Showing posts with label lab. Show all posts
Showing posts with label lab. Show all posts

Tuesday, October 30, 2012

The Tale of the Haunted Laboratory


The Tale of the Haunted Laboratory 
An infrasound ghost story 

A retelling (with some creative license) of the “Ghost in the Machine
Published in the Journal of the Society for Psychical Research, Vol. 62, No 851 April 1998 by Vic Tandy and Tony R Lawrence of Coventry University.

Not too long ago, in a lab not too far away there was a haunting. This lab was a spacious playground for engineers, and housed many odd contraptions. But this isn’t a story about what work went on in the lab, this is a story about the haunting of this lab.

One morning an engineer arrived early to find a distressed cleaner. When he talked to the cleaner she admitted that she was shaken up due to having felt a presence in the lab. Not only that, she claimed to have seen something. Our engineer does not believe in ghost or supernatural things and just shrugged the incident off.

However, soon he, too, was noticing things. He sensed an odd dark mood in the room, almost depressing. Occasionally he had a cold shiver, or a feeling that someone was standing right beside him, but the closest person was across the room. These observations were made by all three regular inhabitants of this lab.

A feeling of unease and discomfort about this particular lab began to grow, and then to spread. However the workers were very busy people and tried their best to ignore it.

One night,

our engineer was working late

… alone.

Even though he was sweating he began to feel cold, he felt depressed, groans and creaks from the empty factory that housed the lab only added to his growing discomfort. But there was also something else. He kept feeling that there was someone in the room, but that was impossible. There was no way for anyone to enter or exit the lab without walking past his desk.

And yet…the feeling was there.

This being a lab, there were all sorts of gasses and chemicals around that if inhaled could cause all sorts of problems. He began to check everything in lab to make sure nothing was leaking. Everything was fine, everything looked normal. Annoyed with himself he went and got a cup of coffee, tried to laugh it off and went back to work.

And then

It happened

He began to feel like he was being watched…

AND THEN HE SAW SOMETHING!

To his left a figure emerged! It was faint and on the periphery of his vision but it moved, and it moved JUST LIKE A PERSON! It was gray and made no sound but there it was, moving towards him. The hairs on his neck were standing straight up, and he was terrified! Slowly, he worked up the courage to face this apparition. As he slowly turned his head the figure vanished, leaving no evidence of its existence.

Badly shaken from this experience, he quickly called it a night and went home.

Now our story could end there with the mysterious ghost apparition in the lab, appearing late at night when you are working alone, and vanishing when you look at it. But that is not the end of our story, no, for he IS an engineer and the very next day he was back in the lab.

Now he was entering a fencing competition and had some work to do on his blade. He didn’t have to do this in the lab, but decided there was plenty of room and all the tools he needed, so he decided to bring his supplies into the lab to do this work. He placed the blade in a vise on a table in the middle of the lab and left it to go look for something else he needed in order to finish this work.

Again

… something ...

happened

When he returned, the free end of the blade was violently vibrating! Given the events of the previous night he was understandably terrified! However, this being daylight hours and being an engineer, he took a deep breath and composed himself and curiosity took over. What was making the blade move? The blade had to be receiving energy from somewhere in order for it to move in such a manner! This energy had to have a varying intensity at a rate that was precisely that of the resonant frequency of the blade. This type of energy is known as sound. He took stock of the sounds he could hear in the room. A lab can be a very noisy place, but an engineer also knows that there is sound we can’t hear, frequencies too low for humans to resolve. He starts to experiment with the hypothesis that what is causing his blade to move is this low frequency sound known as infrasound. 

He moved the blade around the room noticing the amplitude of the vibrations and found that in the center of the lab it was the largest, and that the vibrations in the blade stopped all together at the far end of the lab. Curious! Then it hit him! A low frequency standing wave! He did some quick calculations to see what frequency this wave would be given the size of the lab (see actual paper). This quick calculation resulted in a wave of approximately 18.89 Hz or 18.89 cycles per second which is below the lower end of human hearing at 20 Hz.

“So…” he thought “we are sharing the lab with a 19Hz wave. But where is it coming from and what do these sorts of waves do to people?”

Our engineer quickly found the source of this wave. A quick round of questions revealed that a new fan had recently been installed at one end of the lab. When this was switched off the vibrations in his blade vanished. That problem solved he began to research what sort of effects these waves have on humans.  This involved a bit of research.

There was a report of workers in a factory reporting that a specific bay made them feel uneasy. This was explained by a higher level of low frequency sound in that area of the factory due to a fan in the AC system. There was also a report of a group of workers at a university who all reported the same uneasy feeling and dizziness when a specific fan was turned on. These cases were explained by low frequency sound in the 15-20Hz range.

But what about the apparition that appeared? Further research produced a resonance frequency of the human eyeball in a NASA report! 18Hz causes the eyeball to vibrate and created a smearing of vision.

He had identified his ghost. It was a standing wave caused by a new fan in the lab.

