Ever see an "explosion" while watching a gel test? This is why that happens.
This is a discussion on Ever see an "explosion" while watching a gel test? This is why that happens. within the Defensive Ammunition & Ballistics forums, part of the Defensive Carry Discussions category; DISCLAIMER: I am not a medical professional. I am reporting what I have seen over two years of ballistic gelatin testing. Quite a few folks ...
View Poll Results: Can sonoluminescence cause tension pneumothorax?
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Yes I think so.
No I don't think it can.
March 6th, 2015 08:44 PM
Ever see an "explosion" while watching a gel test? This is why that happens.
DISCLAIMER: I am not a medical professional. I am reporting what I have seen over two years of ballistic gelatin testing. Quite a few folks have asked why they see what looks to be an explosion when watching a ballistic gelatin test. Hopefully this post can shed some light on the subject.
The flash of light you sometimes see during a ballistic gelatin test is known as a sonoluminescent event. Sonoluminescence is the emission of short bursts of light from imploding bubbles in a liquid when excited by sound. Put simply it is a collapsing air chamber that explodes due to a violent change in pressure.
How does this occur in ballistic gelatin?
As the bullet strikes the target it creates a gap of air inside of the gelatin. We often refer to this as the temporary caivty. Before the block collapses down to its original shape, the air is low pressure and low temperature. Sometimes these air bubbles can become trapped when their escape route to the atmosphere is cut off by collapsing gelatin. In this case the collapsing gelatin compresses the air driving the pressure and temperature up almost instantly. If this occurs violently enough the air can reach temperatures in excess of 4,500K (7640F or 4226C). This causes the molecules to emit a burst of light that we sometimes are able to catch with our camera. These instances of sonoluminescence can occur in as little as 35 trillionths of a second. These events leave an expanding hot gas bubble inside of the gelatin that escapes through the permanent cavity to the atmosphere.
How does this affect humans and the firearms community?
During a few of our tests we noticed that sonoluminescence may be able to kill human beings. While testing 9mm FMJ 115gr reloads we found that the hot gas bubbles left over from sonoluminescence can sometimes become stuck in the gelatin. These stuck bubbles began to expand inside of the block causing massive 6in by 4in permanent cavities. These cavities could in theory cause tension pneumothorax.
Tension pneumothorax is a condition in which a punctured lung leaks air into the surrounding chest cavity. This air is also sucked in from the atmosphere, hence the name sucking chest wound. Over time the air keeps the lungs from fully inflating. If the condition is left untreated, the victim can begin experiencing heart difficulties and even death due to the chest pressure.
If a sonoluminescent event were to occur inside of a human, it may be possible for the trapped gasses to cause tension pneumothorax quickly. This could in theory cause the victim to die in a matter of minutes. I would love to hear from medical professionals on this topic.
What do you guys think? Could sonoluminescence help cause tension pneumothorax?
March 6th, 2015 09:23 PM
This question has been debated before (as to the cause of the flashes) but I think you're going off on entirely the wrong track when thinking this is somehow about some medical instance.
The first thing you have to understand is -- this doesn't happen in organic ballistic gelatin. This happens only in the polymer-associated synthetic "gel" such as ClearBallistics. And a human body would be a third, entirely different medium.
Whatever the final result of the reason for the flashes turns out to be, it is something that appears to be unique to the ClearBallistics (or BallistekGel or other comparable types of substances).
ClearBallistics gel is an inherently flammable medium. 10% ordnance gel is not. 10% ordnance gel is made from 90% water, and 10% pork skin. It's organic, and wet, and it never gets the "flashes" or "explosions" that show up in ClearBallistics. ClearBallistics, on the other hand, is made of materials that are inherently flammable; there are good reasons why they warn you to never let the temperature exceed 275 degrees!
Ljutic will likely respond to this thread, he's been looking into this and IINM he's of the conclusion that it is not sonoluminescence at all; I think he's come to the conclusion that it's "dieseling". Which makes a whole lot more sense to me, considering that diesel ignites solely due to pressure and not through some external spark, and the material itself is essentially a bit of "fuel", and when the flashes do happen, there's almost inevitably a darkened smear in the wound track.
