Clocks have been tied with human civilisation since ancient times, but now their importance is only realised when you’re late for work. For millennia, humans have been measuring time in various ways which include tracking the movements of the sun with sundials, the use of water clocks, candle clocks, and hourglasses. Our modern-day system of using a base-60 time system, that is a 60-minute and 60-second increment clock, dates back to 2,000 B.C. and comes from ancient Sumeria.
The first mechanical chronographs were invented in Europe around the start of the 14th century and were the standard timekeeping device until the pendulum clock was invented in 1656. There were many components that came together over time to give us the modern-day timepieces of today. Those components and the cultures that helped develop them have a long history.
Sundials
The earliest sundials known from archaeological records are shadow clocks (1500 BC or BCE) used in ancient Egyptian and Babylonian astronomy.
The Romans adopted the Greek sundials, with the first record of a sundial in Rome being in 293 BC. Plautus, a playwright, complained in one of his plays about the day being ‘chopped into pieces’ by these sundials! In 10 BC, the ancient Romans built a very large sundial called the Solarium Augusti. It is an obelisk, a very tall stone pillar that has a big base and gets thinner towards the top.
Candle Clocks were another ancient timekeeping device that was widely used around the world from China to England and Mesopotamia. Time sticks were developed in places like India and Tibet and the hourglass (which was widely used throughout Europe) came into being a little later.
The Chinese were able to develop a mercury version of a timekeeping device around the 10th century with the direct ancestors of mechanical clocks appearing in 11th century Iran.
Mechanical clocks
The first actual mechanical clocks appeared in 14th century Europe. These early mechanical clocks employed a mechanism called the verge escapement mechanism with a foliot or balance wheel for accurate timekeeping. The first examples were truly huge devices and relied on the use of heavy-weights to drive the clock’s hands. They were often built in tall towers and were able to keep relatively good time for long periods.
Some can still be found today with some examples in England and France dating to the 14th century. Many would prove to be exquisite works of art like the Prague Astronomical Clock.
Mechanical clocks would quickly prove their worth as being very reliable (for the time) and were the de facto timepiece until the development of the actual pendulum clock in the late 17th century by Christiaan Huygens. Galileo would show a little earlier, in 1581, that pendulums could be used to help keep clocks accurate so long as the pendulum was swinging.
The invention of the balanced spring and additions to clock balance wheels in the mid-17th century greatly improved timekeeping devices accuracy. Despite these advancements, pendulum clocks remained one of the most accurate clock designs well into the 20th century.
Quartz oscillators and atomic clocks
This was until the development of quartz oscillators and atomic clocks in the post-war years. In quartz clocks, an electronic oscillator which is regulated by a quartz crystal, is used.
Quartz is basically one of the most common minerals on earth. All quartz watches, including digital watches, keep time in the same way. They don’t have the same ticking mechanism as a quartz watch with a dial and hands, but they do keep time using the crystal.
How do quartz clocks actually work? Each quartz clock or watch contains a small piece of quartz, usually shaped like a musician’s tuning fork. The battery inside a quartz clock or watch sends electricity to the quartz crystal via an electronic circuit, causing the fork’s prongs to vibrate 32,768 times per second.
The circuit measures the number of vibrations, and generates one electronic pulse per every 32,768 vibrationsor, one per second. These pulses power the gear wheels forward, in turn moving the clock’s second hand (and minute and hour hands) clockwise around the clock face. Quartz clocks are both accurate and durable.
Digital watches
The mechanism of digital watches only has a few differences. As with analog, every second, the typical quartz clock’s electronics counts out 32,768 vibrations of the quartz crystal and then sends a 1-second pulse of electricity to the counter.
However, another alternative for keeping time on a digital clock is to use AC power with a constant 60-hertz oscillation. This regular oscillation can be exploited in the same way as the quartz crystal plane vibrates to provide the quartz clock an extremely accurate timekeeping system.
So, which watches are more accurate; analog, or digital ones? Well, taking a mechanical analog watch and a quartz digital watch and comparing their accuracy is the only way to do so. Because quartz technology is the most exact movement, the digital result is likely to be more accurate in this case.
Dinara Hettiarachchi
Grade 9
Ananda College,
Colombo 10