The wearer's arm actions cause a weight behind the movement to rotate, winding the mainspring. They can also be wound manually. The batteries send electronic impulses through a small bar of synthetic quartz crystal which vibrates more than 32,000 times per second. Those vibrations are channeled through a series of gears that result in one impulse per second. Quartz analogs are watches in which the hands are moved by the electronic impulses passing from the battery through the quartz crystal to a step motor which moves the hands.
Quartz watches are generally more accurate than mechanical watches, for two reasons.
One, mechanical watches have many moving parts. That means more friction and less accuracy as the parts interact. Digitals have no moving parts. Two, the quartz crystal's constant and amazingly frequent vibrations per second enable watches to measure the second with unprecedented accuracy. Besides telling the hours, minutes and seconds, many watches reveal the month, day and year.