What is an automatic watch?

Automatics are fully mechanical, self-winding wristwatches.  The first automatics were invented in 1777 by Swiss timekeepers.  They are usually wound by the user before wearing it out, and they continue to wind up during the day from the motion of the arms.  They use a mainspring to keep the watch running, and a rotor weight helps the watch stay wound during the day.  The spring has enough tension to work through a full day.  People take pride in owning automatic watches, winding them and displaying their open skeleton mechanism.  One note is you have to be careful to not over wind the watch manually by turning the crown too far. Once you feel that the spring has reached its limit and does not want to turn further, don't push it anymore forward. Instead, let the self winding mechanism wind the watch for you during the day.  If you plan on using it the next day, its a good idea to give it a few turns of the crown to wind it up.  This will keep it running through the night.