Just about everyone who follows mainstream news knows about the fake bomb detectors.
So there's not much more I can cover, but heres a quick over view what it is and what dowsing is.
Dowsing is the ubiquitous method of finding water under ground. You simply find a long Y shaped stick, hold it under some pressure and let the ideomotor effect take over. Dowsing rods come in all kinds of configurations. The now famous