TIL dowsing is considered a pseudoscience. I was taught how to find gopher tunnels, water and electric lines as a child and found out when googling for ideal lengths for single L copper rods!

I'm having a serious WTF moment about this; it was taught to me that what you are measuring is the magnetism of the terrain, because disturbed earth IS something you can scientifically measure using, well, many instruments really. Seismometers can tell you if there's a trench if you go knocking on the ground for example, or there are actually instruments that use a type of sonar to detect caves.

The idea of dowsing as taught to me is simply, if something has either recently been disturbed OR if there is something conductive with flow within a few feet of the surface, the magnetic field will be disturbed and the rod, if held steady and balanced but loosely, will turn as it meets that disturbance. I can attest that both my father and I recently flagged (accurately) a yard and successfully located a breach in the water line using uncoated 20" coat hanger wires bent into an L. They aren't the best material but he was even able to demonstrate a depth checking method involving stomping on the ground. I wasn't able to replicate that though.

There's certainly a lot of stuff about it that is slightly sketch, but it checks out as far as finding water and electric lines for sure. And gopher tunnels. Not that that will do you much good.

/r/todayilearned Thread Link - en.wikipedia.org