Many inexperienced investigators are using another very unscientific method learned from the famous plumbers on TV. The "Flashlight Experiment" or as we like to call it  "The Stupid Flashlight Trick" or "SFT" for short.

The theroy is you can now ask the spirit a series of questions and the ghost will answer by making the flashlight turn on or off in response to your questions.

The problem with this method is that when you take a simple circuit like that, and just barely unscrew the flashlight so that the contact between the bulb and the battery (or the connection in general) is just slightly broken, the charge can still jump across the gap and will do so on a fairly regular basis. And this is nothing surprising; the whole point of barely breaking the circuit is to make it ridiculously easy for the circuit to be reconnected by the slightest of movements including tempature changes and loud noises.

But because the charge will jump the gap, so to speak, based on a regular accumulation of potential  it becomes a matter of confirmation bias.

 If you look at a lot of the footage, the investigators keep asking for a sign, over and over, and then when the flashlight comes on (or turns off), it is automatically assumed that it is a response…even if it took several requests before something happened! So there’s a simple scientific principle that is at play here, combined with (at the very least) a desire to believe. Or, worse, a desire to make something look paranormal when it is known to be normal.

Usually you will hear the investigators tossing out random statements, and when the flashlight turns on, they accept that to mean that the statement that was made at that moment was true. In other words, there was no experimentation…it was assumed, right from the start, that an entity was there, that it could manipulate the flashlight, etc.

Even if we grant that this might still be paranormal, an investigator would have to use a specific protocol that would demonstrate that the typical, random fluctuations that come as a result of the physics I mentioned could not explain the results. In other words, a pattern of definitive response to specific requests would need to be established over a long enough time to eliminate, without a doubt, that it was random. Such as asking the same question more than once, establishing a response for both “yes” and “no” (so that lack of response could not be equated with an answer!), giving a set time for responses, and so forth.

It would become clear, very quickly, that there is no intelligent pattern taking place…just random patterns that they try and assign meaning to.

Read more on the subject HERE