Ghost Hunting Tools of the Trade

Why the use of electronic equipment by TV ghost hunters is so stupid.

by Brian Dunning

Filed under Paranormal

Skeptoid #81
January 1, 2008
Podcast transcript | Listen | Subscribe

Television shows about ghost hunting have been popular for over 50 years, and though the basic concept is the same, recent decades have seen the hunt become less about psychics and séances and more about electronic detection gear. Just about every TV show about ghost hunting sends a crew of investigators into a building, armed to the teeth with all sorts of equipment.

The use of any kind of measuring equipment to detect ghosts is fundamentally, and completely, bogus. How can I make a blanket statement like that? Measuring equipment detects what it is designed to detect, whether that's light, heat, electromagnetism, or whatever. Thus it will only detect things that emit measurable amounts of those energies. For us as viewers to accept that some piece of handheld measuring equipment has a useful function in detecting a ghost, we must base our acceptance on the premise that ghosts are known to emit those types of energies in measurable amounts. If there were any truth to this, science would have discovered it long ago. Hospital operating rooms would have ghost detection equipment built in. Mortuaries and crematoriums would have ghost detection equipment at the top of their list. Search and rescue crews would use ghost detection equipment. If ghosts did exist and were detectable, you can bet that there would be huge industries behind it. I can't think of anything that would attract more venture capital dollars from Silicon Valley. However, no rigorous research has ever shown that ghosts can be reliably detected with hardware. It's easy to disbelieve me, but it's much harder to disbelieve the lack of interest from greedy corporate America.

So now let's look at the popular tools of the trade of ghost hunting. The important takeaway is to understand what these devices are actually detecting when the ghost hunters point them around the room, and why their crazily jumping needles and indicators are perfectly consistent with, and explained by, the absence of ghosts.

Infrared thermometers are the most blatantly misused of the ghost hunting tools, so are a great place to start. These handheld devices measure the temperature of the object they are pointed at. They work exactly like your vision, except that they are sensitive to far infrared instead of the visible spectrum. They measure surface temperatures, just like your vision measures surface colors. If you can see something, an IR thermometer can measure its temperature. However, ghost hunters use these devices to detect what they believe are cold spots in rooms. IR thermometers are not capable of detecting something without a visible surface. In fact, an IR thermometer is even less likely than your vision to see a hazy apparition. Firefighters use infrared because the longer wavelengths of infrared penetrate smoke more effectively than the shorter wavelength of visible light; so if there were a hazy invisible apparition floating in the middle of the room, infrared is perhaps the worst technology to detect it. Variations of IR readings inside a room are merely showing temperature gradations on the walls, caused by heating and AC, insulation variances, studs, wiring, or pipes behind the wall, radiant heat, recent proximity of another ghost hunter, sunlight, temperatures in adjacent rooms, or countless other causes.

Infrared motion detectors work on the same principle. If the amount of IR radiation striking the sensor changes, an alarm can be activated. Such a change is caused by a sudden change in temperature within the detector's field of view, or a significant movement by an object with a visible IR signature. A ghostly cold spot moving within a room could not be detected, unless it also cooled the walls or floors enough to trip the activation threshold.

Particle detectors are devices that measure ionizing radiation. The most common particle detectors are Geiger counters, also called halogen counters. These work by measuring cascade effects caused by incoming particles that strike molecules of halogen gas inside the detection chamber. Typically, alpha, beta, and gamma particles are detected by these. It's not the most common of ghost hunting tools, but occasionally you will see someone pointing a Geiger counter around the room, though you may hear them describe it by any of several fancier and more high-tech sounding names. It's a Geiger counter. For a ghost to emit ionizing radiation, it would have to be an awfully sick ghost; or be composed largely of unstable radioactive metals. Ionizing particles don't just appear out of thin air, they are emitted by the decay of unstable isotopes that are typically heavy and have significant mass.

