A cold spot or a hot spot is what many researchers believe happens when a ghost is trying to manifest itself. The
idea of the cold spot is that the ghost is absorbing the ambient heat energy surrounding it, thus making that spot colder.
(obviously a hot spot would be the reverse)
The peltier effect is a good explanation of this. Physicist Jean Peltier discoverd the Peltrier Effect in 1834.
It can be described as this: when an electrical current passes between two dissimilar conductors, heat is either released
or absorbed, depending on the direction of the current. The amount of heat released or absorbed is directly proportional
to the strength of the current.
If, as we theorized earlier, paranormal activity is connected to EMF, than a moving EMF field would be accompanied by
temperature variations.
Recording temperature changes (along with EMF readings) is another scientific way of detecting the presence
of ghosts. It is a scientific fact that there has to be some form of energy present to alter the temperature.
Temperature does not change unless "something" is affecting it one way or the other. The theory is that ghosts absorb
light, emotional and heat energy causing the general area around that ghost to be several degrees cooler. There
are also hot spots recorded, which could be just the reverse affect occurring. Instead of soaking up the light and heat
the ghost is reflecting it back, causing the area to be warmer.