Deepening Understanding YR5 Non-Fiction Text the History of Time-Keeping by Laura Curtis

Deepening Understanding YR5 Non-fiction Text The History of Time-Keeping by Laura Curtis

For thousands of years, human beings have marked the passing of time, whether it be a day, a month or the passing of year through observing the seasons or the hours of daylight and darkness. Over this time, people began to use their ingenuity to create actual devices to measure and keep track of time. Time as we know it today can be measured down the nearest millisecond. Yet how did our current methods of recording time come into existence? Let us now explore this remarkable concept.

Ancient Time-Keeping Thousands of years ago the Ancient Egyptians lived. Their way of life was so sophisticated - much of the knowledge they held is now sadly lost to us - that they created one of the first ways of recording time. They divided the day into two 12-hour periods, and used large obelisks (a tall, tapering stone pillar) to track the movement of the sun. Sundials were also one of the earliest ways of tracking time. However, sundials would, of course, only function when there was sunlight so to compensate for these shortcomings, the water clock was invented, examples of which date back to the Babylon (a key kingdom in ancient Mesopotamia from the 18th to 6th centuries BC, today’s eastern Mediterranean including Iraq and Iran). Although no one is certain when or where the first water clock was made, the oldest known

Photocopiable for educational purposes only example is dated to 1500 BC and is from the tomb of the Egyptian pharaoh Amenhotep I.

In ancient times, there were two different types of water clocks: outflow and inflow. In an outflow water clock, the inside of a container was engraved with lines an equal distance apart and when water dripped inside (at a steady pace) people could tell the time by measuring the change in water level. An inflow water clock followed the same principle as an outflow one but water was dripped from one container into another.

Water clocks were used as an efficient time-keeping device for thousands of years; they were employed frequently by the Ancient Greeks, who called them clepsydrae (meaning ‘water thief’). Records indicate that water clocks were used in Athens for the timing of speeches in law courts and sources even show they were used during the speeches of various well-known Greeks, including Aristotle (c. 384 B.C. to 322 B.C.) who was an Ancient Greek philosopher and scientist.

Other ancient timekeeping devices include the candle clock, used in ancient China, ancient Japan, England and Mesopotamia; the timestick, widely used in India and Tibet, as well as some parts of Europe; and the hourglass, which functioned similarly to a water clock.

Time-Keeping in the Middle Ages During most of the Middle Ages (from roughly 500 to 1500 A.D.) technological advancement was at a virtual standstill in Europe. Sundial styles evolved and water clocks were still used but they didn't move far from ancient Egyptian principles. Eventually, around the start of the 14th century, human beings decided to create an even more efficient method of tracking time and the first mechanical clocks were invented in Europe; these became the standard timekeeping device for the next few hundred years.

Large mechanical clocks first began to appear in the towers of several Italian cities in the early 1300s and worked by using a ‘verge-and- foliot escapement’ or mechanism. The ‘verge’ (or crown wheel) drives the ‘foliot’, a primitive type of balance wheel, causing it to oscillate back and forth; it controls its rate by allowing the gear train to advance at regular intervals or 'ticks'.

Photocopiable for educational purposes only The Astronomical Clock at Hampton Court Palace is one of the most brilliant clocks ever to be invented. It was designed by the Bavarian Nicholas Cratzer but the actual construction was by the French clockmaker Nicholas Oursian, probably a French clockmaker and his assistants. As well as telling the hour, the day and There are three concentric copper dials, which all rotate at different speeds using a gearing system which shows the month, the phases of the moon, the signs of the zodiac, the movement of the sun and most usefully for the members of Henry VIII’s court, who travelled by barge along the River Thames, the time of the high tide at London Bridge.

Another advancement in design - sometime between 1500 and 1510 - was an invention by Peter Henlein, a German locksmith from Nuremberg who created spring-powered clocks. Popular among wealthy individuals due to their smaller size, they were the first portable timepieces and were precursors to truly accurate timekeeping. Mechanical clocks were used until the invention of the pendulum clock in 1656 by Christian Huygens which were regulated by a mechanism with a "natural" period of oscillation. Huygens' pendulum clock had an error of less than one minute a day, the first time such accuracy had been achieved, whilst refinements reduced his clock's errors to less than 10 seconds a day. Around 1675, Huygens developed the balance wheel and spring assembly and it is still found in some of today's wristwatches.

Modern Day Time-keeping The pendulum clock remained the most accurate timekeeper until the 1930s and 1940s, when quartz oscillators were invented. Quartz clocks work by using quartz crystals. When an electric field is applied to the crystal, it causes the crystal to vibrate and generate a constant frequency electric signal that can be used to operate an electronic clock display. In the 1960s, microelectronics meant that quartz clocks could be both compact and cheap to manufacture and by the 1980s they were the world's dominant timekeeping technology in both clocks and wristwatches. Atomic clocks are now far more accurate than any previous timekeeping device, and are used to calibrate other clocks and to calculate the International Atomic Time.

One thing is for certain: time waits for no-one. All we can do, each and every day, is make the most of the time that we have.

Photocopiable for educational purposes only