What is A Cold Spot
By Mark Stewart
8-4-2007
Cold spots have often been reported in locations thought to be haunted. Cold spots are small areas (usually a lot
smaller than a room) that feel significantly colder than the surrounding area. They are considered by some to be a
sign of a ghost in the area. Some cold spots are always felt in the same place while others seem to appear and
disappear at different locations.
When thermometers are placed in rooms where cold spots are reported they generally fail to register any drop in
temperature. What is more, only certain people seem to feel these cold spots. Others can stand in the same place
and feel nothing. Some people see this as a sign of a paranormal origin with some people more 'sensitive' than
others. Others see it as a sign that cold spots are purely subjective. However, there is another possibility! There are
natural phenomena that have a real physiological effect on someone without a change in the air temperature.
Draughts are the obvious example but there are others.
Draughts and Convection
Air is almost always on the move in a room, even with the door and windows closed. This is because the surfaces of
some objects are at different temperatures to others. Heat will be exchanged between the objects in an attempt to
equalize the temperature. This is done mainly through convection. This is an airflow whereby warm air (which is less
dense) rises towards the ceiling; cools and drops back towards the floor.
There is obviously even more scope for draughts where the room connects to other areas as for example through
an open door, window, hatch, fireplace or gaps in draught-proofing.
When moving air is in contact with human skin it will generally feel cool (wind-chill). This is because the moving air
removes heat from the skin. It also cools by causing evaporation from the skin. This cooling will NOT show up as a
temperature drop with a conventional thermometer.
Suggestion: Never underestimate the power of suggestion. Tell someone that they are standing in the 'cold spot'
and they may start feeling it! It is best not to tell anyone where the cold spots are supposed to be and then see if
anyone reports one.
Some people suggest that the coldness of a cold spot indicates that heat has been abstracted for some paranormal
process. If so, it is curious because heat is about the worst source of energy you could choose.
Radiative Heat Loss
Though it is less obvious than convection, cold spots can also be created by radiative heat loss. When you stand
directly in front of an electric fire or radiator, you will feel heat. Less well known is that people can LOSE heat in the
same manner. If you stand directly in front of a cold object, such as an un-curtained window on a cold night, you will
feel colder. Your body is radiating heat in all directions. However, it will radiate more, to maintain its temperature, in
the direction of cold objects. This additional loss of heat will be felt as cooling. Generally, you need to be quite close
to a cool object to get the radiative loss. Like a heater, if there is anything between you and cool object, you may not
feel the effect. Like convection, a conventional thermometer will not register this apparent temperature drop.
Measuring a Cold Spot
The most obvious cause of a cold spot is a drop in air temperature. So the first thing you need on a vigil is a
thermometer. The ideal set up would be an array of small thermal sensors placed in a grid to precisely locate any
cold spot.
To spot convection you'll need an anemometer to measure wind speed. Some instruments can measure wind-chill
directly.
To measure the temperature of cold surfaces you can use a 'point and shoot' infrared thermometer. However, be
aware that there are various issues with these instruments that can cause inaccurate readings. For instance,
different surfaces can appear to have different temperatures purely due to the color they are painted. This is called
emissivity. Also, most IR thermometers indicate the surface they are measuring with a laser dot. However, the area
measured is wider than this and varies according to the distance of the surface.
One of the most popular instruments used on ghost hunts is the thermometer. This is probably because it is easy to
obtain and cheap. Also, haunted places often produce thermal anomalies such as cold spots.
As with so many other technological developments, electronic versions have, to a large extent, replaced the
traditional mercury thermometer. One particularly popular variation is the laser (or infrared) thermometer. This
unique instrument measures temperatures remotely, which means that you just point it at an object and it indicates
its surface temperature.
By first appearance the infrared thermometer is a convenient device for vigils, particularly to get into areas that
cannot be directly reached. However, as with all instruments, you need to understand how it works to avoid possible
pitfalls.
The infrared thermometer, like all the devices used on vigils, was not designed for ghost hunting! It is primarily an
industrial tool. It works by measuring the black body radiation emitted by a remote object. Black body radiation is
radiation with the same energy density in each wavelength range as the radiation emitted from a totally absorbing
heated body. This wavelength of this radiation is related to the temperature of the object. It does not pick up the
temperature of the air between the object and thermometer.
The IR (infrared) thermometer views an area proportional to the distance from the thermometer. So, it can be
difficult for operators to know how much surface is actually covered when temperatures are sampled.
Another problem is that surfaces can produce different readings according to its emissivity (how shiny they are).
Portable IR thermometers are only accurate to within a degree or two in any case. They CAN be useful but consider
their problems and don't overestimate their accuracy.
