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Number Six
28th January 2003, 08:55 AM
I'm having a discussion over the computer with someone that believes in dowsing. (Sadly, this person is also a medical doctor.) But this person isn't a True Believer so possibly I can make some headway. The problem that I don't know that much about the topic. (I didn't go searching for a dowsing discussion, it just kind of came up.) So he linked to a dowsing site and here is a passage from it that I need a critique of. Any thoughts are appreciated.

Water and Electricity

A simple science fair experiment can show that moving water can cause electricity to flow

Water drops moving down the wire will rake off enough electrons to flash a small neon bulb which requires over 68 volts. This is like you sliding across a plastic seat and experiencing an electric spark when you touch someone.

Moving water underground seems to cause or to be associated with electric flow. Any time electricity flows in any kind of conductor, it creates an electromagnetic field. This electromagnetic field could then be picked up by our internal sensors. And like the eye that can differentiate between forms, shades and colors, the magnetic sensors, at least according to dowsing, seem to differentiate between patterns of electromagnetic energy fields from different sources. Therefore, the subconscious can easily have information about the location of moving underground water.

pgwenthold
28th January 2003, 09:10 AM
Originally posted by Number Six
A simple science fair experiment can show that moving water can cause electricity to flow

Water drops moving down the wire will rake off enough electrons to flash a small neon bulb which requires over 68 volts. This is like you sliding across a plastic seat and experiencing an electric spark when you touch someone.

Moving water underground seems to cause or to be associated with electric flow. Any time electricity flows in any kind of conductor, it creates an electromagnetic field. This electromagnetic field could then be picked up by our internal sensors. And like the eye that can differentiate between forms, shades and colors, the magnetic sensors, at least according to dowsing, seem to differentiate between patterns of electromagnetic energy fields from different sources. Therefore, the subconscious can easily have information about the location of moving underground water.

Simple: if what they say is true, then it is testable. These people should be able to detect water in controlled circumstances. So far, any controlled study has failed. Hence, either there aren't any magnetic fields being generated, or the dowsers are unable to detect them.

Heck, according to the claims in this, there are lots of different studies that could be carried out to see if the person can detect magnetic fields.

As many will point out: it is meaningless to talk about a mechanism before the effect has been established.

arcticpenguin
28th January 2003, 09:15 AM
First of all, there is no point getting into involved discussion of HOW dowsing works, since it has never been shown TO work in a carefully controlled setting.

Here's some resources:

Skeptic's Dictionary (http://skepdic.com/dowsing.html)

Skeptical Inquirer (http://www.csicop.org/si/9901/dowsing.html)

You can also search on the JREF site (http://www.randi.org/), I'm sure Randi has mentioned dowsing from time to time in his weekly newsletter.

I know Randi has tested many dowsers, I don't recall whether there is a chapter on this in his book Flim-Flam! or not.

As for an internal electromagnetic sense in humans, I've never heard of such a thing. I know some migratory birds have been proven to be able to sense the Earth's magnetic field.

Underground water would certainly not be pure, but would be laden with minerals tht would make it a conductor, not an insulator. It would diffuse electric charges, not build them up.

Aoidoi
28th January 2003, 09:42 AM
In addition, if an EM field was generated it could be detected using numerous instruments rather than relying on some sort of unproven internal sense.

Idly, if people could feel EM fields why would they need the dowsing rod? How does the dowsing rod interface with the supposed sense? How can this combination detect something that far more sensitive electronics equipment cannot? How does the dowser differentiate fields?

And, of course, why doesn't it work in controlled experiments?

Personally, I think tossing EM into the explanation is just to give a veneer of reasonableness to it. Sounds good at first but doesn't really hold up under testing.

pgwenthold
28th January 2003, 09:58 AM
Originally posted by Aoidoi
In addition, if an EM field was generated it could be detected using numerous instruments rather than relying on some sort of unproven internal sense.

Idly, if people could feel EM fields why would they need the dowsing rod? How does the dowsing rod interface with the supposed sense? How can this combination detect something that far more sensitive electronics equipment cannot? How does the dowser differentiate fields?

Oh the answer to this is easy. The dowser is just so much more sensitive to the electric fields than the instruments.

Of course, if that is the case, something like local power lines or the computer monitor should knock them on the floor, but we won't worry about those details...

