A ‘ghost story’ for engineers,

[Lee CooperParticipant @leecooper46013]

I quite enjoyed this little true story and thought some of you might appreciate it.

http://www.richardwiseman.com/resources/ghost-in-machine.pdf

[Dave HalfordParticipant @davehalford22513]

Especially given the month published ;O)

[Nigel Graham 2Participant @nigelgraham2]

Ooo-er… I am not sure reading that at eleven o’clock at night, a good idea!

Intriguing – acoustical effects like that could well account for some “ghosts”. Rather as hypnogogic dreams and related physiological events used to be thought psychic attacks – though they are still alarming.

Might we also consider two psychological effects, of opposite “polarity”?

1) Being alone in the situation. No-one to turn to, and possibly heightened senses. I have the impression the brain “turns up” our hearing and sense of touch (including of temperature on the skin) where these become the major ones. Such as in darkness, though that would not have been applicable in that laboratory.

2) In company: if two or more people together feel there is something uncanny they tend to reinforce each other’s fear.

 

On resonance, rooms and corridors have very low resonant frequencies inversely proportional to size; as the article examines. The nature of the sound is heavily dependent on many factors including absorbtion by sufaces and objects – including people – within it; but the frequency is calculable easily if the room is considered a plain cavity.

 

I have encountered this in a cave in Norway. Two of us had explored the steeply-descending tube about 2 – 3m diameter down to a solid choke of sand. Back up at the entrance, we sheltered just inside to await a rainstorm to pass (the cave did not take a stream). We noticed a steadily, slowly alternating draught – in, out, in, out. The wind blowing past the entrance was causing the cave air to resonate, like blowing across a bottle-top. I forget the approximate frequency, but we named the place, Pustehohle (Breathing Cave).

Back home, some research uncovered work done on this effect, in as I recall, Canada. There the draught was measured by a data-logger connected to a rotary potentiometer oscillated by a large, lightweight vane occupying most of the passage cross-section.

Using the same formulae to an apparent, approx. 20-minute period, breathing in a cave “dig” in the Mendip Hills, indicated the chamber yet to be found below the boulder choke we are trying to clear, would be too large to fit under that bit of countryside! I concluded the cavity was more brake-ejector than organ-pipe, by variations in the wind blowing across the vertical entrance shaft; not resonance. As the cleared volume increased the breathing largely disappeared, probably by a “smoothing capacitor” effect, and was replaced by a steady draught from… somewhere below!

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So where else might these “hauntings” occur? There was a bit of a do several years ago, with American diplomats in a country of uneasy relationship (Cuba?) blaming their hosts for apparent attacks hard to define. I wonder if they investigated their own building!

Most “ghost” tales are old enough to be from buildings with solid walls and bare floors, open chimneys, poor insulation, many draughts and patchy lighting; so prone to peculiar cold spots, mist patches, resonances and physiological effects unknown then, unexpected settlement or animal noises, and optical illusions.

 

The article’s introduction suggests many alarming phenomena from mundane effects. Back on Mendip one member brave enough to spend a night alone in our club-house, in windy weather, was awakened by slow, laboured breathing from a small, partioned-off store in the loft next to his bunk. Being of sterner stuff and having access to the keys, he entered the store and put the “ghost” to rest… by wedging the flapping edge of roofing-felt.

 

The more the Psychical Research people investigate, the less “psychic” they will have left to investigate!

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As for resonance… I do wish music presenters would learn the difference between a reverberant and resonant building, and between acoustic (adj.) and acoustics (n.)!

 

[Howard LewisParticipant @howardlewis46836]

When three car DMUs were first introduced by British Railways, passenger did not like being in the power cars m at station stops.

Investigation showed that, at idle, the 8 cylinder engines were causing the windows to vibrate at 20Hz.

Resetting the idle speed, only slightly, provided a cure!

