What is Automatic watch?

Automatic watches are made up of about 130 or more parts that work together to tell time. Automatic movements mark the passage of time by a series of gear mechanisms, and are wound by the movement of your wrist as you wear it. The gear train then transmits the power to the escapement, which distributes the impulses, turning the balance wheel. The balance wheel is the time regulating organ of a mechanical watch, which vibrates on a spiral hairspring. Lengthening or shortening the balance spring makes the balance wheel go faster or slower to advance or retard the watch. The travel of the balance wheel from one extreme to the other and back again is called oscillation. Lastly, automatic movements come in different types, including movements that are Swiss-made, Japanese-made, and more.
Also referred to as self-winding, watches with automatic movements utilize kinetic energy, the swinging of your arm, to provide energy to an oscillating rotor to keep the watch ticking. They're considered more satisfying to watch collectors (horologists) because of the engineering artistry that goes into the hundreds of parts that make up the movement. If you do not wear an automatic watch consistently (for about 8 to 12 hours a day), you can keep the watch powered with a watch winder (a great gift for collectors). You should refer to your owner's manual for recommended service intervals.

Automatic Watch Maintenance
Although automatic (also called "mechanical") watches do not have batteries, some easy-to-follow maintenance is necessary for continued and long-lasting good use.
Self-winding automatic watches depend on the movement of the arm to operate and do require some winding, even if you wear your watch on a daily basis.
If you wear your automatic watch every day, it is best to wind it once every two weeks to keep the wheels in motion and oil fluid. Simply wind the crown (the same knob used to adjust the time and date) until you meet slight resistance If you do not wear your automatic watch every day, you should try to wind it at least twice a week to ensure continuous operation, as well as keeping the inside mechanism in complete running order.
If you have a mechanical watch, it is best to wind it at the same time every day. This is extremely beneficial for the mechanism. You may want to make it a routine, winding it every morning when you wake up. If your watch has a day/date function, avoid setting the day and/or date at night. The day-date mechanism is activated during the nighttime hours and could be disrupted if set at this time.
What is the difference between a Mechanical Movement and an Automatic movement?
A mechanical movement is a movement based on a mainspring which when wound slowly unwinds the spring in an even motion to provide accurate timekeeping. As opposed to a manual mechanical watch which needs to be wound on a consistent basis, an automatic mechanical requires no winding because of the rotor, which winds the mainspring every time you move your wrist (see our section on automatic watch maintenance for more details).