If it were sonoluminescence, should we not see it happening in organic gel too? Yet we don't; you can watch Brassfetcher's super-slow-mo video, or my somewhat-slow-mo (1200 fps) vids. I've recorded repeated instances of it happening in ClearBallistics, but never have I seen it in the organic gel.
Second, you mention the bubbles that expand etc. This is, again, a property of the ClearBallistics product, and does not happen in organic gel. I've shot hundreds of blocks of each, and the ClearBallistics will sometimes have arbitrary pockets of air that really just don't have any observable reason for them to exist, but they're there. In organic gel, in the hundreds and hundreds of blocks I've shot, I've never encountered that, not once.
The fact of the matter is: ClearBallistics gel is a totally different animal. It provides reasonably comparable performance with handgun bullets as compared to organic gel, but it is not the same, and there are some things it does differently. Some of those things are a bonus (like the temperature stability). Some of those things are most definitely not a bonus (like the bounceback... that's profoundly annoying when it happens, and it doesn't happen anything like that in organic gel). And sometimes, it just does freaky wild stuff. Check this video for one of the most bizarre things I've encountered when working with the ClearBallistics product:
You'll never see anything like that with organic gel.
I like ClearBallistics for what it is, but these are some of the many reasons why I now primarily use organic gel in my testing.
March 6th, 2015 09:36 PM
Good response, STB.
I will say that, regardless of whether this particular phenomenon has an effect, I'm a bit dubious on the prevailing wisdom that temporary cavity has no effect. When the thoracic cavity is pressurized to 1000 psi and a hole the size of a Coke bottle opens up, it's hard for me to believe that everything just snaps back into place and keeps ticking like nothing happened.
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March 6th, 2015 09:50 PM
That's exactly what I was going to say.
Originally Posted by ShootingTheBull
I have a very strict gun control policy: if there's a gun around, I want to be in control of it.
March 6th, 2015 10:04 PM
Great response! I am not sure if I completely agree with everything that you're saying, but ignition of the flammable clear gel could be the cause.
Originally Posted by ShootingTheBull
You argue that it is not sonoluminescence because we do not see it happening in the organic gel, but this does not make sense. As you pointed out, clear gel and organic gel have different properties that make ammunition respond differently. Because of these different properties we could expect to see a lack of sonoluminescence occur in only one type of block.
Results in a human body could give us completely unique results. If the cause of these flashes is the ignition of flammable materials, it probably would not occur inside of a human. Because sonoluminescence does not rely on flammable materials it is possible that with enough energy it could occur in a person. But how much energy would this require? I am not trying to come up with a clear answer to this question, but I think the possibilities are interesting. Some level of energy would cause sonoluminescence inside of a person. It might be so much energy that the target explodes, but if it is not we could see some interesting results. If small arms ammunition can cause sonoluminescence we could see some serious damage to the target. It might create an expanding gas bubble. If that bubble were placed in the right area, it could in theory affect organ function. I would be interested to see if this has occurred before.
I thought of another point. What speed does your camera shoot? Sonoluminescent events occurs anywhere from 35-300 trillionths of a second. I rarely capture the flashes on film. If it were a burning of the gelatin wouldn't we see the flash last much longer?
March 6th, 2015 10:12 PM
Add enough heat and pressure (aka energy) to a material and it will burn off a proportional amount. Even if it is pure water, which will show as steam (gas) of course. That is Phys Chem 101.
The 'temporary cavity' is what causes the 'fluid shock wave' that all hunters rely on for dropping big game... or exploding prarie dogs with .223s.
This all seems like the same old physics from the '70s without any new application.
The 'sonoluminescence' is an interesting theory, but it seems difficult to reconcile sound waves into the energy required to produce visible light from the dissipation of matter. A viable event were the sonic waves much more focused & intensified. The polymeric chemical bonds seem most unlikely to yield light from the lower sonic incursion precipitated by a projectile at firearm velocities.
Matter to energy conversions require a significantly more violent chemical reaction than can reasonably be attributed to sonic waves produced well under 5000 fps with matter ~0.25 ounces.
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March 6th, 2015 10:36 PM
A pneumothorax occurs when a hole from the outside is opened into the pleural space (the space between your lungs and chest wall). Under normal conditions, your lungs "stick" to your chest wall by means of a special fluid (kind of like two wet pieces of plastic wrap- they are stuck together but slide easily). This allows your lungs to suck in air through your windpipe when your ribcage is expanded by the act of inhaling.
