Time to Throw out your Thermometers?
You wouldn’t catch a self-respecting paranormal investigator, anywhere in the country, without some sort of temperature gauge. Dave Wood questions why everyone is bothering… 
Whether it’s an old fashioned mercury thermometer, a modern weather station, digital probe, spot thermometer or data logger – everyone has them in abundance. But why are we using them, and are they even measuring what we want them to?
One stock response is that the interaction between ‘ghost’ and human somehow involves a change in temperature. Overlooking the dearth of non-anecdotal evidence for this, let’s look into this further.
Some people theorise that spirit manifestations are marked by ‘cold spots’. Be that when someone ‘feels’ a cold spot it means there is a ghost around, or when registering a localised drop in temperature everyone should expect a spooky experience. Astute investigators might even be interested in whether a cold spot can be objectively verified (and attributed to something normal) or whether cold spots are internal, physiological events.
Whether you tread the path of woo, pseudo-science or rationalism, it all seems to come back to the idea of measuring a localised cold- (or indeed, hot-) spot. So do these temperature gauges do what we want them to do, do they measure localised cold spots? If you are thinking about whole rooms going cold for sustained periods of time, then temperature gauges are probably fairly useful. However if you were thinking of the localised and often time sensitive cold spot, then the story is rather different.
Old fashioned thermometers are notoriously unresponsive, so if you are measuring a brief change in temperature you probably should not use one of these. The same principle goes with digital thermometers, for example weather stations. If you were thinking of the spot thermometer, best think again. Hopefully everyone knows that these do not measure ambient temperature variations, merely the surface temperature of whatever surface (or person) is behind the cold spot. Data loggers might seem like a God-send for investigators concerned about consistency and human error, but the response rate on standard models is around twenty seconds. Perhaps not so useful, after all. Having said that, a new model available through the manufacturers will register a change of temperature within seconds, putting it on a responsively par with some models of digital probe.
So we have established that if you are looking for a meaningful quick response, new model data loggers and certain digital probes may work. The next stumbling block is that temperature gauges are localised to the area immediately surrounding the sensor. This means that unless the probe or logger is exactly where the cold spot is said to be, it will not be measured. Having a dedicated temperature taker on hand to rush to the location of the cold spot is not useful either. Even if they were to make it whilst the cold spot is still felt, the chances are that they will spend valuable seconds measuring the ‘wind speed’ temperature involved in rushing from A to B. This is further compounded by the fact that if you move any thermometer, responding to an 'experience', it will be scientifically unmeaningful as you will not know what the previous temperature was in that spot.
The only saving grace for temperature gauges might a labour and cost intensive one. Having at least one logger for each person may be a start, but it would have to be complemented by repeated grid surveys of the area to provide a baseline. Another alternative might be a thermal imaging camera - albeit not for ambient 'cold spots' - but these are beyond the cash flow of most investigators!
One thing we can be sure of is that keeping a temperature gauge hanging around on the off chance of capturing some unrepresentative, anecdotal evidence is not especially useful.