EMF meters are perhaps the favorite tools. EMF meters detect electromagnetic fields, and are used in ghost hunting on the premise that ghosts emit electromagnetism, though this claim is rarely supported by any suggestion of what the power source might be. There are many different types of EMF meters. More affordable units, such as those typically used by television performers, need to be held precisely for a period of time at each of the three axis to get a reading, and so they are clearly not used on television in a manner that would produce any useful result. When they are, or when a more expensive three-axis meter is used, they are designed to detect the operation of electrical appliances or wiring. Ghost hunters are usually thoroughly accessorized with every electronic gizmo under the sun: radios, cell phones, flashlights, cameras, TV cameras, and other ghost hunting accessories; and all of these will produce a result on the EMF meter. Building wiring or appliances will also be detected. But, even in an environment with no electrical devices at all, the presence of the TV camera alone renders the EMF readings totally useless. Even without ghost hunting equipment, electrical wiring, or a TV camera, a sensitive meter can even detect the oscillation of a steel filing cabinet vibrated imperceptibly by footsteps. In the midst of all the absurd amounts of EMF pollution on a TV ghost hunting set, the pretense that the alleged EMF field of a ghost (who's not carrying any batteries) can be identified, is foolish.

Ion detectors are interesting animals. The few commercially available ion detectors are available online almost exclusively through ghost hunting and alternative wellness web sites, which gives some clue of how useful they actually are. Ions occur naturally in the atmosphere from a variety of sources: solar radiation and weather being the main ones. Also, if you go to a part of the country where radon gas is an issue, an ion detector taken into the basement can go crazy sensing airborne ions created by radon decay. Ghost hunters prefer to regard this reading as indicative of the presence of a ghost. Ion detectors can also sense the presence of static electricity, so if your ghost is carrying a large static charge, you ought to be able to see it scuffing its shoes across the carpet.

Cameras of different types are used by ghost hunters. Sometimes they'll take a conventional visible spectrum camera and snap away, in the hope that spirit orbs or other manifestations will appear on the processed film. Since this phenomenon has already been thoroughly discussed in our episode on orbs, there's no need to repeat it here. Suffice it to say that all such images are well established artifacts of photography and of cameras, and well understood by knowledgeable photographers. They happen every day in photographs that have nothing to do with ghosts. Near infrared photography is the monochromatic "night shot" video that you see all the time, and that your home video camera probably offers. The light source is an infrared bulb on the camera, similar to the invisible light source inside your TV remote. These cameras record only what near infrared light is reflected from the subject, and of course they also record other near infrared sources, which are relatively common. Far infrared photography is the thermal imaging discussed previously. It's simply a visual display of the same heat sources detected by IR thermometers and motion detectors.

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Dowsing rods are probably the least controversial of ghost hunting tools, in that increasingly few people accept that they have any useful function. Yet ghost hunters still employ them. And why not? A self-described psychic's untestable verbal reports are under the psychic's complete control. They cannot be tested, measured, or duplicated by others — they say only exactly whatever the psychic wants to say. Dowsing rods simply give the dowsers another way to communicate whatever they choose to communicate. Since the rods are held in the dowser's own hand, they move only when the dowser wants them to move, and do not move when the dowser doesn't want them to. No form of dowsing has ever passed any type of controlled test, and no dowser has ever proposed any plausible hypothesis suggesting that dowsing might be an actual phenomenon. It is among the most childish of pretended ghost detection methods. The only thing you can learn from dowsing is which way the dowser wants to swing his dowsing rods.

Audio recording gear is used when the ghost hunter hopes that EVP. or electronic voice phenomena, will appear on the recording. EVP's are discussed often enough to warrant their own Skeptoid episode, and we'll be discussing them in detail in the future. An EVP is said to be the voice of a ghost, and the claim is that ghosts can talk perfectly well but can only be heard on an electronic recording. This means that recording gear has the ability to convert inaudible frequencies into audible ones. Engineers do not design this capability into most recording gear, since a change of frequency of perhaps tens of thousands of hertz would render all recordings completely useless and horrible to listen to. So, like they tend to do with all the electronic gear they carry, ghost hunters completely misunderstand, misuse, and mischaracterize the functions of these instruments.

