When I was in high school, we had a new principal. One of the first things he did in office was to get the school a Quadro machine, to help identify and diminish our school’s drug problem (we weren’t aware there was a drug problem). At any rate, the thing looked something like a Star Trek phaser with a car antenna out the top. You’d hold the box-part in your hand, and the antenna would extend in front of you. When you plugged the appropriate “chip” (one for alcohol, one for marijuana, one for cocaine, etc.) in the back and walked down the school hallway, the antenna could somehow detect the chemical in the offending student locker, and when you triangulated the location by walking the hallway from the opposite direction, you could claim reasonable suspicion, which is enough to search a locker without student permission.
When the school body (not to mention the staff) got wind of this and performed a collective eye-roll, the principal brought in Quadro company people to demonstrate the device in front of everyone. While no students worked the machine properly (although the company people could), the principal wasn’t deterred. A few nerds from the Physics Club (*ahem*) asked to examine the device. We asked if we could open it up and look at the circuitry, so the company people opened the hollow box for us. And it was hollow. No electrodes (what did the chips plug into?), no wiring… just air. When asked how the machine worked, we were told, “It works on the aura of the user!” Our principal was still undeterred with this news (“Isn’t that fascinating?!”), but the school got its money back a few months later when the FBI investigated the company for fraud.
What makes dowsing rods so compelling?
There’s a new article today about Egypt’s hepatitis-C dowsing rod, and links to the patent. There’s a bunch of these things out there (thanks, Wikipedia!), of similar car-antenna design, and mostly debunked. I understand the desire to have a quick and easy way to find horrible things like explosives and disease, but sensing the molecules in the air is pretty preposterous.
That being said, there is evidence that trained animals may be able to detect seizures, cancers, or even death. You’re better off getting a pet to detect molecules than a fancy, expensive dowsing rod.