Everyday Things: Time at the bar

We all use them, but where did they originate? The word ‘clock’ comes from the French word “cloche” meaning bell, but long before clocks were on the scene, we used nature to tell the time. The first humans used the position of the sun to estimate the time of day. Obviously there were problems during heavy cloud or at night of course! The Egyptians, in about 3500BC constructed huge obelisks to use as sundials; these cast shadows on the ground, which changed position throughout the day. By 1500BC, smaller sundials appeared, although they all had the same limitations at night or on very cloudy days.

The first hourglasses were built in about 1340BC, and consisted of a bowl with a hole in the bottom. Water dripped slowly through the hole as the day wore on, and a scale cut into the side of the bowl measured the time. They worked on cloudy days and at night - better than sundials - but they needed careful calibration to be accurate. The Greeks built the first alarm clock in 250BC. It was a water clock where the rising water kept time and eventually hit a mechanical bird that triggered a whistle!

It was the Greeks too, who first divided the year into twelve parts called months and each month into thirty days. Originally, the Egyptians and Babylonians decided to divide the time from sunrise to sunset into twelve ‘hours’, then divided the night from sunset to sunrise in the same way. However, this system was not very accurate because of the varying day and night length throughout the year. So finally, the day was divided into 24 hours of equal length and time could be measured far more accurately. The idea of dividing hours and minutes into 60 parts came from the Babylonians some 4000 years ago - they used base 60 to do their astronomical calculations.

It was not until about 700AD that hourglasses containing sand were used. They were restricted to mainly small amounts of time, because heavy sand got stuck in the centre if they were too big.

The first leap forward in time technology happened in the 1300s when mechanical clocks, using weights or springs, appeared. The earliest clocks had no faces or hands, and just struck a bell on the hour. In the 1400s, the coiled spring was used for the first time; these enabled clocks to have moveable hands, as well as the weights or springs of the larger timepieces. This discovery also made it possible to make smaller clocks, and later, watches.

Peter Henlein invented the first portable timepiece in Germany in 1504. The first person to reportedly wear a watch on their wrist was the French mathematician and philosopher, Blaise Pascal; he attached his pocket watch to his wrist with a piece of string. In 1577, Jost Burgi invented the minute hand as part of a clock made for the astronomer Tycho Brahe, who needed an accurate clock for his stargazing.

In 1656, Christiaan Huygens invented the pendulum clock. This used weights and a swinging pendulum and was far more accurate than any previous clock; typically out by less than a minute a day, compared to 15 minutes a day in earlier clocks. The bizarre cuckoo clock was first made in c.1730, and the style is specific to the Black Forest.

After years of trying, in 1761, John Harrison finally made a clock that would keep accurate time at sea, as at the time, many sailors died because they lost position on the ocean, and pendulum clocks didn’t work at sea as the ships rolling offset their swinging motion. His tiny pocket watch lost only five seconds in 6½ weeks.

An American, Levi Hutchins, invented the first mechanical alarm clock in 1787. However, it would only ring at 4 am! Almost 100 years later, in 1876, Seth E. Thomas patented a mechanical wind-up version that could be set for any time. Eli Terry developed machines and techniques in the 1800s that manufactured clock parts exactly alike, enabling them to be mass-produced and swapped between one clock and another. Clocks were suddenly affordable to anyone.

It was about this time that many countries realised the need to create standard time zones so everyone could agree on the time, and countries could work together more efficiently. In 1852, the telegraph network in the UK started transmitting “Greenwich Mean Time”, and in 1884, members of 25 countries met to organise the world time zones.

Quartz crystal clocks were invented in 1920; when electricity and pressure are applied to quartz, the crystals vibrate at a very constant rate. These vibrations move the clock hands very accurately. A Swiss man, John Harwood, invented the self-winding watch in 1923. It was, perhaps surprisingly, only women who wore wristwatches at the start of the 20th century, but during WW1, many soldiers wore them, as it was easier than taking out a pocket watch during battle! After the war had ended wristwatches became popular everywhere. First, analogue watches, then digital ones in the 1970s and ‘80s became popular, as they still are today.

The next great innovation in timekeeping came in 1967, with the atomic clock. This used oscillations of caesium-133 atoms to tell the time. Currently, the NIST-F1 caesium fountain atomic clock, is the most accurate clock in the world - and is off by only one second every 20 million years. No excuses to ever be late again!