The vision of a deceased person or creature is commonly referred to as a ghost or apparition. Sometimes there is only a sense of their presence, such as feeling of coldness or a scent that is present without logical explanation. Other apparitions may consist of slight touching or hearing a thumping noise maybe raps and knocks. The essence is that a discarnate entity is making contact with the living. However, it should be noted that not all apparitions are of the dead. There are numerous recorded accounts of the living appearing to others as themselves when they were, in fact, in another physical location. Ghosts can appear to be solid or as filmy white mists. A common characteristic is their ability to walk through walls. They are also known to cast shadows and many apparitions have been seen in mirrors.
 

Cold spots are small self-contained air pockets that feel colder than the ambient temperature, they have been recorded between 10-40 degrees lower than the ambient air. They are usually found in the location at the approximate time of a manifestation. Witnesses frequently describe cold spots, or relate that they felt a chill upon entering the area (of a manifestation). It is theorized that these cold spots are the result of the manifestation using the heat energy of the surrounding air as fuel.
 

Ectoplasm has been recorded as the substance seen oozing from ghosts/spirits which makes it possible for them to materialize and perform feats of telekinesis. Ectoplasm is often not visible to the naked eye but appears in photographs. This may be due to the fact that most cameras are more sensitive to the spirit world than most people. Or, it may be due to a number of physical factors having to do with reflection, refraction, film processing, and other natural phenomena usually ignored by the truly psychic.  
 

These are more like what we perceive ghosts to be. They are blankets of light or a mist. At times they are just hanging in mid air other times they seem to take shape. There is some thought that this could be ectoplasm, which is basically residue from ghost activity. In most cases it is just a mist, a blanket of moisture that travels in the air. Other things that create this effect are breath in cold air and cigarette smoke. Some mists could be considered apparitions if they take human shape.
 

Orbs can be described as the energy of a previous living person. It has been proven that energy does not cease to exist, it changes form. When we leave our physical bodies, only the physical body dies. The energy that was us, ie. our thinking being or soul just changes. This is what an orb is, the energy that left our physical bodies. It continues to exist, just in a different form.