Ask an Amateur Scientist
: Dowsing

By Brian Thompson

I. The Setup

I don’t know when they came on or which channel showed them, but somehow as a kid I watched almost every Looney Tunes short in existence.  (I could say a similar phenomenon occurred between me and Saved by the Bell, but I’m pretty sure the fact that I’ve seen every episode of that show has something to do with its endless after school repeats on America’s “superstations” and my complete lack of friends.) And though I enjoyed watching Daffy Duck’s emotional breakdowns and Elmer Fudd’s frustrations as a closeted homosexual, there were a few things about those cartoons I just wasn’t old enough to understand.  Why did Bugs Bunny hate the Japanese so much?  And who the hell is Humphrey Bogart?  This second question was answered after I finally saw a revival of Casablanca with a girl who would have much rathered I took her to Scream II and told me as much by never answering my calls again.  And in regards to the first question, I finally realized that Bugs is just an unrepentant racist.

But there was one short that took a little longer to figure out.  In it, a man with a Y-shaped twig walks back and forth around an open field until the twig points downward.  And you could tell the twig pointed at the ground of its own accord, because the animators helpfully included little lightning bolt squiggles emanating from the tip.  He then tossed the twig aside and dug until water started gushing from the soil.  I don’t know what was supposed to be funny about this cartoon, though I’m pretty sure it had something to do with how nasty the Japanese are.  Or maybe something about how some Mexicans are lazy and others can run faster than the speed of sound.  Or about French people being rapists.  I don’t know, I got a lot of weird ideas from Looney Tunes, is what I’m saying.

It wasn’t until many years later when I read an article in USA Today (the newspaper for America’s illiterates) on the rising popularity of dowsing.  Dowsing, you see, is the act of looking for water, oil, old Coke bottles, or anything else using some kind of mystical tool—often a Y-shaped twig.  The dowser doesn’t consciously know where the things are that she’s looking for.  No, she relies on…well, something to move the stick or the coat hangers or the pendulum or whatever she’s holding in her hand to tell her she’s getting close.  The article went on to say that dowsing is an ancient practice that is used by thousands of people every year.  And then there was a pie chart or something.  This was USA Today, after all.

I don’t know what it was, but something made me suspicious about this whole dowsing thing.

Actually, I do know what it was.  Dowsing is completely absurd.

II. The Findings

There are basically two kinds of dowsers—map dowsers and field dowsers.  Map dowsers use a map to determine where something is buried or hidden.  Since most maps are too small to walk on while holding a Y-shaped twig (unless we’re talking about one of those comically large maps our TV networks used to show us how many states magically turned blue on election night), map dowsers most often use pendulums.  They hold some sort of weight by a small chain and move it over a map until the weight spins or rotates or swings side to side.  As with any kind of dowsing, map dowsing is fairly open to interpretation, so only the dowser can tell you what the particular movements of the pendulum are supposed to be.  And also like any other form of dowsing, the objects a map dowser can claim to find vary enormously.  So, if you’ve hired a map dowser to look at a map of the property you just bought in Massachusetts and tell you where the inbred mutant Kennedy fetuses are buried, he’ll pull out his pendulum (I like to think from a pocket in his cape) and waves it over your map until it jiggles a little.  Jackpot!

Field dowsers are the more common type, but the idea is basically the same.  Traditionally, they walk around outside with a Y-shaped twig held parallel to the ground.  When the twig points down, that’s where you dig.  Of course, twigs can always be substituted for a couple of coat hangers bent in an L-shape.  Some dowsers hold these wires loosely in their hands until they cross over one another, and others wait until the wires move apart.  You know, whatever.  You can even buy purpose-made dowsing rods—basically L-shaped metal sticks with handles for easy rotating—that serve the same function.  I received my own pair of dowsing rods as a birthday gift this year, and I can’t think of a better present except for anything else.

