How do e-cigarettes work?

Though first created in China in 2003, e-cigarettes that produce a vapor alternative to regular nicotine cigarettes are just now finding major popularity in the U.S. But how exactly, do they work?

"TechKnow" breaks it down:

Watch "TechKnow," Sunday 7:30ET/4:30PT, to see Crystal Dilworth explore e-cigarette culture and examine the health implications of smoking alternatives.