20Hz maybe too low a frequency for many people to hear, but can have effects (as the reports shows) and be difficult to eliminate. High frequencies can be absorbed, but low frequencies have to be tuned out in some way. Stiffening is likely to bring the vibration onto the audible range, so very often the solution is to use something like very soft rubber mounts to bring the resonant frequency right down.

Having a resonant frequency within the running range of a machine can bring disaster in a very short time, (The dynamic magnifier effect of 50 rpm, either way, can be most pronounced) do the solution is to tune it to outside the running range, by stiffening or softening the system.

Howard

[Howard LewisParticipant @howardlewis46836]

Remember that without the use of forced induction (super or turbo charging) induction and exhaust systems can be tuned to aid “breathing” at particular speeds (The Kadenacy system) of naturally aspirated internal combustion engines. Freddy Dixon used to tune his Riley engines in this way, but kept the bonnet locked, so that no one could see what he had done.

This is what speedway racers call “Getting on the meg” with open, megaphone exhausts.

Nature, being even handed, will produce the opposite effect at half or double those speeds!

Pipe organs are tuned by making slight adjustments to the position of stops in the pipe.

A really long pipe can produce sound which is barely audible, but which can be felt in the chest, so approaching the resonant frequency of the listener’s system.

Many years ago, when young and stupid, I fitted a Ford 100E (side valve engine, so not a good breather) van with an independence type exhaust manifold and a straight through silencer, and tuned the exhaust length to resonate at peak torque speed.

With a 18 mm choke tube  and matching jets in the carburettor, it could just about match the car (With a 21 mm choke tube and jets) on acceleration from rest. But once the exhaust resonated, the car could not match the van acceleration!

Howard

[Howard Lewis]

On Howard Lewis Said:

…20Hz maybe too low a frequency for many people to hear, but can have effects (as the reports shows) and be difficult to eliminate. …

Howard

Just so, plus humans considered as sensors, have limited amplitude and frequency, some sensations overlap, and they don’t detect at the same time.   Sound is processed faster than light, but only between about 20 and 20000Hz.   Sensitivity drops with age, especially at high-frequencies; what young me heard is different from old me.   Touch can detect lower frequencies than ears, and ears are also responsible for balance, depending on fine hairs floating in a clean fluid.   Both compromised by noise damage, disease and age.

In an unnatural environment like a vehicle the brain is likely to receive conflicting information causing unpleasant symptoms.  Motion sickness and vertigo result from sensor conflicts.  As we evolved in a world were the these symptoms were caused by eating bad food, the brain reacts by ordering a purge!  We experience malaise, ratcheting up to nausea with cold sweats, then vomiting, prostration and maybe hallucinations.   Individuals vary considerably, and the brain adapts – sailors often start voyages with severe motion sickness, which subsides over time.

In Howard’s example the brain isn’t alarmed when the DMU is moving normally because vision, sound, touch and balance are broadly consistent.  But  when the DMU vibrates sub-audibly whilst stopped at stations, touch and balance detect movement, whilst sound and vision don’t.  Not enough conflict to cause seasickness, but mild malaise with no obvious cause is likely.   In the same way wind-blown caves, rooms resonated by machinery, and any other situation that confuses our senses can make us ill, usually slightly.

A problem with Psychical Research is it’s done in circumstances that wind the brain up!  Unexplained noises in a dark, cold, strange damp ruin, bit scary, in the company of like-minded individuals hoping to find weirdness. Also brains are very good at pattern recognition, but unreliable: we see castles in fires, elephants in clouds, genitals in root vegetables, and faces in burnt pancakes. People are unreliable compared with microphones and other detectors, and technology isn’t entirely trustworthy.  Reliability and repeatability have to be proven, not assumed.

Psychical Research tends to introduce observer bias and their experimental conditions cannot be recreated, leading to low-quality conclusions.   I’m not aware of any Psychical Research that’s survived scientific discipline.  Unlike natural phenomena, which do.  Another brain weirdness is humans prefer to believe in poorly evidenced low-fact notions rather than science.  I think it’s because we’re all rather lazy (I am), and understanding science is hard work.  Good to read an article stressing the need to eliminate ordinary causes before jumping to conclusions.

