THE HISTORY OF TIMEKEEPING DEVICES

“Film a car speeding down a road. Speed up the image infinitely and the car disappears. So what proof do we have of its existence? Time is the only true unit of measure. It gives proof to the existence of matter. Without time, we don’t exist.” - Lucy (2014 Movie)

We measure time because time is a currency.

In his book ‘Future Shock’, Alvin Toffler explains that if the last 50,000 years of man’s existence were divided into lifetimes of approximately 62 years each, our species would’ve lived 800 such lifetimes. Of the 800 lifetimes that mankind has been in existence, only during the last four lifetimes has it been possible to measure time with any precision.

Our timekeeping devices have gone from being based on shadows cast by the sun, to the raw nature of gravity that causes sand to drain in an hourglass, to mechanical devices such as the pendulum, to the piezoelectric nature of quartz crystals and eventually all the way down to the electromagnetic waves radiated from little atoms of an element called cesium. As we look at the development of timekeeping devices across history, it becomes apparent that crafting timekeeping devices were not an easy feat. Each required a substantial understanding of physics, a very high level of precision and extremely skilled craftsmanship to be able to function as intended.

Timekeeping Device: Shadow Clocks

Examples: Obelisks, Sundials, Vertical Gnomans.

Timeline: 3500 BCE - 1400 AD

Working Principle: You can measure time based on a repeated process given that it is consistent enough - As the sun passes through the sky, the shadow of the tall object moves across the ground in a repeated fashion, on a daily basis.

Understanding required to craft: Precise knowledge of Latitude and Longitude.

Time division: Divided the day into 14 parts. 10 daytime hours, 4 twilight hours.

Value Added: Shadow clocks allowed ancient civilizations to structure the day into measurable units. This changed the way people lived.

Accuracy: The way the sun moves across the sky changes with the season, thus the length of an hour changed from season to season. Later iterations pointed the shadow clocks toward the nearest pole to solve this problem.

Limitations: Could not be used on cloudy days or at night. Timekeeping Device: Water Clocks

Examples: Clepsydra cited from Ancient Egypt, China and India.

Timeline: 1600 BCE

Working Principle: You can measure time based on a repeated process given that it is consistent enough - The increase in the volume of water within a vessel can be used to measure time if the water adding the volume to it does so in a consistent fashion.

Understanding required to craft: Basic understanding of viscosity.

Time division: Sexigesimal

Value Added: This was the first timekeeping device that didn’t rely on celestial cues for time telling.

Accuracy: Since a change in temperature affects a change in viscosity of a liquid, consistent timekeeping would also be significantly affected.

Limitations: Could only measure hours. Also, water freezes at 0 degrees celsius. It was later replaced with mercury which freezes at -38 degrees celsius. Timekeeping Device: Candle Clocks

Examples: Candle clocks in Chinese poems by You Jiangu, Candle clock system of King Alfred the Great of the 9th Century.

Timeline: 600 BCE

Working Principle: You can measure time based on a repeated process given that it is consistent enough - If it is assumed that a candle melts at a consistent pace, its stages of melting could be used to measure time.

Understanding required to craft: Understanding of wax as a material

Time division: A candle that is 12 inches tall and made of 72 pennyweights of wax takes about 4 hours to burn, thus every inch would represent 20 mins and 6 candles measured 24 hours.

Value Added: Allowed for timekeeping at night or on cloudy days.

Accuracy: Since a change in temperature affects a change in viscosity of a liquid, consistent timekeeping would also be significantly affected.

Limitations: This method required high maintenance and was uncyclic.

Timekeeping Device: Hourglass

Examples: Tower Clocks of Venice and Prague

Timeline: 800 AD

Working Principle: The time taken for the outflow of sand from an aperture was used to calculate time.

Understanding required to craft: The flow of sand through an hourglass is entirely different from the flow of liquid. In the case of a liquid.

Time division: Varied as per the kind of hourglass

Value Added: Ocean travel was required an accurate timekeeping to aid navigation - Time established longitude. The hourglass was ideal for this because the bobbing waves didn’t affect its accuracy the way it would for a pendulum clock. Famous Portuguese explorer Ferdinand Magellan had 18 hourglasses on his ship

Accuracy: Accurate within +/- 10 %.

Limitations: The device needed a user’s complete attention to be able to tell time beyond the length of the hourglass’s complete drainage from it’s aperture - Time was read upon the hourglass being drained of sand on one end. Since hourglasses did not have markings to easily read time, the duty of computing time rested on the hands of the user. Timekeeping Device: Mechanical Clocks

Examples: Tower Clocks of Venice and Prague

Timeline: 1100 AD

Working Principle: You can measure time based on a repeated process given that it is consistent enough - Most tower clocks used weights to keep the mechanism going, while the escapement (the part of the movement that counts the seconds) was a notched wheel whose movement was regulated by a back and forth movement. Accuracy varied greatly until a pendulum drive the escapement (1656 AD).

Understanding required to craft: Deep understanding of controlled mechanical energy conversions.

Time division: Sexigesimal

Value Added: Standardized what we meant by hour or minute.

Accuracy: With the exception of .Precision Pendulum Clock made by the harrison brothers, mechanical clocks only became as accurate as +/- 10 seconds a day.

Limitations: Required frequent maintenance and repair. Timekeeping Device: Pocket Watch

Examples: John Harrison’s H4, Patek Philippe 973J

Timeline: 1500 AD

Working Principle: You can measure time based on a repeated process given that it is consistent enough - Most pocket watches used a system of springs to keep the mechanism going. A mainspring stores mechanical energy, while a balance spring is used to count the seconds based on the moving parts

Understanding required to craft: Deep understanding of controlled mechanical energy conversions.

Time division: Sexigesimal

Value Added: This made timekeeping devices very portable and sowed the seeds to watches being associated as personal objects of value - to which one would attach notions of style and class.

Accuracy: Pocket clocks were largely inaccurate. It was with the invention of the H4, a pocket watch developed for the British Crown’s Longitude Challenge(1714), that we could calculate time with an accuracy of upto a second a day.

Limitations: Early pocket watches could only measure hours.

Timekeeping Device: Wrist Watch

Examples: Cartier Tank, Santos.

Timeline: 1900 AD

Working Principle: Wristwatches went from being powered by by the same mechanical movements as pocket watches, to being powered by quartz, PCBs, and GPS.

Understanding required to craft: Apart from understaning the mechanism,w ristwatches made it necessary for manufacturers to adopt an understanding of wrist based accessories.

Time division: Sexigesimal

Value Added: Wristwatches made it easier to look at time. Thus they were useful for pilots who need their hands on the flight controls at all times, or military personal who could look at time while still holding their riffles up and without shifting their line of sight. At the core of the wristwatch proposition was the idea that you could now wear time instead of carrying it. We’ll talk more about this at length.

Accuracy: This depended entirely on what movement was used.

Limitations: Early wrist watches were very prone to damage via shock or water. Timekeeping Device: Laptops, Cellphones, Practically any gadget.

Examples: Macbook, iphone, kindle..

Timeline: 2000 AD

Working Principle: Every gadget works differently

Understanding required to craft: Every gadget would require a different understanding to craft

Time division: Sexigesimal

Value Added: A lack of accuracy would affect stocks and shares, hence this is extremely accurate and in-sync globally. Watches no longer have a monopoly of time. Time can be read out of any device and this has changed how valuable the public perceives watches to be.

Accuracy: Atomic time is very accurate, it loses a second ever 15 billion years.

Limitations: Reading time from gadgets makes us prone to distraction. A lot of people take out their phone to check time and get carried away by the other notifications.