Divining rods, oy vey!

[Dan Hintz]

The suggestion of "magnets" really frustrates me. Americans spend millions of dollars a year on pseudo-medicinal "cures" that are based on the "power of magnets" (eg - magnetic "healing bracelets", etc). None of these have any basis in fact whatsoever - but people have a specious understanding of the magnetic force, and are quick to credit it with things they don't understand.

I tried explaining this to my grandfather, who was a big proponent of said bracelets... I never got through to him. The best "unscientific" blip I've seen on these was someone placing a paperclip against the bracelet and it holds. Then a couple of sheets of paper were placed between the bracelet and the paper clip... the clip fell right off. The magnetic field was so weak when distanced from the bracelet by only a few sheets of paper, it was pretty strong unscientific proof that no field of any significant strength would likely penetrate even the epidermis, let alone into the major bloodstream. Given the distance squared dropoff of magnetic field strength, well... you make the call.

But people want to believe...

[Lee Schierer]

I've seen it work also. When I installed my geothermal system 35+ years ago, I needed a second well. A well driller came out and said we would find water anywhere on my property. So he drilled a hole where it was convenient to get his rig to. Guess what we hit water at 28 feet, but it was barely a trickle and would not have worked as a supply well. He agreed to drill another hole at a location of my choice.

I had a man that was know for his ability to find water come to my property. He had never been there before. He located my septic tank and the leach field and also indicated there was a water vein across one part of the yard. He had never been in my yard before and had no knowledge of where the septic tank lines and downspout drain lines were. He put four stakes in the ground about 18" apart and said to drill there. The driller hit water at 26' and couldn't pump it dry with a 1 Hp submersible pump.

My wife blind folded me and wandered me around the yard for about 10 minutes and then taking me over the spot he marked several times. Each time she did, the two bent wires I was holding would cross and then open back up as we moved away from the spot. I don't pretend to understand it, but I have seen it work.

I also know that the Marines used bent metal rods in Viet Nam to locate underground tunnels that the Viet Cong had dug.

[Jerome Hanby]

I think trying to explain dowsing scientifically is absurd. However it could be explained psychology. Operating the rods could serve to focus the attention and a subconscious recognition of some trait of the ground could trigger the "slip" to let the rods cross. That would explain why some old (read experienced) codger is the one it always seems to work for and why some fabricated study wouldn't work (no time for any tell tale signs to have developed).

On the other hand people believe all kinds of crap from their chance of winning a lottery to invisible men that live in the sky...

[Dave Anderson NH]

I thought I'd throw a bit of a red herring in here in response to Jeff's comment about Bernoulli's principle. If this explains why an airplane "lifts" based on differrential airflow, then why doesn't a plane flying upside down crash into the ground?

[Dan Hintz]

James Randi has a (still unclaimed) $1,000,000 prize for anyone who can conclusively prove that such things work... according to Wikipedia (which I had to use as I haven't read his book, but I follow his work), he "devotes 19 pages to comprehensive double-blind tests done in Italy which yielded results no better than chance". The fact that some dowsers prefer a specific type of tree to make their divining rods while others can make it "work" with nothing more than a coat hanger yet again lends a sense of "bogusality" (yeah, I just made that word up) to it all.

When it works, everyone's happy. When it doesn't work, they'll say "You're not digging deep enough", or "it's only a general location, you need to look at places surrounding where I marked." Tough to prove them wrong, because once you find what you're looking for, you stop looking! When the general water table is known for an area, you have a much greater than 50/50 chance of hitting gold. Again, I gotta go back to the double blind tests that show it as pure hokum.

[Jacob Reverb]

Dan,

I've seen it work. Two bent welding rods were used. They crossed over each other as they passed over the line.

Same here. In fact, my Dad used the method to find the soil pipe between our house and the septic tank when I was growing up.

Not sure how it works, but it definitely seems to work.

[John Coloccia]

I thought I'd throw a bit of a red herring in here in response to Jeff's comment about Bernoulli's principle. If this explains why an airplane "lifts" based on differrential airflow, then why doesn't a plane flying upside down crash into the ground?

Actually, it's a good question. Bernoulli's law let's airplanes fly in the same sense that energy makes a clock work...it's somewhat true but not really. Aircraft wings produce lift because of different pressures created mostly by the wing's angle of attack. This is why fully symmetrical wings cand fly, and why flat bottom airfoils can fly upside down (the Citabria immediately comes to mind, and I can assure you it flies quite happily with sky under the wheels!). Flat plates fly perfectly well too, as would a brick given enough speed and a way to stabilize it.