Music is another mystery!  Why do we like chords, but not discords?  Why does a friend love Jazz whilst I hate it?    Why do some tunes become earworms? Why did remastering Tamla Motown classics spoil them? Many say the original tracks sound better on a tinny transistor record player with iffy speakers than cleaned up and played on an acoustically sophisticated Hi-fi system with top-end speakers.    Dunno!

Dave

 

[noel shelleyParticipant @noelshelley55608]

The point about motion sickness and sailors is true ! It would take me about 3 days to find my sea legs, then a North Sea storm F10 was fine. Noel.

[Nigel Graham 2Participant @nigelgraham2]

Dave:

. In the same way wind-blown caves, rooms resonated by machinery, and any other situation that confuses our senses can make us ill, usually slightly.

I have never heard of cave draughts creating unpleasant symptoms (apart from cold!), probably because cavers know caves can be draughty, and know what is stationary and what is moving. Cave’s acoustics can be strange, though usually anechoic; and the more likely place for ULF-induced effects underground might be close to waterfalls, tumbling streams or shafts open to the surface, but again I have not heard of anyone suffering such. I might ask around!

The oddest sensation I have encountered was when with my lamp fading I turned it off while “prusiking”* up a 30-metre deep shaft. Despite being on a vertical rope I felt as if leaning sideways and moving diagonally in the complete darkness. It was so unpleasant I had to turn the lamp back on for a moment or two to clear the developing dizziness. I would guess this is related to motion-sickness. My friend waited at the top in case I needed share his lamp-light.

 

As for sea-sickness, I am a poor sailor; but it must be worse for people working inside a ship so cannot see the horizon, or the next wave-crest / trough / crest / …. May be worse still for submariners whose patrols are peacefully below the wave roots for weeks or months; then the boat surfaces for some duty reason or the last part of the voyage home.

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I take your point about the Society for Psychical Research but their paper shows they ask “What is causing the reported phenomena?”, not “What sort of ghost is this?” In this case they identified it as infra-sound from a big fan. The “ghost” is in the mind of the person who first reported it.

Quite the opposite from the infamous Borley Rectory “hauntings” explored by Harry Price in the 1930s. His writings on it suggested Price and his associates assumed ghosts; and the SPR indeed demolished most of Price’s claims.

The point is not that “psychical research” as cited does not stand up to scrutiny; but that it scrutinises others‘ “psychical” claims and debunks the supposedly-supernatural. It would seem the SPR, with whom I have no connection, is acting similarly to those who have followed the claims of Erik von Daniken or the “Bermuda Triangle” believers, and discovered them as at best seriously flawed and at worst fraudulent.

The “Loch Ness Monster” is a similar belief phenomenon, although I think there have been genuine but inconclusive attemps to determine if this lake, nearly 1000 feet deep, does hold a colony of unique life. It has also been surveyed properly, but geographically not zoologically.

 

One curious personal effect I cannot explain: I have found artificial sites like old buildings and tunnels far “creepier” than any natural ones.

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An example of the mind-set in “ghost”, alien and mystery sea-area claims is far closer to home. When BR was scrapping steam-locomotives at an indecent rate, there arose a belief in a secret Government reserve of them in military bases.

I recall one of the glossy railway magazines blew that idea down. One of its writers painstakingly examined the disposal records, and found most of the allegedly “missing” engines. By no means all were bought by Dai Woodham, and some were broken up in their home sheds. The claim had come from enthusiasts saddened by the destruction but unable to research it properly.

The writer remarked that any such imagined “reserve” is there on preserved lines; and it takes only rusty rails leading into big sheds behind high barbed-wire fences to set the imagination off!

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””””’

*Prusiking: A ratchet-action rope-climbing technique invented by Austrian mountaineer, Dr. Karl Prusik, originally for crevasse-rescue. Now used extensively in caving and industrial rope-access work.

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