When you turn on the television and you watch people pointing their gizmos around the room, acting all dramatic and pretending to detect ghosts all around them, any intelligent adult should laugh out loud. Or better yet, change the channel. Of course an intelligent adult should be free to watch whatever they want, and that's fine — but one place I will draw the line is the point where you let your children watch one of those shows and allow them to accept the silly claims as fact. Watch it and enjoy it as entertainment, if you find those people truly engaging and clever enough to be entertaining; but please, explain to your kids the science behind what they're seeing. Or, as the case may be, the lack of science behind it.

Brian Dunning

© 2008 Skeptoid Media Copyright information

References & Further Reading

Barušs, Imants. "Failure to Replicate Electronic Voice Phenomenon." Journal of Scientific Exploration. 1 Jul. 2001, Volume 15, Number 3: 355-367.

Fraden, Jacob. Handbook of Modern Sensors: Physics, Designs, and Applications. New York: Springer Science + Business Media, Inc., 2004. 243-251.

Juliano, David. "Ghost Hunting 101." Ghost Hunting 101. The Shadowlands, 1 Jan. 2009. Web. 2 Nov. 2009. <>

Knoll, Glenn F. Radiation Detection and Measurement. New York: John Wiley and Sons, 2000. 29-57, 103-119, 201-215.

Lipták, Béla G. Instrument Engineer's Handbook: Process measurement and analysis. Stamford: CRC Press, 2003. 575-578.

Radford, B. "Ghost-Hunting Mistakes: Science and Pseudoscience in Ghost Investigations." Skeptical Inquirer. 1 Nov. 2010, Volume 34, Number 6.

Reference this article:
Dunning, B. "Ghost Hunting Tools of the Trade." Skeptoid Podcast. Skeptoid Media, 1 Jan 2008. Web. 9 Oct 2015. <>


10 most recent comments | Show all 239 comments

Brooke: what do you mean by 'a ghost'? People 'feel' things everywhere, they feel awe before a mountain range, they feel humble looking at the sky at night, they feel a bit wobbly walking through a graveyard in the dark - and what, exactly, does that prove? That people are susceptible to emotional drives from within themselves. A 'ghost'. however, has to have some kind of definition before we can talk about it. Is it the spirit of someone dead? Is it some subtle emanation from a particular place? Is it a spirit trying to move to the 'other side'? Is it a spirit condemned for all eternity to spew ectoplasm from its mouth and make raps on walls? Is it some whisp of past possibility forever doomed to wander? You see - no-one knows what you are talking about, because you don't. 'Ghost' is like 'zombie' or 'vampire' in our culture, just a meaningless shudder for us to chat about. You must first tell me what can survive after death, then how it can assemble itself into some kind of perceptible form, then why the hell it might do that - and then I'll tell you you're a gullible fool.

Rob Horne, Colombo, SL
June 25, 2013 1:53pm

A ghost is assumed to be supernatural.

Its about 900 years since we all accepted that supernatural doesnt exist here.

I'd suggest getting them to wheedle out of the very tenets of their own religious statements...

Mud, sin city, Oz
August 2, 2013 5:22am

I went on a hike through a seaside forest years ago--the early 1970s. The day was hot and very, very humid, but my friend and I slogged through it nevertheless. We were taking photographs; I was using an old Argus SLR camera. I developed the 35mm B&W film myself and was surprised to find the pictures ruined by lightning bolts across most of the scenes. I had, however, a book by Hans Holzer which included pictures like mine as proof of ghosts. I went to the library and pulled out a half-dozen books on photography and finally found that the damage was caused by static electricity, not ghostly spirits flitting through the pine trees. We were walking over open sand dunes and forested dunes, cameras slung over our shoulders, and as I said it was hot, upper 80s with humidity to match. (The rest of Holzer's pictures were easily debunked as double exposures or manipulation of negatives, the sort of tomfoolery you can't get with digital cameras.)

Nancy R, Marietta, GA
September 24, 2013 4:09pm


You're on the money, as the "lightning bolts" caused by static electricity undoubtedly came when you stripped the film from the camera before processing. It was probably in a drier environment when you did that. In my life as a newspaper reporter/photographer, I shot many thousands of pictures, but never had that occur. But I was aware of that possibility, so I always rewound the film gradually as to not cause the static electricity problem.