If you have a hole in your chest (or lungs) that is large enough (1/3 the diameter of your windpipe, IIRC), when you inhale, the air will take the path of least resistance- through the hole that's not supposed to be there, and into your thoracic cavity. As it worsens, the affected lung collapses, and the air in your chest will start pushing everything to the opposite side. This will eventually lead to death if untreated.
The one thing it does not depend on is a little explosion...
Velocity is temporary, mass is forever...
March 7th, 2015 12:35 AM
Originally Posted by maxwell97
Ever have a nurse try to start an IV in the top of your hand(mostly)?
I have a few times, and when they think they have your vein but don't, and it starts rapidly filling up with fluid. Boy does that hurt in a hurry.
Can't imagine something piecing the skin at 800-1200+ FPS and not having an impact.
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March 7th, 2015 05:04 PM
The expansion, the entrained air, the changes in pressure, temporary/permanent wound cavities -- these can have a detrimental effect on the human system.
Luminescence has no effect on anything but light-sensitive organs -- in other words, the retina.
Light can't hurt you.
(For purposes of clarity we will not include lasers in the category of "visible light.")
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March 7th, 2015 05:21 PM
Probably something similar happening in this video
March 7th, 2015 06:19 PM
I don't even understand the question. I know nothing about gels or little flashes of powder, but as far as I can tell, in order to get sonoluminescence in your thorax, you have to be shot in the thorax. A gunshot wound to the thorax in and of itself is enough to cause a hemopneumothorax, regardless of whether or not there's an explosion. All you have to do is violate the pleura to get a pneumothorax. It can be accomplished with a needle. Tension pneumos can and do develop in penetrating trauma, even though a hole in the chest is, essentially, what you do to treat a pneumothorax. This happens when some piece of tissue (or the wound edge) flops around and creates a flap (which acts like a valve) blocking the hole, so that air goes in, but has no way to escape back out again.
So, pretty much, if you're shot in the lung, you will develop a pneumothorax. Since lungs bleed, the thorax will fill with blood, too. I'm not sure what sonoluminescence would add to that, unless your question is "would the explosion cause a bigger pneumothorax to develop faster?". I suppose it would, but the question is sort of like asking "will a person bleed out faster if you rip off his arm, or if you rip of his leg?" - at the point that you're contending with that, the answer doesn't really matter all that much.
I see no reason why sonoluminescence would cause a pneumo to tension - what causes the tension is air that keeps coming in, and is unable to get out. I saw nothing in the video that convinces me that this phenomenon would poke a hole in the lung and then seal up the chest wall. I guess the thought is that the blast itself would deform the lung and blow it out of the way? Living tissue is pliable, not rigid, so after the blast (which appears to last a really short time), the blast cavity wouldn't remain and fill with air. Certainly, a bigger blast makes a bigger problem, and I'm not sure I want a 4"x6" blast to happen that close to my heart, but I don't think that a tension pneumothorax is the mechanism by which that big problem happens.
A gunshot wound resulting in a pneumothorax will likely be fatal if left untreated, but will often be survivable if the person receives prompt definitive medical care (meaning that the person actually has enough time to get to the hospital). Don't count on a pneumo as being an injury that will prevent the bad guy from shooting back at you, but if it happens to you, go to the ER - you'll need a chest tube.
ETA: I didn't vote, because my answer would be "I guess it could, but no more so than any other kind of penetrating thoracic trauma".
ETA: I'm not a trauma surgeon. I've put in more chest tubes than I can count, though.
March 7th, 2015 06:24 PM
"Life is tough but it's really tough if you are stupid"
March 7th, 2015 06:53 PM
What happened to the "Ban Game"? Different level of discussion here.
And keep it coming.
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March 7th, 2015 07:52 PM
That's why the brotha's say "I'm gon' light you up"!
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March 7th, 2015 08:51 PM
Originally Posted by usmc9688
I think that you (and Ljutic) hit the nail on the head. The paraffinic base oil used in making Clear Ballistics Gel is the most likely source of the ignition seen in these videos. The longer (enough to be capture by the cameras being used) duration of the flash suggests that the cause is not sonoluminescence, but rather the combustion of something present in the Clear Ballistics Gel.
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