Now for the exorcism! A modification was made to the mounting of the fan and the standing wave, ghost, uneasy feeling, and chills vanished from the lab!

So next time you think you see a ghost, remember it might just be infrasound!

(This story was a retelling of the excellent paper written by our hero Vic Tandy and Tony R Lawrence about an experience that V. Tandy had while working in the lab mentioned in this story.  Their paper “Ghost in the Machine” is an excellent read, and one of my favorite infrasound stories. I decided it could use a Halloween spin! I hope you enjoyed this little ghost story!) 

Friday, August 17, 2012

ALOHA video Fridays: Surf infrasound part 9

Aloha! This is the 9th video in a series of 9 on surf infrasound. 
Enjoy, and have an excellent weekend!Dr. Milton Garces presents the conclusions derived from the series of surf infrasound experiments.

Closing credits for the surf infrasound documentary. Grinding surfing footage from one of the smaller days of our experiment in Kauai.

Friday, August 10, 2012

ALOHA video Fridays: Surf infrasound part 8

Aloha! This is the 8th video in a series of 9 on surf infrasound. 
Enjoy, and have an excellent weekend!Dr. Milton Garces describes the surf infrasound deployment at Temae Beach, Moorea, French Polynesia.

Friday, August 3, 2012

ALOHA video Fridays: Surf infrasound part 7

Aloha! This is the 7th video in a series of 9 on surf infrasound. 
Enjoy, and have an excellent weekend!Dr. Milton Garces describes the surf infrasound deployment at Polihale Beach, Kauai. We captured the infrasound from a massive swell, with 40ft peeling waves!

Friday, July 27, 2012

ALOHA video Fridays: Surf infrasound part 6

Aloha! This is the 6th video in a series of 9 on surf infrasound. 
Enjoy, and have an excellent weekend!Dr. Milton Garces describes a surf infrasound experiment at Makalawena Beach, Hawaii.

Friday, July 20, 2012

ALOHA video Fridays: Surf infrasound part 5


Aloha! This is the 5th video in a series of 9 on surf infrasound.
Enjoy, and have an excellent weekend!

Dr. Milton Garces explains the sonification of infrasound. The surf sounds on this clip get deeper, crossing over to the inaudible.

Friday, July 13, 2012

ALOHA video Fridays: Surf infrasound part 4

Aloha! This is the fourth video in a series of 9 on surf infrasound. 
Enjoy, and have an excellent weekend! Dr. Milton Garces describes some of the advantages of using infrasound arrays.

Friday, July 6, 2012

ALOHA video Fridays: Surf infrasound part 3

Aloha! This is the third video in a series of 9 on surf infrasound. 
 Enjoy, and have an excellent weekend!
  Dr. Milton Garces outlines possible source processes for surf infrasound.

Friday, June 29, 2012

ALOHA video Fridays: Surf infrasound part 2

Aloha! This is the second video in a series of 9 on surf infrasound. 
Enjoy, and have an excellent weekend!

Dr. Milton Garces discusses the infrasonic signature of individual breaking ocean waves.

Friday, June 22, 2012

ALOHA video Fridays: Surf infrasound part 1

Aloha! This is the first video in a series of 9 on surf infrasound.
Enjoy, and have an excellent weekend!
 
Welcome to the world of infrasound! Volcanoes, severe weather, tsunamis, meteors, earthquakes, and all large things that blow up can produce inaudible atmospheric sound, which can be recorded by a global microphone network. In this clip, Dr. Milton Garces introduces low-frequency acoustics as background to surf infrasound studies.

Friday, June 15, 2012

ALOHA video Friday - Song of Pele

Here is a video clip from the lab vaults. This one is from the PBS show Kilauea: Mountain of Fire that aired on PBS Sunday, May 2, 2010

Pele, the Hawaiian volcano goddess, sings a continuous chorus beneath the surface of the Earth. Geophysicist Milton Garces uses infrasonic technology to listen in on whats happening in Kilauea's lava tubes. 

Enjoy!

Wednesday, June 6, 2012

What is infrasound?

(Note, this will also be posted under the "What is infrasound?" tab for the blog for quick and easy reference!)


What is infrasound? An ongoing, never ending, quest to explain what we do…. 
"In the grand scheme of things we're all pretty much blind and deaf" by Abstruse Goose

This comic from Abstruse Goose is a good place to start. Take a second to acclimate yourself to the ranges of light and sound that we cannot perceive. That low end of sound is the area we are going to explore.
Infrasound is technically any “sound” below 20Hz. I don’t blame you if that makes zero sense. So let’s start with what sound is. Sound is an oscillation of pressure. Our ears detect these vibrations and our brains translate these signals into what we hear. Sound is a wave.

There are several different parameters we use to describe waves. The most important (for reading this blog) is frequency. Frequency can also be seen as the x axis on the above figure, using the unit Hz. Hertz (Hz) is cycles per second. The following figure will help illustrate how waves of similar amplitude look when they differ in frequency. 

