How to make a standard watch

How to make the standard table is as follows:

Guibiao is an ancient astronomical instrument, which can be used to measure the shadow of the sun and determine the time and season. The following is a simple tutorial on making a standard watch to help you understand how to make a simple standard watch.

Materials:

A thin rod or pencil with a length of 20cm, a piece of paper or plastic board with a length of 10cm× 10cm, glue or double-sided tape, scissors, ruler or protractor, sunglasses or sun visor (to protect eyes).

Steps:

Prepare a thin stick Choose a 20 cm long thin stick or pencil and fix one end on a paper or plastic board. If there is no thin rod, you can use a pencil instead. Make a shadow mark on the other end of the paper or plastic board, and cut out a small shadow mark with scissors. This mark should be able to slide along the thin rod.

To make a scale, use a ruler or protractor to draw a scale line on paper or plastic board, one scale per centimeter. This scale line can help you measure the shadow of the sun. Add timestamps Write timestamps on paper or plastic board, such as 12, 3, 6 and 9 points. These marks can help you determine the approximate time according to the position of the sun.

Use a watch. On a sunny day, put your watch on the flat ground outside. Wear sunglasses or a sun hat to protect your eyes. Observe the shadow of the sun on the watch. As time goes on, the shadow will move gradually, and you can mark the position of the shadow movement on the standard table. Every hour, slide the shadow mark to the corresponding scale and record the time.

If more accurate time measurement is needed, calibration method can be used. For example, at a known time (for example, 12 noon), move the standard shadow mark to the corresponding scale. Then observe the shadow length at other time points, and draw a fitting curve according to these data to get a calibration curve. Compare this calibration curve with the actual time to obtain more accurate time measurement.

Maintenance and storage: after use, clean the watch and store it. If you don't use the watch for a long time, you can put it in a dry place and cover it with a protective cover. The above is a simple tutorial for making standard watches. You can learn more about astronomy and time by making standard watches and observing the shadow of the sun.