The motive force of modern clocks is mechanical force and electric power. A mechanical clock is a timer that uses the energy released by a heavy hammer or spring as the power to drive a series of gears, adjusts the speed of the gear train with the escapement governor, and indicates the time and measures the time with the pointer. Electronic clock is a modern emergence of electric power, liquid crystal display digital and quartz pointer type timer.
Clock glass is also called clock mirror, it is not only convenient for the wearer to read the time at any time, but also to protect the dial and hands. There are many kinds of clock glass materials, respectively sapphire glass, tempered glass, plexiglass three categories
Sapphire glass: The physical and chemical properties of this mirror are very stable, and the hardness is very high. Second only to diamond, it can easily cope with scratching, wear and erosion. But hesitation hardness is too high, toughness is not good, very afraid of falling. But many high-end watches will use this watch mirror!
Plexiglass also has a name called "acrylic glass". The hardness of the mirror of this material is not very good, and it is easier to scratch. But its willfulness is very good, not easy to break. The cost of plexiglass is very low, and many low-end watches generally choose this kind of mirror.
How to identify the material of the watch glass:
First of all, you can tap the mirror to judge the material of the mirror from the sound. Acrylic mirror will make a sound like plastic, judging from the Angle of weight, acrylic mirror is the lightest, sapphire mirror is the heaviest. In addition, the thermal conductivity of sapphire is very good. Therefore, when you touch it with your hand, it will have a cold feeling. Finally, the sapphire mirror is far smoother than the mirror of the other two materials, so if you drop a drop of water on the sapphire mirror, the water drop is not easy to spread on the top, and other materials will scatter into a piece.
