How did ancient people know that there were 365 days in a year? Who found it?
2. The idea of measuring the length of a year was put forward by Guo Shoujing in Yuan Dynasty. He built an observatory in Dengfeng, Henan. Using the length of its shadow to measure the estimated time, and later invented an auxiliary observation instrument, called "fine auxiliary". And the specific time of a year is calculated by Zu Chongzhi. The return year is 365.2425 days.
Extended data:
1. Punctuality method (punctuality method) comes from the need of arranging work and life. Timing methods include date planning and time planning. Date planning is to prepare a calendar to specify the date; Time planning is a descriptive method to define the time of day. The description method of defining time is the cornerstone of compiling calendar; At the same time, the way the calendar is compiled is also counterproductive to the time planning.
2. Historically, China's ancient timekeeping methods mainly included 16: 00, 10: 00, 100: 00, 12: 00 and the 60-point method introduced with Buddhism. The "hour" mentioned here refers to the time period.
(1) decimal system
Decimal system is a natural choice, so early calendars and times only used decimal system. The yin-yang and five-element calendars belong to the October solar calendar; Decimal system is the decimal division of time. In the early stage of ten o'clock use, several key natural phenomena, biological reflex and living habits are selected as time nodes to help people know the time. Later, it was gradually changed to numbers, or codes such as heavenly stems.
According to the annals, the five time nodes during the day are: tide, rain, middle, easy, and; The five time nodes at night are: A, B, C, D, E, which gradually turned into additional time service nodes during the night security patrol, which lasted until the late Qing Dynasty.
(2) Hundred Carvings
The centimeter system is a further division of the ten-hour system, that is, the ten-hour system is further divided into a balanced hundred-hour system. Engraving may have originated in the Shang Dynasty, and there are unearthed Han Dynasty sundials. The scale on the disc is 69 carvings that may be used for carving. On the other hand, people's demand for the accuracy of time measurement and the proposal of the hundred-engraving system promoted the appearance of copper pot dripping (after all, it was not difficult for the ancients to divide the circumference by one hundred two thousand years ago).
In the Han Dynasty, it was changed to 120, and in the Southern Dynasty, it was changed to 96, 108. After many twists and turns, it was not until the introduction of European astronomical knowledge in the late Ming Dynasty that the reform of 96 engraving books was put forward and made it a formal system in the early Qing Dynasty.
(3) Sixteen-hour working week
The 16-hour system is a by-product of calendar calculation. China's early calendar changed from a five-element calendar of Yin and Yang to a calendar of four seasons and eight festivals. When a year is divided into twelve months, there will be a score with 16 as the denominator. The ancients realized long ago that the length of a year is 365 and 1/4 days. If it is divided into 12 months, then each month is 30 and 7/ 16 days. Sixteen-hour system is a time division with calendar calculation.
Fifteen of the sixteen time nodes recorded in Huainanzi Astronomical Training are: dawn, dawn, dawn, flea (early) food, banquet (late) food, angle, center, small return, late time, big return, high return and low return.
(4) Twelve-hour working day
Since the Western Zhou Dynasty, China's calendar has gradually stabilized the concept of twelve months a year. Taking a day as a year, we also divide a day by twelve o'clock, and fix the date demarcation point (date change point) at midnight.
Twelve time nodes (starting points) at twelve o'clock are twelve o'clock. With the diversification of people's work and life, their words are gradually unsatisfactory, so they are represented by twelve earthly branches, including eleven o'clock in the evening, one o'clock in the morning, three o'clock in the morning, five o'clock in the morning, seven o'clock in the morning, nine o'clock in the morning, eleven o'clock in the afternoon, three o'clock in the afternoon, five o'clock in the evening, seven o'clock in the evening and nine o'clock in the evening.
Since the Song Dynasty, there has been a mechanical Chen Si in China, which drives the turntable through gears and brings little Woodenhead with time cards into view. When the time is between two hours, the time card that appears in the field of vision is inconsistent with the original expression. So the expression of time adopts two benchmarks: the first appearance of the time card, the correct position of the time card, the immediate start and the correct time.
(5) Time system and shift system.
The time system is used in conjunction with 12 and 100. The early expression was "time x moment", that is, "time x moment"; After the Song Dynasty, it was "X at the beginning, X at the right time", that is, "X at the beginning, X at the right time"
With the introduction of Buddhism, the Indian method of 60 minutes a day was introduced to China, which was used in conjunction with the 10-hour system to form the overtime system. Commonly used expressions are X-point, X-point and X-point. X raises Y point, reflecting that the ten-hour system is easier to calculate than the twelve-hour system in calendar calculation. When the bell and drum tower tell the time, there are usually more drums, and the clock is six o'clock.
References:
Baidu encyclopedia-ancient timing