By Mark Stewart
8-4-2007
Cold spots have often been reported in locations thought to be haunted. Cold spots are small areas (usually a lot
smaller than a room) that feel significantly colder than the surrounding area. They are considered by some to be a
sign of a ghost in the area. Some cold spots are always felt in the same place while others seem to appear and
disappear at different locations.
When thermometers are placed in rooms where cold spots are reported they generally fail to register any drop in
temperature. What is more, only certain people seem to feel these cold spots. Others can stand in the same place
and feel nothing. Some people see this as a sign of a paranormal origin with some people more 'sensitive' than
others. Others see it as a sign that cold spots are purely subjective. However, there is another possibility! There are
natural phenomena that have a real physiological effect on someone without a change in the air temperature.
Draughts are the obvious example but there are others.
Draughts and Convection
Air is almost always on the move in a room, even with the door and windows closed. This is because the surfaces of
some objects are at different temperatures to others. Heat will be exchanged between the objects in an attempt to
equalize the temperature. This is done mainly through convection. This is an airflow whereby warm air (which is less
dense) rises towards the ceiling; cools and drops back towards the floor.
There is obviously even more scope for draughts where the room connects to other areas as for example through
an open door, window, hatch, fireplace or gaps in draught-proofing.
When moving air is in contact with human skin it will generally feel cool (wind-chill). This is because the moving air
removes heat from the skin. It also cools by causing evaporation from the skin. This cooling will NOT show up as a
temperature drop with a conventional thermometer.
Suggestion: Never underestimate the power of suggestion. Tell someone that they are standing in the 'cold spot'
and they may start feeling it! It is best not to tell anyone where the cold spots are supposed to be and then see if
anyone reports one.
Some people suggest that the coldness of a cold spot indicates that heat has been abstracted for some paranormal
process. If so, it is curious because heat is about the worst source of energy you could choose.
Radiative Heat Loss
Though it is less obvious than convection, cold spots can also be created by radiative heat loss. When you stand
directly in front of an electric fire or radiator, you will feel heat. Less well known is that people can LOSE heat in the
same manner. If you stand directly in front of a cold object, such as an un-curtained window on a cold night, you will
feel colder. Your body is radiating heat in all directions. However, it will radiate more, to maintain its temperature, in
the direction of cold objects. This additional loss of heat will be felt as cooling. Generally, you need to be quite close
to a cool object to get the radiative loss. Like a heater, if there is anything between you and cool object, you may not
feel the effect. Like convection, a conventional thermometer will not register this apparent temperature drop.
Measuring a Cold Spot
The most obvious cause of a cold spot is a drop in air temperature. So the first thing you need on a vigil is a
thermometer. The ideal set up would be an array of small thermal sensors placed in a grid to precisely locate any
cold spot.
To spot convection you'll need an anemometer to measure wind speed. Some instruments can measure wind-chill
directly.
To measure the temperature of cold surfaces you can use a 'point and shoot' infrared thermometer. However, be
aware that there are various issues with these instruments that can cause inaccurate readings. For instance,
different surfaces can appear to have different temperatures purely due to the color they are painted. This is called
emissivity. Also, most IR thermometers indicate the surface they are measuring with a laser dot. However, the area
measured is wider than this and varies according to the distance of the surface.
One of the most popular instruments used on ghost hunts is the thermometer. This is probably because it is easy to
obtain and cheap. Also, haunted places often produce thermal anomalies such as cold spots.
As with so many other technological developments, electronic versions have, to a large extent, replaced the
traditional mercury thermometer. One particularly popular variation is the laser (or infrared) thermometer. This
unique instrument measures temperatures remotely, which means that you just point it at an object and it indicates
its surface temperature.
By first appearance the infrared thermometer is a convenient device for vigils, particularly to get into areas that
cannot be directly reached. However, as with all instruments, you need to understand how it works to avoid possible
pitfalls.
The infrared thermometer, like all the devices used on vigils, was not designed for ghost hunting! It is primarily an
industrial tool. It works by measuring the black body radiation emitted by a remote object. Black body radiation is
radiation with the same energy density in each wavelength range as the radiation emitted from a totally absorbing
heated body. This wavelength of this radiation is related to the temperature of the object. It does not pick up the
temperature of the air between the object and thermometer.
The IR (infrared) thermometer views an area proportional to the distance from the thermometer. So, it can be
difficult for operators to know how much surface is actually covered when temperatures are sampled.
Another problem is that surfaces can produce different readings according to its emissivity (how shiny they are).
Portable IR thermometers are only accurate to within a degree or two in any case. They CAN be useful but consider
their problems and don't overestimate their accuracy.
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