There are several sine waves in the above diagram with one thing different about them. Let’s say that these waves are all 1 second long. That means the X axis is time and the Y is amplitude. We can now talk about my favorite word: frequency. Let’s start with the red line. Focus on the blue dots at the trough or lowest point of the wave. Every time the wave returns to that trough, it goes through one cycle. If we count those troughs we can see that it goes through its oscillation 4 times. That is 4 cycles per our defined time scale and since our time scale is one second that is 4 cycles per second. So the red line is 4Hz. The orange, green, blue, and purple have more cycles in our defined time scale and therefore they have a higher frequency. Let’s skip down to the purple line and look at the frequency in Hz again. Let’s look at the blue dots in the troughs again. There are 15 troughs in this wave, plus about half a cycle left over, so 15.5Hz.  

Now just for fun imagine if our time scale was 2 seconds instead of 1, then the red line would be 2Hz and the purple line would be 7.75Hz.

Hopefully that made some semblance of sense, because now we are going to use that to explore sound and infrasound. Frequency and amplitude are two of the main variables that we use to describe a signal. We are again going to start with the audible range.

The human ear can, in general, hear from 20Hz to 20,000Hz. Above 20,000Hz is ultrasound (bats use it and dogs can hear it). Below 20Hz is infrasound (whales, giraffes, and elephants use it to communicate).  


Now, to put some of these numbers in context, let’s move to the piano. In the middle of the keyboard is the “middle C”, which is blue in the above figure. This musical note has a frequency of 261.626 Hz. In that range is also the “A” (in yellow), that you always hear when an orchestra tunes before a concert. This note is at 440Hz.  The lowest note on the piano is 27.5 Hz and the highest is 4186.01 Hz. Now for some fun, here are some links so you can hear the different pitches.



First is concert A (440Hz)
In the Baroque period an A was 415 Hz
If we jump down an octave (440/2 = 220) this is what it sounds like 
… and if we go down another octave (110 Hz) this is what it sounds like 

In the sound range, we perceive amplitude as “loudness.” In Infrasound we use Pascals (Pa) or a measure of pressure to quantify amplitude of a signal.

Ok, enough of audible sound. That is not what this blog is about, it is about INFRASOUND!

Infrasound, like I said, is anything below 20Hz (the value for the base of human hearing). There are a few more variables I would like to define before we go any farther. The speed of sound in air is one of them. In general the work in this blog is done on signals that travel through the atmosphere. Because the temperature and density of the atmosphere affect the speed of sound, we are going to just use the speed of sound at sea level throughout this blog. That value is ~340 m/sec or ~1116 ft/sec. You will generally see us using the metric units.

Now that we have the speed and frequency of a wave, we can talk about how long it takes to pass a single point, and how long the wavelength is. Let’s go back to our sine wave shall we?


The wavelength is a measure of length. In order to calculate the wavelength for a wave you need the velocity, the frequency, and this equation:   where  is velocity, is wavelength, and  is frequency. 

Let’s plug in some numbers! Let’s take our 4Hz signal from before and 340 (m/s). If we rearrange the above equation to velocity/frequency = wavelength we get 340(m/s) /4 (/sec) =  85 meters.  The length of a sound wave that is 4Hz is 85 m. We have the velocity so we know that each second 4 waves can pass by a single point.

Alright, now that we have all of that out of the way….

Infrasound is any sound below 20Hz. That makes more sense now right? Good.

Now let’s go hunt some signals! 

Tuesday, January 17, 2012

Getting out of the lab!

Have you heard about the HVO open house!?

Well, we have! Several of the iSoundHunter team are headed to Volcano this weekend for the open house, and some hiking. Let us know if you are going to be there as well!

Wednesday, December 14, 2011

Wednesday Geology Photos

Today I have some older lab field work photos for you! These photos are from Palau. 
This is where Palau is.

The first few photos are of the islands, taken on the way back from a diving trip. The last few are some shots of the reef. Enjoy! Also there are a ton more on the facebook page.





Remember there are a ton more on the facebook page!

Tuesday, December 13, 2011

Gettin' the lab involved... Tuesday Geology Photos

One of my coworkers at the lab had some pretty sweet shots of erosion in the dry valleys of Antarctica on his computer from his thesis field work. They were too awesome to not share!



And this last one is a hanging valley in New Zealand! 
Hope you enjoyed those photos! More tomorrow!

Friday, November 25, 2011

Some good advice

My husband passed on this pearl of wisdom from an old Chem prof he worked for one summer...

"Whenever you start at a new lab offer to clean! Chances are it needs it and then you will know where everything is."
Are real labs ever this clean!? Random internet photo

I took that to heart and over the last few weeks the lab is looking better and now I can find things! Now I am moving onto the digital files. Everyone has their own copies of the forms we use on their own computers but we don't have blank copies kept in one central location. Time to fix that!

Also I am going to teach myself LaTex and make some templates. (see positive thinking! I bet whats going to happen is I get frustrated and have to call friends for help! )