Method for manufacturing standard watches

The production method of standard watches is as follows:

You can use materials such as scale, cardboard and double-sided tape to make standard watches. Fold the card paper to make a watch, and then put the watch upright. Fold another piece of cardboard, draw a scale with a scale, make it into a GUI, and tile it. Standard watches are connected with double-sided tape. A standard watch is ready! It is not only convenient to obtain materials, but also simple to make.

The height of the sun changes in different seasons, and the length of the shadow at noon changes in different seasons. Standard watches are designed and manufactured by using this principle. The main function of a standard watch is to determine the position of the winter solstice, and then determine the length of the tropical year. In addition, we can also determine the direction and solar terms by observing the changes of surface shadows.

Expand:

The main function of a standard watch is to determine the position of the winter solstice, and then determine the length of the tropical year. In addition, we can also determine the direction and solar terms by observing the changes of surface shadows.

For a long historical period, the accuracy of the tropical year determined by China ranks first in the world. Through further research and calculation, ancient Han scholars also mastered the length of the sun shadow in the standard table of 24 solar terms. In this way, the standard table can not only be used to formulate festivals, but also be used to discharge the dates of the future solar calendar year and the twenty-four solar terms in the almanac, as an important basis for guiding the agricultural activities of the working people of the Han nationality.

As early as the 20th century BC, during the period of Taosi ruins, the standard table drawing method was used in the Central Plains of China. In the Han Dynasty, scholars also used the length of the sun shadow in the standard table to determine the "twenty-four solar terms".

Using the standard chart drawing method, the shortest day in the Yellow River basin is determined as the winter solstice, and the winter solstice is the starting point of the "twenty-four solar terms". The period from winter solstice to the next winter solstice is divided into 24 segments (each segment is 15 days), and the number of days between every two solar terms is average. The ancients called this method "calming qi method" (also called "average time method").

The high watch made by Guo Shoujing in Yuan Dynasty was designed to increase the growth of standard watches. In the past, there were several difficulties in using standard watches. First of all, the shadow edge is not clear. The closer the shadow is to the edge, the lighter the color is, and it is difficult to determine where the shadow ends. If the boundary of the shadow is not clear, the length of the shadow cannot be measured accurately.

Secondly, the technique of measuring the shadow length is not accurate. In ancient times, the length of a ruler was generally only energy to minutes, which could be estimated to centimeters, that is, one tenth. According to the traditional method, the shadow length of winter solstice is measured. If there is a little error in the measurement, the calculated winter solstice time will have an error of one and a half hours.

Faced with these difficulties, Guo Shoujing designed an altimeter and created an auxiliary instrument called "Jingfu" to improve the measurement effect.