Instead of telling time based on where the Sun is, they used water flow to divide out each hour. Greek water clocksįrom 400 BC, Ancient water clocks were a little more complicated than sundials. That is because there are not always 24 hours in a day, which means that an hour’s length would vary depending on where you are located relative to your time zone. However, this method was not very accurate because there are variations in how long it takes for the Sun to reach its highest point depending on where you are located on Earth (due to things like latitude and weather).įor a sundial from ancient Greece or an Egyptian obelisk from 3000 BC to approximate what we use today as Greenwich Mean Time, they would have to be calibrated differently for different locations. A sundial works in a fairly simple way: it uses the position of the Sun to calculate what time it would be if it were noon all across the world at once and tells you that time every hour on the hour. The earliest instance of dividing the day into hours is generally considered when people began using sundials. It enabled more precise timekeeping and helped usher in the Scientific Revolution and other advancements that would follow and change the world forever!Ī Timeline of the Earliest Types of Clocks Sundials and obelisks from Ancient Egypt The invention of the mechanical clock was a big step forward for society, as it improved on the previously used sundials and water clocks. The invention of the clock was so important because up until then, people relied on crude measuring instruments such as sundials and water clocks, which needed occasional correction and had very inaccurate timekeeping. Other claims say it was Christian inventors who lived at around the same time as Al-Jazari. It is unclear who invented this technology first some claim that it was Al-Jazari, a Muslim scholar living in 12th century Persia. These clocks were installed in towers and were later adapted to be portable. Sundials and obelisks from Ancient Egyptīuilt in 13th-century Europe, the first mechanical clocks were striking clocks used to warn the public of an imminent hour.A Timeline of the Earliest Types of Clocks.The first pendulum clock created by Salomon Coster of the Hague, and dated 1657, is preserved in the Museum Boerhaave, Leiden, The Netherlands. The increased accuracy resulting from these developments caused the minute hand, previously rare, to be added to clock faces beginning around 1690" (Wikipedia article on Pendulum clock, accessed 12-25-2011). The long narrow clocks built around these pendulums, first made by William Clement around 1680, became known as grandfather clocks. The seconds pendulum (also called the Royal pendulum) in which each swing takes one second, which is about one metre (39.37 in) long, became widely used. In addition to increased accuracy, the anchor's narrow pendulum swing allowed the clock's case to accommodate longer, slower pendulums, which needed less power and caused less wear on the movement. The anchor became the standard escapement used in pendulum clocks. Clockmakers' realization that only pendulums with small swings of a few degrees are isochronous motivated the invention of the anchor escapement around 1670, which reduced the pendulum's swing to 4°-6°. In his 1673 analysis of pendulums, Horologium Oscillatorium, Huygens showed that wide swings made the pendulum inaccurate, causing its period, and thus the rate of the clock, to vary with unavoidable variations in the driving force provided by the movement. "These early clocks, due to their verge escapements, had wide pendulum swings of up to 100°. The introduction of the pendulum, the first harmonic oscillator used in timekeeping, increased the accuracy of clocks enormously, from about 15 minutes per day to 15 seconds per day leading to their rapid spread as existing 'verge and foliot' clocks were retrofitted with pendulums. Galileo had the idea for a pendulum clock in 1637, which was partly constructed by his son in 1649, but neither lived to finish it. Galileo discovered the key property that makes pendulums useful timekeepers: isochronism, which means that the period of swing of a pendulum is approximately the same for different sized swings. Huygens was inspired by investigations of pendulums by Galileo Galilei beginning around 1602. "Huygens contracted the construction of his clock designs to clockmaker Salomon Coster , who actually built the clock. This technology reduced the loss of time by clocks from about 15 minutes to about 15 seconds per day. In 1656 Dutch mathematician, astronomer, physicist and horologist Christiaan Huygens invented the pendulum clock in 1656 and patented it in 1657.
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