Where did hours and clocks come from?

For most of human history, there have been only three divisions, namely day, month and year. By nearly 4000 BC, the ancient Egyptians who had entered the stage of civilization felt that the existing real-time methods were too inaccurate because they always did something besides food and clothing.

Ancient Egyptian scientists invented the hour. They divided a day into 24 hours, and this division is still used today. They divided the 24 hours equally into 12 hours of day and 12 hours of night.

Why does the decimal system appear? Could it have been invented by a strange man with six fingers on both hands?

This is because there are two periods in the early morning and evening that are not day and night. The ancient Egyptians also divided the day into ten parts based on the number of fingers, each part was two hours long, and then gave one part in the early morning and one part in the evening. This became a nondescript 24-hour system.

There is a problem with the hour bisection method. As the seasons change, the length of day and night will also change. The ancient Egyptians’ solution was to make the hours flexible. In summer, the hours of day are longer than the hours of night. Hours are long, and when winter comes, their respective 12 hours will remain unchanged. Because the ancient Egyptians insisted on equal distribution, the new basic unit of time, the hour, was very inconvenient to use. People had to invent another thing: a timer.

This is sundial, which is the Chinese sundial. It took nearly three thousand years for a real sundial to take shape. The early sundial was a very simple tool to determine time based on the shadow of the sun. It was basically a stick inserted in the ground to see the length of the shadow.

After a long blur of years, in the sixth century BC, a decent sundial appeared. It is said that it was invented by the Greek Anaximenes of Miletus. But at this time, other regions such as Egypt and China also had similar timekeeping tools. During the Zhou Dynasty, the earliest time-keeping instrument appeared in China, the Gui watch. It was divided into two parts. The watch that stood on the ground to measure the shadow of the sun was called a watch, which is the origin of the Huabiao. The watch that was placed flat to measure the length of the shadow was called a Gui watch because of the time and the shadow of the sun. It is related that the name "time" came into being.

China has used the hundred-quarter timekeeping method since ancient times, dividing day and night into one hundred quarters. By the time of the Han Dynasty, day and night were divided into twelve hours, which was based on the introduced ancient Egyptian timekeeping method. Sundials like discs had previously replaced standard watches and became the main timekeeping tool, and they were also imported. Later, Western learning spread to the east, and the 24-hour system was introduced to China. In order to correspond, the original hour was called hour or big hour, and the new hour was called hour. Also for the sake of correspondence, one hundred quarters was reduced by four quarters to become ninety-six quarters, with eight quarters per hour and four quarters per hour, giving rise to the term "one quarter".

Sundials are not easy to read, nor are they easy to make. They have to be adjusted according to the latitude where they are located, and they have to be adjusted with the changes of the seasons. One of the main reasons sundials are inaccurate is that the hours themselves are not a fixed concept, but become longer or shorter with the seasons. Around 127 BC, Hippachos of Nicaea in Alexandria proposed fixing the 24 hours. Later, Claudius Ptolemy of Alexandria further divided the hour into 60 minutes, with the day starting at noon and ending at noon. In 1925, it was changed to start at midnight.

However, as a matter of convention, people everywhere are still accustomed to using the old flexible hour system. The two timing methods have been used for thousands of years. It was not until the emergence of mechanical clocks that the fixed hour system replaced the flexible hour system. In China, time was not fixed until the introduction of Western mechanical clocks.

Another problem with sundials is that they cannot keep time at night or on cloudy and rainy days. To solve this problem, the clepsydra (water clock) appeared, which is called a clepsydra in China.

Water clocks first appeared in ancient Egypt and Babylonia. The earliest existing physical evidence is around 1400 BC, while the written evidence can be pushed back thousands of years. The Chinese engraved inscriptions appeared much later. It is also an imported product.

The water clock uses the principle of water balance and dripping, and is not restricted by climate, daylight and seasons. It is a big step forward than the sundial. By 800 AD, there was a water clock that could tell time by dropping a metal ball into a bowl.

Water clocks also have many problems. Water drops penetrate stone, and if the water clock is used for a long time, the outlet will slowly widen, and time will become faster and faster. Water is also affected by climate. If the weather is too hot, the water will evaporate and time will disappear. If the weather is too cold, the water will freeze and the water clock will stop working at all.

Zhang Heng’s armillary sphere in the Eastern Han Dynasty was a power system based on the water clock. Several similar things appeared in later generations, reaching their peak with Su Song in the Song Dynasty, when the puppet time telling function appeared, but these The stuff is basically used in astronomy.

Churches in the West are all in the market. There are many churches among the chickens and dogs. The worship time is fixed. You can’t knock first and then knock intermittently to let God hear it. What does it look like? A certain monk invented the first mechanical clock in 1275. This mechanical clock was driven by a weight that slowly slid down. It was reset after a few hours. It was much more accurate than a water clock, and it also told time. Function, telling the monks that it is time to ring the bell.

In 1300 AD, the balance wheel appeared, and the minute hand also appeared, telling time more accurately.

More than 100 years later, coil springs began to be used in door locks and pistols. The watch industry introduced this technology and created a spring-driven clock in 1430. The weight and size of the clock were greatly reduced, allowing people to carry it, and the development of clocks began. Popularization process.

The spring-driven clock also has a big problem. It runs fast at first, and then gets slower and slower because of energy consumption. To solve this problem, clockwork was developed that could be re-wound to provide energy and is still used today.

One day, there was an earthquake in Pisa, an Italian city on the Mediterranean coast. The most famous building in Pisa is the Leaning Tower of Pisa. There was a man on the tower who watched with interest the chandelier swaying during the earthquake, and even took his own pulse. , calculate the time it takes for the chandelier to swing once. This person was Galileo. He discovered that no matter how far the chandelier swings, the time it takes to swing from one end to the other is the same. In 1656, Dutch scientist Christian Huygens designed a pendulum clock that used a pendulum to replace the gravity gear. In 1675, William Clermont invented the anchor escapement.

But this thing didn’t work at sea, because wind and waves were like a pendulum clock. Huygens solved this problem. In 1674, he invented the stabilizing hairspring, which immediately caused a revolution in the watch industry. . The stability of Huygens' hairspring was uncertain. In 1761, the British inventor John Harrison connected the main spring and hairspring to create a watch that was both accurate and easy to carry. It could not only be used on ships, but also be used by other people. Wear it on your wrist. This design is the basis of today’s mechanical watches.

Clocks keep running 24 hours a day and are accurate. They are the most accurate among machines. By around 1950, quartz watches appeared and were more accurate than human-made machines. Then there are atomic clocks, which are accurate to less than one second slower every thousand years, so no one can stick to the day when the clock is inaccurate.