Dean Acheson, Minocqua, WI
September 26, 2013 5:12am

If you can't see it, it doesn't exist? I have had dreams of recently departed, one did give me the winning lottery number. I won a little bit because I didn't believe the dream. Now who's the fool?
You want proof? Well, let's see............., Cleveland, Ohioi
September 26, 2013 5:50am

I have been a paranormal investigator since the age of 16, i am 48 now. I have been poked, prodded, scratched, felt dizzy, been sick, and yes i have even seen a apparition. Yes it is my own personal experience's, but i have been with a group a few times, and we have all seen the same apparition. I have the utmost respect for everyone to have their own opinions, but yours is only an opinion, as their is so much out their that you obviously haven't experienced. And most of the time it dosn't take paranormal equipment to tell you that their is something around us, listen to your own feelings
But that is my opinion only :)

noby01, rockhampton
August 20, 2014 4:18am

This episode was not so much about whether ghosts really do exist as it was about some of the electronic "tools of the trade" that so called "ghost hunters" often use and how easily these tools will respond to things other than ghost. It also goes after the notion that a ghost would trigger such devices in the first place. I personally don't buy into this "ghost" thing as I have never experienced a ghost nor has anyone ever provided me with compelling evidence that they do exist. Surely, going into an old dark building and getting a reading on an EMF meter or a few extra clicks on a Geiger Counter or orbs on a digital photo is not convincing evidence that there are ghosts around.

Joffbaum, New York, NY
March 31, 2015 12:15pm

Thanks for this post and all your others regarding 'tools of the trade'. I do not believe in ghosts and am a skeptic in most things but I went on a 'ghost-tour' last night of an old building near where I live. The tickets were given to me, otherwise I wouldn't have gone. It was lots of fun but not scary at all. We were guided by truly genuine people (one was a city councillor in the building where it took place), albeit a little over-enthusiastic. She could 'see' ghosts everywhere, apparently. The emt-meters were fun when they went off as we were told they were ghost children running all over the place as they were excited to see us! I saw a rubber ball move slightly back and forth in an empty hallway, I saw the meters going off when questions were asked of the 'ghosts' or when they were asked to set them off, and I took part in a table-tilting exercise at the end of the evening. It was quite chilling to feel the table shift and move across the floor. In hindsight, we were set up to expect certain things such as cold spots, grumpy ghosts in certain rooms, smells, touches on the head and legs, hands being 'held' by ghost children etc. (I experienced none of these but others around me did). The photos we were shown were very convincing but they were only on the guide's laptop and all the ones on the website that I checked afterwards show nothing at all (and yet they are supposed to be 'great photos' of ghosts etc). All evidence was anecdotal and subjective but many believed it

tinkapuss, Australia
April 11, 2015 3:46am

As a paranormal investigator, I feel like I should comment on a few points to help clarify some things to the skeptics.
Mainstream science has largely ignored or scoffed at those who claim to have had a paranormal experience or they automatically assume the person has some sort of neurological disorder which is causing them to think they saw a ghost, which of course could be the explanation in some cases but to me it doesn't seem very scientific to assume that all paranormal activity is caused by something wrong in the brain.

Enter the world of the paranormal researcher. We use equipment designed for other purposes because those are the only option! No one knows what, if any kind of energy is emitted during paranormal activity, therefore we experiment with equipment to try and find out if there is a way of detecting ghosts. True paranormal investigators also use their equipment to look for a more logical explanation before assuming anything is paranormal.
TV shows like Ghost Hunters have popularized the use of these gadgets to the masses and sadly many new ghost hunting groups have formed simply because they think they know what to do because they watch the TV show. It's these people who are giving investigators a bad name.

Chris, Georgia USA
April 11, 2015 9:45am

What are these so-called ghost hunters trying to achieve? By definition a ghost (assuming such an entity exists, which I personally doubt very much) is supernatural. It is therefore non-material and doesn't consist of some form of radiation. Scientific instruments can only detect material matter and / or radiation. Using them to try and detect ghosts is pointless.

Alvin Hopper, Canberra
April 12, 2015 9:38am

Make a comment about this episode of Skeptoid (please try to keep it brief & to the point).

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