What is the difference between quartz and automatic movements in watches?

Automatic watches are self-winding ie. they need no battery and are wound by the slightest movement of the owner's wrist. Rolex invented the modern automatic back in the 1930s.

A quartz watch is powered by a battery - it keeps time by pulsing electrical current through the tiny quartz crystal, which oscillates at a predictable rate and hence keeps very accurate time. Quartz watches can have either an analog dial with the traditional hands or have a digital display - or both.