And, of course, why doesn't it work in controlled experiments?

Whoops!

Crossbow
28th January 2003, 10:06 AM
To: Number Six

If your doctor friend is so sure that his facts are right, try asking him where does all this stray electricity go when water is pushed through pipes, firehoses, or sent down river, or over water falls.

If his ideas were correct, there would be vast reservoirs of untapped electrical power circulating in moving water.

Boy, check out all those puns in the second sentence. Ooops! I might have spend some time in the punatentirary!

Goshawk
28th January 2003, 10:13 AM
Number Six, ask him: If people really are able to detect electromagnetic fields, then why don't we hear all the time that people can detect the common EMFs available around the house? Any time you turn on an electric appliance, it produces an EMF.

http://www.peninsula.wednet.edu/conservation/Energy/EMF_health_effects.htm
The committee focused on the health studies of low-frequency electric and magnetic fields common in homes. Sources of exposure include transmission and distribution lines and electric appliances, including shavers, hair dryers, video display terminals, and electric blankets.
Plugging a wire into an outlet creates electric fields in the air surrounding the appliance. The higher the voltage the stronger the field produced. Since the voltage can exist even when no current is flowing, the appliance does not have to be turned on for an electric field to exist in the room surrounding it.

Magnetic fields are created only when the electric current flows. Magnetic fields and electric fields then exist together in the room environment. The greater the current the stronger the magnetic field.A simple way to test whether humans could detect EMFs would be to take a test subject, put him in a room that was totally dark, and empty except for a a switched-on lamp with no bulb in the socket, and tell him to point to where the lamp was.

Or you could hang a turned-on electric blanket on one wall, and tell him to point to the wall with the blanket.

I've never heard of humans being able to do this.

If people can't even detect the EMFs available in their own homes, up close and personal, how could they be able to detect the EMF produced by water flowing 50 to 200 feet underground, sometimes through solid rock?

Jack of Hearts
28th January 2003, 10:39 AM
Originally posted by Number Six
...here is a passage from it that I need a critique of. Any thoughts are appreciated.

Water and Electricity

Moving water underground seems to cause or to be associated... Therefore, the subconscious can easily have information about the location of moving underground water.

Stop. HOLD IT RIGHT THERE.

Easy. Just point out to your friend that water, contrary to the illusions of many dowsers, DOES NOT FLOW UNDERGROUND in a vast network of underground rivers and streams. Most well water, I believe, comes from moisture present in the ground... and, in most places, there's quite a bit of it around.

I'm looking for a good, succinct link to this effect, if anyone has one... this is the best I've got so far:

http://www.lysator.liu.se/~rasmus/skepticism/dowsing.html

"First, ground water within reasonable drilling depth is present almost everywhere. Well, the dowser argues, the art is to find the little subterranean streams where the water won't be standing still. The key here is that if there is underground water, originally moving or not, this will start to flow in the direction of the drilling hole, just as it eventually does when one digs a hole in the sand on a beach. The dowser then fools himself to believe that he actually found an underground stream. Now it's time for him to go home and feel he did something great. I'd suggest that the dowser be asked to find a place where there is no water!"

John

fishbob
28th January 2003, 11:43 AM
Underground water flow is slow (slow as dirt), typically on the order of inches per day - so very little electrical charge could be generated. In addition, the groundwater is grounded (duh) - so any electrical charges are dissipated almost immediately. Also, in addition, other interferences (such as buried power lines, overhead power lines, water supply pipes, sewers, gas lines, chain link fences) produce electrical signals strong enough to mask the background (natural) electrical fields.

Groundwater is typically uniformly distributed across large areas, filling the pore space betweens the soil particles, not in 'underground rivers' (a minor exception is flooded caves in karst areas).

So a dowser picking one spot and claiming to have found water based on 'electrical fields' is bogus.

Jack of Hearts
28th January 2003, 12:10 PM
Wow! Thanks, fishbob! That's great information. May I ask if your expertise is amateur or professional (or both)?

John

Soapy Sam
28th January 2003, 03:32 PM
Water contains hydrogen nuclei, which do carry a charge and do respond to magnetic fields. A proton magnetometer works on that principle and can very successfully detect groundwater several metres down, but it is not passively detecting an ambient field. It applies a field and measures the emf caused as the field decays.

