The Skeptical Teacher

Musings of a science teacher & skeptic in an age of woo.

Skeptical Psychic Fair in Chicago a Hit & How Ouija Boards Fail

Posted by mattusmaximus on August 1, 2010

On Friday, July 23rd, the Women Thinking Free Foundation held a skeptical psychic fair in Chicago as a fundraiser while also having some fun exposing the various tricks & techniques that go into all manner of psychic nonsense.

Among all the drinking & merriment, there were a number activities that we had, including a tarot card silent auction, a “psychic showdown”, along with some fun mentalism & magic tricks.  We also handed out many copies of Michael Shermer’s Learn to be Psychic in 10 Easy Lessons! which outlines the tricks of the psychic trade, including such time-honored (and completely NON-paranormal) techniques such as cold reading.

My primary contribution to the event was to bring a Ouija board to demonstrate a lesson in critical thinking regarding these supposed “spirit boards”…

The whole trick behind the standard operation of a Ouija board is a well-documented & understood phenomenon called the ideomotor effect, whereby the people holding their hands on the pointer of the board (the planchette) subconsciously maneuver it around without necessarily knowing it.  In fact, with Ouija boards, tests have been performed that illustrate that when the people using the board are blindfolded, and the board is randomly rotated without their knowledge, then all the supposed messages from the “spirit world” turn into gibberish.  Just take a look at this footage from Penn & Teller’s Bullshit where they tested a Ouija board in just this manner… 🙂

The ideomotor effect also explains why so many people fool themselves into thinking that dowsing works (or, as is more often the case, doesn’t work) various divination devices such as dowsing rods or a crystal pendulum (another demonstration at our event).

My particular twist on the Ouija board demonstrates a very cool aspect of physics.  What I do is use a “special planchette” which is a silvery disc of metal – the participant in the demonstration picks up this disc and waves it back & forth a few millimeters above the board while various eerie invocations are made.  The result: the “spirits” of the board tug & pull on the disc – the more the user pushes & pulls the disc, the more the “spirits” react.  In fact, one can even drop the disc and it will settle down onto the board slowly and gently as opposed to falling freely under the influence of gravity!!!

But here’s the upshot, and where the critical thinking, come in: I then remove the board to reveal a thick slab of copper metal underneath, and I tell the participant to repeat the demonstration.  The results are exactly the same!  Thus, through a simple application of Occam’s Razor, one can easily conclude the obvious: the Ouija board has nothing to do with the observed phenomenon.

So what’s going on?  Well, as I stated earlier, this is a demonstration of well-known physics, specifically two related phenomena called electromagnetic induction & magnetic braking via eddy currents. It all has to do with the interaction between my “special planchette” (actually a powerful neodymium magnet) and the copper beneath it.  Check out this Youtube video of me performing this demonstration (without the Ouija board) along with the written explanation…

On March 16, 2010, I attended a meeting of Physics Northwest (PNW) where I presented one of the demonstrations I use to illustrate electromagnetic induction & magnetic braking. You take a large slab of high-conductivity, oxygen-free copper (mine is 10 inches in diameter & 1 inch thick) and place a very strong neodymium magnet atop it (my magnet is one from As the magnet moves in the vicinity of the copper conductor, there is a changing magnetic flux through the copper which – in accordance with Faraday’s Law – will induce eddy currents within the copper disk. These eddy currents then interact with the magnetic field of the magnet, producing – through the right(left)-hand-rule – a force which opposes the original motion of the magnet.

For added physics pizzaz, we added in some liquid nitrogen. The LN2 cools down the copper, reducing its electrical resistance and allowing there to be a much larger induced current in the disk. The increased current then leads to much larger magnetic braking forces. This leads to all manner of really awesome effects, many of which seem almost magical if the observer doesn’t understand the underlying physics. Even for someone who *does* understand the physics, it’s still pretty awesome. This is one of the best demos I do all year, and my students are always excited to play with the setup!

By the way, in keeping up with the 21st century, there is now a version of the Ouija board for the iPhone or iPod-Touch – and, just for reference, it works on exactly the same principle as the original: the ideomotor effect, no “spirits” required.

6 Responses to “Skeptical Psychic Fair in Chicago a Hit & How Ouija Boards Fail”

  1. Ticktock said

    I’m interested in the mystery of Patience Worth. It’s one of my favorite stories of mysticism that I’ve yet to see debunked. I wish someone skeptical would do a thorough investigation.

  2. Okay. Let’s take it from the top. If the Ouija® Board really does work via the ideomotor effect, then it is stating things buried deep within the mind of the operator and WE SHOULD PAY ATTENTION TO THAT. Do you think it is of no import to communicate directly with your unconscious/subconscious mind? I think it is important. You seem to think it is a “trick.” But by your own definition the mind speaks through the fingertips. That’s powerful!
    Now… I have use “talking boards” with a wheel that spins. Where it stops is the letter used. I have had utterly amazing and accurate answers with such a device. Where does your precious ideomotor effect fit in there?
    Finally, don’t fall for the Penn & Teller schtick. If the show is called BULLSHIT, you cannot expect them to actually verify something. Besides, James “Amazing Randi” Zwinge is moribund, as id Penn & Telller’s career. They need to replace him to keep going and avoid actual work. Get it? They are merely positioning themselves with a group so gullible that Randi is able to pay himself $250,000 a year at his “foundation” FROM THEIR CONTRIBUTIONS! Why let a group of fish like that off the hook?
    There’s way more to this planet than the “skeptic” or “doubter” will ever know. It takes them out of their comfort zone. I know. I have done it with my own demonstrations many times. Go ahead, look at my site.

    • mattusmaximus said

      If there really is something to your spinning “talking boards”, then I suggest you apply for the Million Dollar Challenge to have it tested out or try writing up an article about it and submit it to a peer-reviewed, professional psychology journal. As for understanding or learning more about the subconscious, I’m more inclined to go with the latest scientific research by the psychological community.

      Btw, I did look at your website. I think you really need to get a professional website designer working on that because it is poorly put together – just some constructive criticism.

  3. […] (AAPT).  What I did differently is to add a number of skeptically-oriented twists to it, such as why Ouija boards don’t work and why “ghost-hunters” are full of hooey when they claim EMF meters are detecting […]

  4. […] might interest those of you in the Midwest next weekend: another Un-Psychic Fair!  You may recall the first WTFF Un-Psychic Fair in Chicago last year, and we hope that this one will be even more fun, more skeptic-y, and more un-psychic-y!!!  Read […]

  5. […] Ouija Board – At the link is a blog post I wrote on a lesson I use involving magnetic fields to get […]

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