So what’s making these pendulums/sticks/wires/rods point/shake/swing/rotate?  Dowsers don’t really have a clue.  Go to any one of the depressingly many dowsing websites out there, and you’re likely to come across a different explanation.  Like almost every other pseudoscience, there’s a lot of talk about “energy”, though there’s almost no talk about what kind of energy they’re referring to or where it comes from.  Others believe that the dowsing device is just a mechanism for the dowser to demonstrate her innate, unconscious psychic powers.  In other words, the dowser knows where the stuff is, but she doesn’t know she knows.  Still others point to mystical “ley lines”  in the Earth, but there’s no evidence those exist either.  And that wouldn’t make any sense when it comes to map dowsing.  But, really, does any of this need to make sense?

USA Today was correct in saying dowsing is still surprisingly popular around the world, and it’s no wonder.  Some would point to the large number of financially successful dowsers as evidence that no matter how dowsing works, people wouldn’t pay to use dowsers if they didn’t produce results.  But the fact is that the vast majority of dowsers are employed to find water.  In California alone over the last couple of years, water has been fairly scarce, and many people are trying anything to ease the pain of drought.  But what dowsers and dowsing believers don’t seem to realize is that water can be found beneath the surface of almost every part of the Earth.  In fact, 98% of the Earth’s usable fresh water is ground water, and ground water is sixty times more plentiful than water from oceans or streams.  It’s a pretty fair bet that if water can exist underground somewhere, it does.  It’s just a matter of how much digging you want to do.

To really test the abilities of a dowser, you can’t go by their success in simply finding ground water.  In order to be useful, a dowser should be able to determine how deep the water is and how much is available.  In 1949, an experiment was set up to do just that twenty-seven dowsers in Maine were tasked with finding out where, how much, and how deep the ground water was in a given area.  Simultaneously, a trained geologist and an engineer were set on the same task.  All of the dowsers failed, while the people with real jobs used actual knowledge to accurately describe the ground water content in sixteen areas of the same field.

But what about dowsers who aren’t looking for water?  Well, there aren’t any hard numbers to tell whether any of them are very successful at finding anything.  But if you’re looking for an explanation as to why any stick or rod or pendulum would seem to move of its own accord, science has you covered.  The unconscious, barely perceptible movement of your hands is known as the ideomotor effect.  Hold anything out at a distance from your body, and it’s going to move.  You aren’t consciously moving it, but you don’t have control over these tiny spasms in your muscles.  If you’re holding a rod or twig or pendulum, those tiny movements can be translated into noticeably larger movements by the time they make it to the end of the object.  Hold up your iPod by the headphones, and you’ll notice that just a slight twitch of your fingers will make it swing.  Hold the end of a pencil between your fingers, and you’ll notice a similar effect.  Just because things look like they’re moving by themselves, it doesn’t mean they’re under any sort of mystical influence.

III. The Conclusion

But despite the fact that there’s no explanation for how it works and no evidence that it works at all, dowsing continues.  In fact, dowsers regularly apply to be tested by magician and debunker James Randi for his Million Dollar Challenge.  I’ve mentioned the challenge in this column before, but for those who don’t know, Randi’s foundation offers a million dollars to anyone who can demonstrate paranormal powers under controlled experimentation.  His dowsing tests have involved asking dowsers to find underground pipelines, and another experiment involves lining up a row of sealed cans full of either water or sand to determine if the dowsers can distinguish liquid from desert.  Over and over again, the dowsers have failed to do any better than one would expect from random chance.  And just like they have a million explanations for how dowsing works, they have another million for why it doesn’t seem to work when anyone’s paying careful attention.  It’s electromagnetic interference!  It’s the lids on the cans!  It’s the fact that I have no idea what I’m doing and should really go back to school!

Wait a second.  I’m pretty sure that last one’s never come up.

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About The Amateur Scientist: Brian Thompson is a professor of amateur science at a major imaginary university and a regular blogger at CHUD. He has been able to read and write for over seventeen years.

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