I would be interested to know if any dowser works by sensing an externally applied field, rather than by hunting for ambient em fields. I might find that slightly less incredible. (stress on "slightly"). The notion that humans can be sensitive to electromagnetic fields does, at first hearing, seem credible enough to resist automatic derision, but like most claims of mysterious biomagnetic effects the problem seems to be the immense difference between the sort of magnetic fields we encounter daily and the sort of level the dowser claims to detect.

Number Six- does your friend own a Walkman? Does he walk in circles when wearing it? Mobile phone? Problems walking under power lines? (I appreciate you don't say your friend claims ability, but you take the point).

There are several threads on magnetic fuel enhancers, water softeners, bracelets etc in the Forum archives. Suggest you search through them. Repeatedly what comes up is not that anyone is objecting to em effects in principle, but that the field strengths required are just never found in nature except in thunderstorms or MRI scanners.

I would generally agree with fishbob's comments on groundwater movement. Actually, it's easier to find localised underground water movement in an urban than a rural environment. Water pipes are far easier to find than underground rivers.

fishbob
28th January 2003, 04:43 PM
Soapy Sam sez:

Water contains hydrogen nuclei, which do carry a charge and do respond to magnetic fields. A proton magnetometer works on that principle and can very successfully detect groundwater several metres down, but it is not passively detecting an ambient field. It applies a field and measures the emf caused as the field decays.
______________________________________

Subsurface survey techniques look for changes in signal from one location to the next. Imagine that your proton magnetometer gizmo response is some number, say 4. As you take measurements across an areas, you keep getting 4s, sometimes 4.1, sometimes 3.9. How do you interpret this? Is there water or not? How far down? In permeable soil? Salty or clean?

What dowsers do is walk around a property and pick a precise spot and claim that this is the spot where the water is, this is where a well should be drilled. The way groundwater is distributed, any spot within a general area will likely be just as good a location for a well. Imagine a swimming pool filled with marbles, the water fills the spaces between the marbles.

The poor suckers that believe this stuff have just enough money to drill one well - so they pay a driller, and lo-and-behold, there is water, and they are convinced. If the driller moved over a hundred feet and drilled a second well, he would probably find water, at a similar depth, of similar quality. And a hundred feet further away, and so on.

Groundwater is hard to detect because it is distributed uniformly within an area, distributed uniformly because it is a liquid.

To Clavis: my profession.

Tez
28th January 2003, 06:06 PM
welcome fishbob. Thanks for the very informative replies...

Soapy Sam
28th January 2003, 07:06 PM
As fishbob says, what is generally looked for in surveys is a change of signal- a discontinuity or at least a significant gradient. If you look for fluid in an area of uniform subsurface porosity and permeability, you won't find much of a discontinuity. Some electric logging tools will give high readings for certain rock types, low for others- porosity logs / gamma ray logs/ gravity surveys etc., but again, in a uniform area you won't see much. That's why testing for water pipes is a lot easier than looking for underground rivers- there are lots more of them. I would always ask a dowser to find a water pipe- if he fails with that...

I'd like to hear a serious model of a mechanism from dowsers, so it can be tested. When people claim to "dowse" minerals / water / buried treasure by waving a pendulum over a map, we know right away they are talking nonsense.
When someone talks about detecting minute em signals, amplified by micro muscle movements, it's harder to convince a non-critical listener that this is equally unlikely. It sounds like it might make sense and people know that magnetometers work. They often fail to appreciate the point that subsurface geophysical tools usually require a major energy INPUT to get a significant measurement. There is no equivalent to that in dowsing.

If number six is trying to convince a medical doctor, he needs a rational argument. I think the absence of energy input is a good one.

MRC_Hans
29th January 2003, 05:01 AM
I'm an electronic engineer, so I can work at some of the claims:

Water and Electricity

A simple science fair experiment can show that moving water can cause electricity to flow

Water drops moving down the wire will rake off enough electrons to flash a small neon bulb which requires over 68 volts. This is like you sliding across a plastic seat and experiencing an electric spark when you touch someone.

That particular show requires the wire mentioned to be connected to a high voltage source. The drop of water is charged and delivers its charge to the neon bulb (which does require a rather high voltage but an infinitesimal amount of energy). Something like this is what generates lightning :eek:

Moving water underground seems to cause or to be associated with electric flow.