[Dan Hintz]

John,

To your point about bricks flying... wasn't one of the recent bombers defined that way, as a flying brick? If it wasn't for the electronic control systems making mods to the control surfaces something like 100 times a second, it would never make it off of the ground. It is designed to be inherently unstable, which means its maneuvering capability is greatly enhanced.




Also, I forgot about this story, but find it very apropos:
http://www.nytimes.com/2009/11/04/wo...04sensors.html
The sensor turned out to be nothing but a high-tech dowsing rod (or less)... but they swear it works!

[Andrew Pitonyak]

The problem is that no one ever remembers all the times that it doesn't work.

Not true.... I remember fail to find some buried drain lines that I needed to dig up. Wished it had worked, would have saved me some digging.

As for magnets.. It is recommended that pregnant women NOT use electric blankets, even if they do not plug them in because the generated magnetic field may affect fetus growth. Not so problematic in adults, however; at least not at the levels obtained from an electric blanket. With a large enough magnet, I can kill a full sized grizzly bear; if I can convince him to hold still and I can figure out how to lift it and drop it on him.

[Dan Hintz]

With a large enough magnet, I can kill a full sized grizzly bear

A loose-leaf binder comes in handy during times like this... a mean paper cut can make them bleed to death.

[Belinda Barfield]

Well, I believe you gentlemen have established a reasonable level of bogusality. I'm waiting for you to establish a reasonable level of hokumality.

[Dan Hintz]

Well now that you've joined the fray, Belinda, we expect the hokum to increase exponentially

[John Coloccia]

John,

To your point about bricks flying... wasn't one of the recent bombers defined that way, as a flying brick? If it wasn't for the electronic control systems making mods to the control surfaces something like 100 times a second, it would never make it off of the ground. It is designed to be inherently unstable, which means its maneuvering capability is greatly enhanced.




Also, I forgot about this story, but find it very apropos:
http://www.nytimes.com/2009/11/04/wo...04sensors.html
The sensor turned out to be nothing but a high-tech dowsing rod (or less)... but they swear it works!

Yes, we've been designing them unstable for some time now. It allows you to concentrate on things like payload, strength, speed, efficiency and stealth, without having to worry about someone actually having to control the thing. For a wonderful study on why aircraft fly, read "Stick and Rudder" by Wolfgang Langeweische ( I think I spelled that right!). Should be required reading for every pilot, though sadly I doubt it is. I was certainly strongly encouraged to read it.

Currently, the pilot is the weak link when considering maneuverability. We can only pull so many Gs for so long without passing out our modern aircraft can easily exceed that. Top class aerobatic aircraft are routinely stressed to +-10gs, but fir very short periods of time. I can comfortably handle around +6...at least I could when I was doing it every week. 6 is pretty intense. I can't do but just a little over -1 before I get VERY uncomfortable. +-10 is absolutely insane, even for short periods if time. I can't even imagine what that must be like. I think my eyeballs would pop.

[Dan Friedrichs]

I've heard a lot of people say that 'so and so scientists' has proven that this doesn't work, but I've never seen one of these 'blinded trials'.

Take a look at the wikipedia article on the topic:
http://en.wikipedia.org/wiki/Dowsing

There are several links to excellent studies like you requested, all of which prove that it's nothing but chance.


The problem is one of probability - you can blindfold yourself and wander around your yard (like Lee S. apparently did), but even if you do it for days on end and keep getting the same result, you aren't aware of the other person doing the same thing and consistently getting false results. In order to ascertain whether or not it actually "works", you need a large enough sample size, and even then, you can never be 100% sure. What the scientific establishment provides us is methods (like statistical analysis) that can tell us whether or not a result is significant. For instance, if you gave a new drug to 10 people, and all of them got better, did it work? You might say, "yes", but in reality, there was a chance that they would have all gotten better without the drug, a chance that placebo effect made them better, etc - without statistical analysis, you have no idea if the drug actually worked or not.

The same is true for dowsing, but even more complicated because of all the other factors (prediction effect, etc).

[jim mills]

FORE SALE: Divining rod, used, but fully tested and functional. $50 (comes with instructions)