What does a sundial mean?

The original meaning of a sundial refers to the shadow of the sun. Modern "sundial" refers to a kind of timing instrument used by ancient humans to measure time, also known as "sundial". Its principle is to use the projection direction of the sun to measure and divide the time, which usually consists of a pointer (watch) and a surface (scale watch seat). The sundial timing method is a great invention in the field of astronomical timing, which has been used by human beings for thousands of years.

There are scales on both sides of the coffin. Molecules, Ugliness, Yin, Mao, Chen, Si, Wu, Wei, Shen, You, Xu and Hai have twelve hours, and each hour is divided into "the beginning of the time" and "the right time", and a day is exactly 24 hours. ? [3] Most sundials show apparent solar time, and some of them have been changed in design to show standard time or daylight saving time. The sundial can display not only the time of day, but also the solar terms and months. Of course, its shortcomings are also obvious. It is huge and cannot be used when there is no sunshine, such as cloudy days and cloudy nights.