This, on the other hand is not supported by any evidence. Water in the ground (flowing or not) can conduct electricity, but it does not generate it.

Any time electricity flows in any kind of conductor, it creates an electromagnetic field.

Correct, but any electric current in water in the ground will need an external source, which does not exist in nature.

This electromagnetic field could then be picked up by our internal sensors.

Except that there is no field (see above). Except that no evidence exists that we have such sensors. Even if we have, they are much less sensitive than our measuring instruments, which cannot detect those fields.

And like the eye that can differentiate between forms, shades and colors, the magnetic sensors, at least according to dowsing, seem to differentiate between patterns of electromagnetic energy fields from different sources.

Except that there is only one kind of electromagnetic field. Except that it would have to come from an external source (human generated, since such things do not exist in nature) and would reflect the characteristics of the source, not the water deposit. Those characteristics could be AC, DC, direction or polarity, but still totally irrelevant to the water deposit.

Therefore, the subconscious can easily have information about the location of moving underground water.

Therefore, the above conclusion is built in the following premises:

1) Flowing water generates an electromagnetic field: FALSE

2) Human senses can detect otherwise undetectable electromagnetic fields: FALSE

3) Different sources can be discerned by different fields: FALSE

Therefore, the conclusion is easily determined as: FALSE

Cheers, Hans

arcticpenguin
29th January 2003, 11:32 AM
Hey,
Take a look at this gadget (http://www.cnn.com/2003/TECH/ptech/01/28/science.metaldetector.reut/index.html).

The hand-held Melodi (metal location and detection instrument) will also be able to locate bullets and shrapnel in the body and could save millions of dollars in reduced hospital costs, according to its developers.

"It's the first one of its kind that can locate metal in three dimensions with great accuracy," said Dr Paul Durrands, of Melodi Technologies Ltd.
...
Instead of using X-rays to find the object, Melodi will transmit weak magnetic signals and will detect a small change in the magnetic field to show metal objects lodged in human tissue. About the size of a coffee grinder, it requires no specialist training and is simply passed over the body.
A screen on the top of the device shows when it finds something and an arrow gives an indication of the depth and the orientation of the object.

fishbob
29th January 2003, 04:39 PM
There is a reasonable and testable expectation that this device might work because:

- There is good contrast between bits of metal and human intestinal works.
- The device transmits a signal and detects changes.

MRC_Hans
30th January 2003, 01:28 AM
Metal detection has NOTHING to do with dowsing. An active metal detector works on solid scientific principles; an AC magnetic field will be influenced by metal objects nearby and this change can be detected. Precisely locating small objects within a human body is complex, but surely possible.

It is also possible to build devices that can detect possible water sources in the ground, and oil and mineral sources. This is being done and they are being used for finding water pipes, underground cables, water sources, oil, and minerals. They are also being used for archaeologic research.

But dowsing claims that the HUMAN brain, mind, or whatever, can do this without any technical aids. For this claim there is neither theoretic nor empirical evidence.

Hans

Soapy Sam
30th January 2003, 03:24 AM
If there was anything to the dowser's EM field sensing theory, I would expect them to have much better results with some shallow ore bodies than with groundwater. Sounds like fishbob has had actual field experience with dowsers- any data on that?

Hans' comments underline the fact that an iron pipe with water flowing through it, especially in dry sand, should be the ideal dowsing target and is the obvious test to set up for any claimant. If he can find water, or ferrous metal, he should have no problem...

And it can be confirmed with a simple metal detector.

Dragonrock
30th January 2003, 01:05 PM
Sharks can detect electromagnetic fields, but only because they have organs called "ampullae of Lorenzini". Humans have nothing like this, so it's doubtful that humans can detect EM fields.

Here's some info on shark senses.

Shark senses (http://www.enchantedlearning.com/subjects/sharks/anatomy/Senses.shtml)

Soapy Sam
30th January 2003, 05:03 PM
Sharks can detect very weak EM effects. I'm sure we can all pick up really strong ones. Sticking your finger in a light socket often makes the eyes light up!

It's the opposite side of the "I'm sick because I live under a power line" story, isn't it? I wonder if sharks get headaches, blurred vision, general malaise and a sore back when they swim past a power line?

