You're at a haunted location. You want to check to see if there might be a ghost around. So, what do you do? You whip out your trusty EMF meter. Why? Um... well... because everyone else does. As the old argument goes, "and if everyone jumped off a cliff, would you?"
EMF (a.k.a electromagnetic frequency, electromagnetic fluctuation) has become the must-have gadget for any "serious" investigator of paranormal phenomena. Most ghost hunters will tell you that these devices react to ghosts and spirits, which "give off higher readings" of electrical and magnetic energies. It's failproof and reliable. Right? Well, not really. But before you prepare the fire to burn me at the stake for "heretical nonsensical talk", take a moment to listen.
Our world is a noisy cacophony of electricity, magnetism, and waves (radiation, radio, round, microwaves, etc.), most of which we cannot see, hear, or sense. Some is man-made, some natural. If we could hear all the energy constantly around us, it might sound like rush hour traffic in New York City. And this is the world in which we try to fiddle with a Gauss meter (or EMF meter). Many people using these devices don't know what they're detecting. Cheap models cannot filter out natural energy from interference caused by our own technology. But to ask most investigators, they "work".
In reality, they don't. I'm sorry, but they don't. I don't even own one because I've experimented with them and found them about as useful in the pursuit of ghosts as a rubber ducky. Yes, they do indeed note fluctuations in energy on occasion, but in the chaos invisible to our senses, what's really happening? It is that power line or cell phone? Am I sitting on a meteorite? Or did the CIA just fly a covert plane overhead giving off powerful radio signals telling me to invest in the Bank of America? I just don't know.
The sad fact is there is no definitive correlation found between unexplained phenomena and EMF readings. Some say ghosts cause spikes. Others say powerful bursts of energy make us hallucinate. But each is just a guess. A thought. I've witnessed unexplainable sights, sounds, and smells while Gauss meters remained silent and inactive. I've seen them go wild while nothing out of the ordinary occurs. And you're trying to tell me that EMF and paranormal phenomena are connected? No, thank you; I'm not interested in that prime Florida swampland.
If I'm trying to pick up a toothpick, a magnet won't work no matter how hard I try. It doesn't mean the toothpick isn't there; it just means that the magnet isn't a valid method of detecting it. And that's largely how I view Gauss meters in the field. You'll pick up on something alright, but not a ghost. So, you say, what does work, you mean, cranky, pessimist? Well, I don't exactly know. That requires more experimentation. But we need to look beyond one possibility to make any headway. What about a Geiger counter, or a photometer?
And yes, there's a reason I suggest these gadgets. Research in telepathy, which might be related to "psychic experiences" and hauntings, has found that whatever mechanism is being used to convey information is not governed by electromagnetic principles. Psychometry works in shielded environs and Faraday cages. Whatever we're looking for lies outside the known particles, waves, etc. Perhaps it's like a photon, allowing it to be visible yet behave like a wave. Whatever the answer, it exists outside the box.
For an interesting piece of reading material, I suggest Steve Mizrach's The Superspectrum Hypothesis.