liters of water, enabling it to measure an entire day.
Although the sand clock, which is also known as the hourglass, is a basic timekeeping device, there is no evidence of it being commonly used before the early 14th century. Strangely, it came into vogue around the same time that the first mechanical clocks appeared.
Design-wise, sand clocks consisted of two connected glass bulbs, positioned vertically so that material could trickle from the top to the bottom. When the top bulb was empty, a certain amount of time was deemed to have passed. Sand was the most common material used, although powdered marble and eggshell were installed in some devices.
Different clock sizes were invented to measure specific amounts of time: bigger ones could cover up to three hours, while Christopher Columbus used a half-hour sand clock to keep track of the seven canonical hours. One design had four separate glasses, each one measuring the four quarters of the hour.
In England, sand clocks were often inserted in coffins, symbolizing that the deceased person’s time on earth had run out. A popular hymn went, “The sands of time are sinking, the dawn of heaven breaks.”
The Atomic Age
Today we use atomic clocks for accurate time measurement. But seeing how far the science of timekeeping has progressed since the sundial made its first appearance, it will be interesting to see what the future brings.
It’s Your Turn!
Tell us what you think the future will bring in terms of timekeeping? What do you hope to see?