13th February 2003, 07:05 PM
Originally posted by arcticpenguin
Hey,
Take a look at this gadget (http://www.cnn.com/2003/TECH/ptech/01/28/science.metaldetector.reut/index.html).

This is based on very standard metal detector technology. All metal detectors transmit an EM field, and look for certain changes in either the original field, or a returned signal.

13th February 2003, 07:45 PM
Some other general observations (some repeats of prior posts):

Dowsers often claim they can detect electrostatic fields, magnetic fields, or electromagnetic (EM) fields. The last 2 are not the same. A magnetic field is static (Earth's, or a magnet); an EM field is generated from an alternating energy source, i.e. power lines, radio transmitters, light bulbs, etc.

Water in motion can theoretically generate a magnetic field, it's called magnetohydrodynamics.

Underground "streams" are a myth of dowsers, groundwater is actually held in rather static aquifers, and flows only inches per day.

Galvanic voltages can be produced in the ground under certain conditions, and can cause minute currents to flow, which will tend to choose the path of least resistance, such as water.

Magnetometers cannot detect metal or water. They only detect magnetic fields, and are usually used to look for anomalies, which can be caused by metal (iron or nickel), or water.

Some dowsers have taken a fancy to dowsing gadgets which employ EM signal generators. They believe that the signal will "resonate" with a desired target, and cause the rod(s) to swing. They like to believe it is similar to MRI technology.

It is fallacious to believe that, if a dowser claims he can dowse for groundwater, then some other test (such as pipes) should be easier. It is the skeptics who are looking for a test that's easier to administer, and this "easier" test may completely miss testing the dowsers "ability". Testing a groundwater dowser is difficult and expensive. Asking the dowser to do pipes instead, only provides him with a pre-packaged alibi when he fails, even if he initially agrees to the test.

bjornart
14th February 2003, 01:28 AM
Originally posted by TechHead
It is fallacious to believe that, if a dowser claims he can dowse for groundwater, then some other test (such as pipes) should be easier. It is the skeptics who are looking for a test that's easier to administer, and this "easier" test may completely miss testing the dowsers "ability". Testing a groundwater dowser is difficult and expensive. Asking the dowser to do pipes instead, only provides him with a pre-packaged alibi when he fails, even if he initially agrees to the test.

I agree with part of what you say, but... If he initially agrees, it's because he believes he can dowse for pipes as well. He has probably done so before with "great" results and, just like the skeptic, thinks it's easier to prove. (I could use equal opportunity pronouns here, but I like the illusion that women are somehow smarter than us men.) Afterwards he can go home and tell himself, and the world, that "Well, I was wrong about the pipes, but I still believe (or, more likely, know) I can dowse for ground water." And true-believers will accept that. For someone with even an ounce of skeptisism however this might spark the question, "If he was that much off on the belief that he could dowse for pipes, what's the chance that he's equally wrong about groundwater dowsing?"

Converting the true believers is impossible (if you define a true believer as someone who can't be converted ;)), prodding a latent skeptic away from woo-woo-land is. As long as we remember that after a test of dowsing for pipes, ridiculing groundwater dowsing is fun :), not fact, we're doing a good job.

MRC_Hans
14th February 2003, 04:03 AM
In experimental science, much research is based on derived results. For example, we use particle accelerator experiments to infer about mechanisms in stars, since it is not practical (to say the least :cool: ) to experiment on stars.

Likewise, it is not unreasonable to test dowsing on controlable underground water, i.e. pipes, and infer from there to natural ground-water, as long as we realize the limitations of the test.

I agree with bjornart that the purpose of such experiments are not primarily to convince dowsers and their Believers (although such a result would be desirable), but to limit the proliferation of their follies, and to discourage them from claiming that their abilities are somehow "scientifically proven".

Hans

14th February 2003, 09:20 AM
bjornart does have a point, that simplified testing is useful in demonstrating the fallacy of dowsing to a fence-sitter. And he's right, a "true believer" will not be swayed, no matter what the test protocol. But a simplified pipe test has no value in testing the claims of a groundwater dowser, unless that dowser already equally claims the ability to locate pipes, and has done so in the past.

