The first sundial appeared in ancient Rome. But they were not very accurate, like the hourglass, fiery and candlelight. To this period can be attributed the invention of more accurate water hours. The real revolution was the emergence of mechanical models in the 13th century.
History of mechanical watches
Mechanical devices were very heavy and bulky. They required constant monitoring. The watch is constantly being improved. They began to install on city towers. Some models of ancient watchmakers are real works of art. They indicated not only time, but also the movement of the sun, moon and planets. The movement with a dial and a clockwise hand was developed only in the 16th century.
Wrist Watch
The first watches were invented at the beginning of the 19th century. But they are not widespread. At the beginning of the last century, pocket watches were more popular. During the First World War, the military began to use watches. In the 30s, watches are still a luxury item. Only after the 70s did they become an everyday item. After all, cheap quartz movements were developed at this time.
In the 21st century, smart watches with many features were invented. Such models can even replace phones. Currently, mechanical watches are used as jewelry and an indicator of social status. Modern wristwatches are a useful device with many additional options. Manufacturers equip their watch models with tachometers, thermometers, voltmeters and other functions. They help owners in a variety of everyday activities. Watches with a tachometer and voltmeter are especially popular among motorists.
Tachymeter
One of the most popular features is the tachometer on the watch. It is used by motorists, travelers and athletes. Chronometers are usually equipped with this option. This is a very accurate watch, certified in Switzerland. They cost much more than conventional models. They should not be confused with chronographs. This is the name of the watch with a stopwatch. In such models, the watch mechanism and stopwatch work independently of each other. Modern chronographs allow you to measure the time of two simultaneous processes. They are used in their work by the military and doctors.
Every student knows that thanks to formulas that are related to time and distance, you can calculate the speed of an object. If you track the time on the chronometer, knowing which path the studied object has traveled during this time interval, then dividing the distance by time, you can get its speed. Modern models can do without additional calculations and quickly give the desired result. An additional scale is applied to them. Fixed tachymetric marking is located on the rim of the watch. First you need to start the tachometer on the watch or start the measurement when the second hand is at the initial mark. After overcoming the base segment, the tachometer is stopped (the position of the arrow is fixed). The arrow will indicate the speed in the base segments per hour. The usual tachometer on the watch allows you to measure speed up to 60 km / h.
Some manufacturers apply more complex scales to their models. Now, driving kilometer posts along the road, you can use the tachometer on the clock. By clicking the button on the first and finishing measurements on the second column, you can estimate how much time is required for the road.
How to use a tachometer on a watch
The principle of operation of the tachometer is very simple. Speed is the distance divided by time. The scale calculates the function 3600 / time in seconds. Using a tachometer, labor productivity can be measured. To do this, determine the manufacturing time of a unit of production. The arrow on the instrument will indicate the number of parts produced per hour. Other devices also work on this principle. The telemetric scale is designed to determine the distance to the object using sound. To do this, measure the time between a flash of light and sound (lightning and thunder). If you have difficulty with the calculations, refer to the manufacturer's instructions.
Other options
Modern watch models are equipped with not only an indicator of the current time, alarm clock and calendar. Repeater - the battle mechanism in wrist models, informing the owner what time it is. The most expensive models are equipped with a minute repeater.
Flyback is a chronograph function that allows you to start and stop the stopwatch, and reset the time with one button. In conventional models, two buttons are used that are located opposite each other. A countdown counter is used in yacht chronographs.
World time indicator - an additional rotary dial on a watch. It was invented in the 30s of the last century. Typically, these models are equipped with an additional dial to determine the time in another time zone.
Standby indicator - a device that indicates the remaining time of the mechanical watch models. Dynamometer - an indicator of accuracy of hours. Shows the length of time when you can trust the device.