Clocks and watches are everywhere in our society, but have you ever stopped to think about how they work? Human beings have been using some form of clock to measure time for thousands of years. The history of clocks has involved many different types of materials, ranging from the sun's light to quartz crystals and even atoms. Since each of these types of clocks had a human inventor, clock and watch history also involves some colorful characters! Here is an overview of how timekeeping evolved from ancient practices into the methods we use today.
One ancient method of keeping time was the sundial. This device shows the time of day by casting a shadow onto a round stone according to the position of the sun. Other timekeeping instruments have used materials that move at a predictable speed. For example, an hourglass uses finely ground sand pouring through a small hole, while an incense clock is based on the predicted time it takes for a stick of incense to burn.
A clepsydra, or water clock, was one of the first sophisticated instruments for measuring time. It was used thousands of years ago in Egypt, China, Greece, and other geographic regions. In these societies, a clock was typically used for astrology. By the 1200s in Europe, a new form of mechanical clock appeared that used weights rather than the flowing of water. These new clocks used a concept called escapement, in which power was released in slow, regular bursts.
Tower clocks, used to announce the time in a public way, often indicated the time only by bells. Most of these tower clocks were installed in church cathedrals as a way to designate intervals between prayers. Historians believe that the oldest working mechanical clock is at Salisbury Cathedral, where it was built in the 14th century. By the 15th century, some clockmakers were using a mechanism that was spring-driven. A clock given in 1430 to the Duke of Burgundy, known as Peter the Good, was the first one of this type. German inventor Peter Henlein created the first portable timekeeping device in 1504, which was also spring-driven. Jost Burgi developed the minute hand in 1577.
One major motivation for advancing the design of clocks was the need for precise timing in navigating ships. A pendulum clock would not be useful at sea, where the rocking motion of the ship would interfere with the pendulum's swing. John Harrison was the first to solve this problem with the invention of a pendulum-free marine clock. An innovation during the 17th century was Galileo's design for a type of pendulum clock. The first pendulum-based clock was manufactured during this time by Christiaan Huygens based on a mathematical formula. The innovation of pendulum clocks eventually led to the invention of longcase clocks, known today as grandfather clocks.
In the 16th century, wealthy European men wore portable timepieces in the form of engraved brass cylinders, which featured only an hour hand. These devices were not particularly accurate in keeping time. They were valued mostly as jewelry and featured ornate designs and shapes. Portable timepieces were initially bulky and heavy, but over time they became small and light enough to tuck into a pocket. Flat pocket watches became fashionable among men of high society by the 17th century. Pocket watches remained in common use until World War I, when soldiers were given "trench watches" to wear on their wrist for easier access to timekeeping. Wristwatches became the new fashion, with the majority of men using them instead of pocket watches by 1930.
Developments in the clock industry began speeding up in the 1800s, during the heyday of pocket watches. In 1840, Alexander Bain invented the electric clock, which was wound using a motor. In the late 1800s, Eli Terry patented a type of new clock that could be produced in large numbers. With the introduction of mass production in the 19th century, clocks were one of the first consumer items to be created on a production line. Clocks, which had once been owned only by the wealthiest families, were now available to the general public. Soon, technological advances changed the way clocks were made. Henry Warren began producing battery-operated clocks after 1912; meanwhile, engineer Warren Marrison built the original quartz clock in 1927 at Bell Laboratories.
The way we use these words today, a clock is any instrument that we use for displaying and measuring time. The word watch generally means a timekeeping device that you can wear. Modern clocks use an oscillator that moves back and forth at a predictable rate. Clocks in common use have an oscillator either in the form of a pendulum or a quartz crystal. Atomic clocks, which we rely on for the most accurate time measurements, use the vibration of electrons as an oscillator.
A clock's indicator is the way that it shows the current time. Originally, clocks used bells or chimes to indicate the time. In modern times, clocks and watches can have an indicator that is either analog, with moving hands to show the hours and minutes, or digital, with numbers shown on an electronic display. There are also talking clocks that indicate the time with spoken words and tactile clocks with displays that can be felt with the hands. Clocks have been built into computers, cellular phones, and other multipurpose devices since electronics were first introduced into mainstream society.
Clocks and watches are vital to us in today's world, where everything from employment to public transportation is built on a specific time schedule. We may take clocks for granted because we see them almost everywhere, but few of us could explain the inner workings of an analog wall clock or a digital wristwatch! From quartz crystals to atomic clocks, the modern design of timekeeping devices is an intricate and fascinating journey to explore. Use these links as a starting point for more information on clock and watch history, the inner workings of specific types of clocks, and fun ways to learning about telling time.
How Does It Work? (National Watch and Clock Museum)
The Galileo Project: Pendulum Clock
A History of the Evolution of Electric Clocks
Monticello Design and Décor: The Great Clock
Willard House and Clock Museum Virtual Tour
Tower Clocks Gallery: "Faces to the World"
The Long Case Clock: Engineering Behind a Grandfather Clock
Leonard Cutler: Commercial Cesium Clock
World's Oldest Mechanical Clock
Benjamin Banneker: Invented America's First Clock
Warren Marrison Developed the First Quartz Clock
John Harrison and the Longitude Problem
Why Is Clock Time So Important?
The Challenge: Build Accurate Clocks