Let's suppose for a minute (and only a minute) that it really is possible to dowse for groundwater. Let's say that the physics behind it, is that large-scale aquifers displace enough magnetic minerals (maghemite, magnetite, etc) to cause a local deviation in the Earth's magnetic field, and that a very small handful of people out there can actually sense that deviation. Not knowing that is what's happening, they use a dowsing device, and subconsciously trigger it based on sensory input.

In that case, a pipe test is useless. It does not create the same conditions that cause success in groundwater dowsing. Again, the dowser does not know why he can dowse, or might have an erroneous notion, and when presented with an alternate pipe test, he might very well say, "Sure, sounds fair." At the end of the test, you can very well expect him to say, "It wasn't the same."

Pipe dowsing tests are useful for testing pipe dowsers, and somewhat useful in demonstrating the general fallacy of dowsing. I would argue that the latter case is most effective on large test groups, where the dowsers can see that everyone failed. Groundwater dowsing claims must be tested with a groundwater dowsing test, which is incredibly expensive, but would be very reasonable if it were done for a large group of dowsers. This is the test that I'd like to see performed.

DrMatt
14th February 2003, 09:26 AM
Originally posted by arcticpenguin

I know Randi has tested many dowsers, I don't recall whether there is a chapter on this in his book Flim-Flam! or not.

Yes. There's a chapter devoted to his double-blind test of the best dowsers of Italy. All of them thought they'd passed the test. All bombed royally.

This leaves us with the phenomenon of belief in dowsing, in light of it having no better than chance effectiveness.
I think Randi's book gives some pretty plausible explanations for that, too.

14th February 2003, 11:13 AM
And don't forget the single biggest dowsing test ever conducted, the "Scheunen" test by Betz & Co, with literally hundreds of dowsers. Jim Enright's analysis of the data clearly shows what the outcome really was. Don't think Randi mentions this test very often, not sure why.

Dragonrock
14th February 2003, 11:17 AM
Originally posted by TechHead
And don't forget the single biggest dowsing test ever conducted, the "Scheunen" test by Betz & Co, with literally hundreds of dowsers. Jim Enright's analysis of the data clearly shows what the outcome really was. Don't think Randi mentions this test very often, not sure why.

OK, I'll bite, what was the outcome?

14th February 2003, 09:14 PM
Let's suppose for a minute (and only a minute) that it really is possible to dowse for groundwater. Let's say that the physics behind it, is that large-scale aquifers displace enough magnetic minerals (maghemite, magnetite, etc) to cause a local deviation in the Earth's magnetic field, and that a very small handful of people out there can actually sense that deviation. Not knowing that is what's happening, they use a dowsing device, and subconsciously trigger it based on sensory input.

In that case, a pipe test is useless. It does not create the same conditions that cause success in groundwater dowsing. Again, the dowser does not know why he can dowse, or might have an erroneous notion, and when presented with an alternate pipe test, he might very well say, "Sure, sounds fair." At the end of the test, you can very well expect him to say, "It wasn't the same."

But you are leaving out an important point. Before the blind portion of the testing starts, the dowsers are allowed to "calibrate" their dowsing powers by walking across the test area while the water-filled pipes are labeled. The testing continues only if the dowsers say they can detect it when they know where it is. If the large-scale aquifer theory were correct, then the dowsers who claim success when the water-filled pipes are marked are really fooling themselves. The case then boils down to are they fooling themselves all the time, or are they fooling themselves only when dowsing for marked pipes and they are accurate when looking for aquifers? The latter seems to me to require an unecessary multiplying of entities (that's easier than trying to spell his name.).

NWilner
16th February 2003, 06:46 PM
Looking at the dousing epiphenomenon, I would wonder:

1. Is there empirical evidence for it?

2. Is there a physically plausible theory or mechanism?

As to #1, the evidence seems to be at best anecdotal, although I haven't surveyed the epidemiology. Negative studies are not necessarily conclusive. Even one positive study would suggest further work. Are there such?

As to #2, I would suggest absence of a mechanism is not in itself a firm argument against existence if #1 is otherwise satisfied. But I'm not aware that any plausible mechanism has been advanced.

One possible mechanism would be, the skill and judgment of the douser, who uses subtle information about the soil type, topography, and patterns of flora to predict underground water. Since an "experienced" douser would have been present at more well drillings than the average person, he or she may have developed powers of observation of these and other subtle above-ground clues.

Then again, if there is no performance beyond chance, there is nothing to explain.