How do fireworks maim?
Asked by
2davidc8 (
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)
July 5th, 2014
Around the 4th of July, we are once again hearing the annual warnings from the fire department about the dangers of handling fireworks. They say that firecrackers can blow off your fingers or even your hand (I believe them).
This got me wondering, is just a sudden, violent puff of air sufficient to take off a digit, hand, or limb? Is that just it, or is there something else that goes on? What exactly happens?
Pardon me if sound grossly ignorant on this topic. I don’t know how else to express it.
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13 Answers
It’s from stupid people using them incorrectly, and it’s not a “puff of air”, it’s an explosion, and a shockwave.
The violent chemical reaction that ensues when you ignite gunpowder can be sufficient in intensity in some fireworks to separate not only a digit or two from your hand but be bad ass enough to kill you as well.
Fireworks are explosives. Bombs, if you will.
Colourful bombs, but bombs nonetheless.
Fireworks use gun powder to burst. An M-100 is basically a quarter stick of dynamite. You don’t need much of an imagination to figure this out.
As an Audiologist, I will add the invisible injury to the hearing, which can be a physical trauma if it’s loud and close enough that the ear drum is damaged; or it can be an acoustic trauma where the inner ear is damaged.
Noise damage is permanent and cumulative. Even though one perceives their hearing as improved after a day or two, that’s just because the protective mechanism in the ear is finally relaxing, but there was some degree of permanent damage done. Tinnitus is the number one complaint among veterans at the VA, and it is a by-product of noise damage in most of those cases.
There is a difference between a puff of air from, say, blowing out a candle, and the “puff” of air generated by a firecracker. If you don’t grasp how much of a difference speed makes, compare a pencil eraser to a bullet.
Put another way, a tornado is “just a puff of wind”, and the shockwave from the explosion of a firecracker travels up to 9 km/sec. Convert that over to MPH and we are talking 6,700–20,100mph; far faster than a tornado-force wind.
The fact that the shockwave travels faster than the speed of sound leads to overpressure. That overpressure may only last for milliseconds, but slamming your hand in a car door and opening it shortly afterwards won’t hurt your hand any less than leaving the door shut; the damage was already done in that split-second where the pressure exceeded your hands resistance to being crushed.
In short, the explosion of a firecracker moves the air with at least the same force as a bullet, even without needing a physical projectile. As bullets are merely a means to transmit force, if you understand how someone could get their fingers shot off and that a sufficiently powerful explosion could make air hit as hard as a bullet, you will understand how firecrackers take off fingers.
Well…it doesn’t take a rocket scientist to figure out that handling explosives of any kind is a dangerous thing. Something explodes and shreds whatever is in it’s path of trajectory.
I was in Asia during Chinese New Year in 2010, holy crap. 2 weeks of non-stop fireworks, crazy things you could buy on the street corners, night and day of explosions all over the place.
People were allowed to set off all kinds of major explosives that would never be allowed in america.
We took our cache to a local park and set them off.
Some amazing wild items, many quite dangerous.
I gave my leftover fireworks to a french student studying in Taiwan on the Taipei metro, hope he didn’t blow himself up. lol
I can personally attest to the damage a firecracker can do. I have irrigated and cleaned a hand missing 3 fingers and part of a palm. The guy was too drunk and threw his beer instead of the firecracker. Mixing alcohol and explosives on July 4th is not a good idea.
A friend of mine gifted me an m-80 firecracker. Knowing them to be weary powerful, I lobbed it into the garden from an upstairs bedroom window. It left a size able crater. I can imagine body parts being moved from their factory locations with that kind of force.
Seems like everyone above already gave good answers. I get pretty pissed when people set off their own fireworks. It’s not worth the risk to themselves and everyone and everything around them.
Sometimes there’s a messed up fuse and there’s no way around that really. Sometimes it’s one that seems to be a dud but somehow ended up delayed and then someone gets hurt out of impatience or ignorance.
But most of the time, it’s just idiots being idiots and doing stupid shit like playing chicken with firecrackers or whatnot.
Thank you, @jerv, for a really great answer! That was what I was looking for.
And thanks to everyone else for your additional input.
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