Our daily lives revolve around time and to know the current time we rely on clocks. For thousands of years telling time has been a very important part of life for many reasons. We often take these time-telling devices for granted, never stopping to consider how they function or their vital assistance in prevention of losing our jobs or missing class; also clocks enable us to attend set appointments, meetings or events.
Sundials
First documented in Egyptian and Babylonian history, the earliest sundial was a tower-like structure called an Obelisk, which would cast a shadow when the sun was shining, defining the time of day. Later a sundial in a circular shape with a large protruding beam called a gnomon was crafted. As Earth orbited the sun, the shadow cast by the gnomon would meet with marked “hour” spots on the face of the dial. Obtaining the correct time on a sundial was an exact science; the sundial had to be positioned in alignment with True North. The face of the device usually indicated hours between 8 a.m and 8 p.m. Because the rotation of the Earth is consistent, this method of telling time was actually more accurate than even the earliest mechanical clocks to be invented thousands of years later. However, there was one major downfall to sundials: on an overcast day the people were simply out of luck! In addition to this, telling time at night was not a possibility; this is where the water clock gained importance.
Water Clocks
The oldest tangible time-telling piece in existence today is a water clock dating back to about 1400 BC. Water clocks were one of the first time-telling devices known to man along with the sundial. The earliest record of this type of clock was recorded around the same time as the first sundial, described in Hieroglyphics on Amenemhet’s tomb in Egypt. That inscription implies him as the creator of the water clock. Early water clocks consisted of a large steep-sided basin with a small hole, allowing water to drip into another basin below. As water dripped at a consistent rate through the hole, it would fill slowly to marked “hour” lines in the bottom basin. Later water clocks had a mechanism much like a water mill wheel into which water dripped; as the compartments on the wheel filled, it would turn and cause an attached bell to ring or object to move as a signal of time lapsing. Water clocks were invented because priests needed to perform strict rituals at night at a specific time, and of course the sundial could not be consulted during these hours.
Pendulum Clocks
Surely, everyone's familiar with pendulum clocks?
Around 1200 AD was the turning point for clocks, as a large faceless clock was invented. This device had heavy weights attached by a chain, which had to be hand-wound. As the chain unwound by means of the weights pulling on it, hours were signaled by the sound of a bell. Spring-powered clocks did not emerge until the 1400s and clocks did not display minutes or seconds until nearly the 1500s. Galileo inspired the idea used in 1656 by craftsman Christiaan Huygens to use a pendulum. This type of clock was composed of a pulley cord power source which was sped up by a wheel. A mechanism called an escapement was attached to this by way of a coiled spring and functioned to keep the clock from unwinding irregularly. The motion of the wheel would cause a ticking, or back and forth movement which is how the pendulum swings at a consistent rate. Gear-controlled clocks worked similarly, but instead of a pendulum, they simply displayed a clock face of minutes and later, seconds. Early clocks were notoriously inaccurate in the fact that several minutes or even an hour was lost each day.
Gear-Controlled Clocks
Today there are many types of clocks used. Most gear-controlled clocks are very similar to the pendulum clock in the respect of how their components work together. An escapement is perhaps the most important piece, keeping the clock ticking at a regulated pace. Some clocks are also powered by the aid of quartz. This hard mineral substance is beneficial to clocks because it has the capability to conduct a precise and consistent vibration frequency when in contact with an alternating current power source. Referred to as piezoelectricity, this process involves quartz being cut in an exact manner in which it will vibrate at about 32,768 hertz. As the vibrations occur time may be counted by either a digital display, as seen in digital clocks, or converted to a normal clock face. Of course to function, a quartz clock must be powered by a battery or electricity.
Atomic Clocks
All hail our friend, The Atom!
Perhaps one of the most intriguing modern clocks is the atomic clock. During their beginning years on the market in the 1950s, atomic clocks were very large and heavy. These devices function by way of atomic resonance. Contrary to popular belief these timepieces are not run on radioactive waves; they function by micro-waves and are powered by energy changes in atoms. Regulated by means of a satellite system in accordance with Greenwich Mean time, the atomic clock is the most accurate and precise timepiece in existence today. In recent years, these clocks have become a popular gift and desired item. Their cost is still significantly higher than a simple quartz clock but their accuracy is unrivaled, making them a must-have necessity for all scientists. Similar to the atomic clock is the radio-controlled clock. Radio clocks are regulated by a GPS system that sends signals to the clock; the central GPS system actually receives its time regulation from a real atomic clock. So in essence, radio-controlled clocks may be explained by being considered as “second-hand” atomic clocks. Radio-controlled clocks are often found on computers and radios, or in clock and watch form.
Atmos Clocks
Sometimes confused with the atomic clock is the Atmos brand clock. Atmos clocks are produced in Switzerland by Jaeger-LeCoultre. These clocks are unique in the fact that their power source is atmospheric elements. When the temperature changes just a fraction of a degree, power is created by reaction with gases and ethyl chloride in a compartment. The rising and compressing wind the mainspring and cause rotation. These clocks must be precisely designed for minimal friction and a pendulum which does not require a lot of power to work is used. Truly an energy efficient timepiece, the Atmos clock does not use any electric or battery power and is a the only self-winding mechanical clock. Considering the thousands of years in time-telling history, the past 300 years have been the most pivotal in perfecting accuracy and precision.
And Last But Not Least…
Finally, we also have the online alarm clock, which is the basis for the website which produced this blog.
Our online alarm clock runs using JavaScript, which is an object-oriented scripting language used for programming functionality on websites. Our alarm clock simply “reads” the current time from your computer’s own time settings. And here’s a tip: if you ever want to change the time zone displayed on OnlineClock.net, simply change the time settings for your computer!
We hope you’ve enjoyed this overview on different kinds of clocks and how they work.
We now wish you Happy Clocking!
Related Alarm Clock Blog Posts: