The science of bullet flight


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RandomPerson
December 1, 2010, 08:53 PM
I used the site search tool before posting and found nothing, but I'm sure at least someone on here has talked about this...

There is a video floating around the internet of a guy shooting his pistol into a frozen lake and then discovering the bullet spinning in the ice a minute later.

Does this seem plausible? If so, what happened to the bullet? Did it fly straight out of the pistol, get stopped by the ice in place and spin? Did it fly up in the air and land face down in the ice?

I'm trying to wrap my brain around how this might happen assuming the video is real, but I have little understanding of the science behind how this could possibly happen.

Thanks for your insight.

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Imon
December 1, 2010, 08:59 PM
Well .... here's my hypothesis!

The reason why ice is slippery is because the pressure you exert onto the ice causes the top layer of ice to melt and forms a thin film of water above the ice which acts kind of like a lubricant. The same thing may be happening with the bullet.

I actually find this hard to believe too.

W.E.G.
December 1, 2010, 09:15 PM
linky http://www.youtube.com/watch?v=foZlciP6gUQ

Imon
December 1, 2010, 09:20 PM
http://www.youtube.com/watch?v=foZlciP6gUQ

Ok now that's just F!&#ing ridiculous. :scrutiny:

Gouranga
December 1, 2010, 09:26 PM
neat!

heron
December 1, 2010, 09:33 PM
Incredible . . . I'm just amazed the bullets didn't deform at all. Quite a surprise.

Live long enough, and you'll get to see all kinds of strange wonders.

Centaur 1
December 1, 2010, 10:42 PM
Considering that a .40 S&W leaves the barrel spinning at almost 50,000 rpm's, I declare this myth as plausable. :D

Zanad
December 1, 2010, 10:57 PM
Here's what I think is happening. the bullet is fired and leaves the barrel spinning. as the bullet hits the ground at a more or less specific angle, the bullet drives into the ice as it continues to spin to create a diviot so the bullet can correct itself upward and the force bounces the bullet into another "clean" spot so it can continue to spin and create a mind boggling effect.

think if a pirouette dancer.

this theory is worth exaclty what you paid for it.....

Hardtarget
December 2, 2010, 12:09 AM
I'll go with B.S.

Just me.

Mark

Tony50ae
December 2, 2010, 12:51 AM
I find it odd that at the speed the bullet hit the ice the nose does not look deformed at all. Also could be me but where are the rifling marks on the bullet?

KodiakBeer
December 2, 2010, 01:29 AM
Somehow, I think not...

ShaiVong
December 2, 2010, 01:40 AM
On the first one they focus on you can see a line running off to the right of the bullet. It looks like it hit the ice, bounced out, and skipped like a top a little ways along the ice.

Seems kind of like a bad idea.

o Unforgiven o
December 2, 2010, 01:51 AM
Gonna have to call this one BS...

General Geoff
December 2, 2010, 02:00 AM
It's real. Dangerous to demonstrate (due to chance of ricochet), but real.


Think about how many bullets you can find in a dirt berm that are completely undeformed. Ice isn't exactly steel or concrete. And yes, the bullet is spinning really fast coming out of the barrel. So if you stop the bullet's forward motion while allowing it to maintain its spin (via hitting a relatively slippery but solid surface such as ice), it's perfectly plausible that a bullet could be found spinning on the ice like that.

And furthermore, if you shoot at the ice at an angle nearly perpendicular to the ground, the gyroscopic effect of the spinning will maintain the bullet's upright (base-up, nose-down) orientation, hence finding it spinning in place like a top.

KodiakBeer
December 2, 2010, 02:17 AM
Or... you could just spin a slug from a string (like a Dreidel) while another guy shoots, and then pretend the spinning slug came out of the gun.

rondog
December 2, 2010, 04:08 AM
Or fake the whole thing with a computer and skillz.

BeerSleeper
December 2, 2010, 05:15 AM
Shouldn't a common .40 round penetrate the ice about 6 inches or so?

General Geoff
December 2, 2010, 11:08 AM
Or... you could just spin a slug from a string (like a Dreidel) while another guy shoots, and then pretend the spinning slug came out of the gun.

Good luck getting a .40 caliber slug to spin that fast for that long with a string.

DuncanSA
December 2, 2010, 11:25 AM
Conservation of angular momentum in a very low friction environment? Maybe someone with a scientific/physics background could comment.

General Geoff
December 2, 2010, 11:34 AM
Gyroscope in a microgravity environment (http://www.youtube.com/watch?v=I3S-c_s_syY)

glock36
December 2, 2010, 11:35 AM
I shot at a block of ice that came from frozen water bucket with a P226 .45 cal. The block crumbled when hit, I found the slug in the pile of ice chipps and it was not deformed one little bit. I think what the video shows is quite possibel.

kragluver
December 2, 2010, 11:50 AM
A while back, a poster that stated he was a crime scene investigator stated that they regularly used blocks of ice to shoot bullets into so that the bullets would not be deformed. He stated that they had been doing this for some years and it worked very well - so far as not deforming the bullets. I think the video is certainly plausible. Once the ice stops the bullet, it won't necessarily stop the spin - which is very high speed as stated above. Friction coefficient on ice is low enough and after the bullet has come to a stop, it will act like a spinning top. The motion seems reasonable.

ShaiVong
December 2, 2010, 12:47 PM
If you watch the video with the sound up, while he's watching the first bullet slow down it begins to tip over and you can hear the rifling grooves humming on the ice, which slows it down faster and stops it.

S. Hill
December 2, 2010, 03:55 PM
I think that Gen. Jeff ;) has it right. I think it is real, and that the bullet they fired is spinning on top of the ice. I also think that it is CRAZY STUPID to do what they are showing in the video. Not sure about the energy of the ricochet coming back to bite you…. But I certainly don’t want to be hit with one!

You are able hear the high RPM of the bullet as it sits in the little ice pocket. That thing is spinning at a very high speed. There it sits, spinning away….

I think that shooting a bucket of ice isn’t the same as shooting into a HUGE block of ice (like the surface of a lake). There is a lot more support with the lake ice that doesn’t allow it to shatter and let the bullet pass. It bounces out, and occasionally lands on top of the ice near where the shooter is standing. AGAIN, stupid, but plausible. There it sits, spinning at (what did you figure….) 50,000 RPM? I don’t know how else you would get it to “sing” like that.

therewolf
December 2, 2010, 04:01 PM
I'm just impressed they didn't" put their eye out" with their

pistol while making the video...:D

S. Hill
December 2, 2010, 04:05 PM
I'm just impressed they didn't" put their eye out" with their

pistol while making the video...:D
LOL That's funny! My mommy always warned me!!!

rcmodel
December 2, 2010, 04:10 PM
More YouTube BS!!!
I've noticed a very high incidence / percentage of Morons on YouTube where it comes to all things gun related.

Shoot a frozen lake, and the bullet will expend all it's energy knocking a big divot out of the surface of the ice. If it doesn't knock out the divot, and then bounce right back and hit you.

There is no possible way any bullet could still be spinning 59.99999999999 seconds after it expended all of it's energy on the ice.

Even a 50 pound artillery shell wouldn't carry enough rotational energy do that.

rc

Snowdog
December 2, 2010, 04:19 PM
I'd say this is MythBuster worthy. I've seen very strange things that I classify as "shouldn't be possible" while plinking on informal ranges. Though I hold some skepticism with all strange things I find on YouTube, I wouldn't be surprised at all if these spinning bullets the real deal.

General Geoff
December 2, 2010, 04:23 PM
There is no possible way any bullet could still be spinning 59.99999999999 seconds after it expended all of it's energy on the ice.

You sound very sure of yourself. Do you have any reason (other than a hunch) to say that there is "no possible way"?

Rotational energy is expended very slowly on a slick surface such as ice. A gyroscope could easily spin for over a minute on ice, I don't see why a bullet could not.

ShaiVong
December 2, 2010, 04:26 PM
You sound very sure of yourself. Do you have any reason (other than a hunch) to say that there is "no possible way"?

Rotational energy is expended very slowly on a slick surface such as ice. A gyroscope could easily spin for over a minute on ice, I don't see why a bullet could not.
This. Incredulity, like credulity, needs to be founded... not a 'I find that hard to believe, ergo it's impossible'.

rozziboy18
December 2, 2010, 04:37 PM
totaly do able. i have shot at iced over lake last winter in the 21 day freeze we had in tn. never thought to look for bullets spining on ice, but did find the some distance away undamaged. i might have to test this one this winter at the range. :)

S. Hill
December 2, 2010, 04:50 PM
More YouTube BS!!!
I've noticed a very high incidence / percentage of Morons on YouTube where it comes to all things gun related.

Shoot a frozen lake, and the bullet will expend all it's energy knocking a big divot out of the surface of the ice. If it doesn't knock out the divot, and then bounce right back and hit you.

There is no possible way any bullet could still be spinning 59.99999999999 seconds after it expended all of it's energy on the ice.

Even a 50 pound artillery shell wouldn't carry enough rotational energy do that.

rc
As much as I appreciate your view on things, how else do you think they got the bullet to spin that fast for that long?

rcmodel
December 2, 2010, 05:27 PM
Maybe the same way they got a swarm of bees to pick up a lap-top computer on YouTube.
Tricks & Shenanigans for lasting YouTube fame.

If it stayed in one place spinning on ice, the rifling marks on the bullet would melt the ice and turn it to water.
If there was water present, you would have friction against the rifling marks on the bullet.

It in turn would either stop spinning very shortly due to the water friction.
Or propel itself to some place you couldn't find it, like a little paddle wheel boat!

rc

General Geoff
December 2, 2010, 05:32 PM
So your reason for saying the video is a hoax, is that it could be a hoax.

Given only the footage linked, your conclusion is unfalsifiable and thus not scientifically sound.


If it stayed in one place spinning on ice, the rifling marks on the bullet would melt the ice and turn it to water.
Yes, the reason ice is slippery is that things contacting it tend to create enough friction to form a thin film of water between the object and the ice itself. If the environment is cold enough that this film does not form (i.e. antarctica in winter), you will find that ice is in fact not slippery at all.

If there was water present, you would have friction against the rifling marks on the bullet.
There is some friction there.

It in turn would either stop spinning very shortly due to the water friction.
Where are the numbers to back up your assertion?

Or propel itself to some place you couldn't find it, like a little paddle wheel boat!
The bullets are found in small divots they have formed in the ice; the rifling marks can't make the bullet "climb" out of the divot any more than a spinning top can climb out of a bowl.

S. Hill
December 2, 2010, 05:54 PM
The way I saw it, it is spinning on the round nose, not on the side where it would be engraved by the rifling. There would be very little disruption or drag, if the nose of the bullet were not deformed when hitting the ice.

Snowdog
December 2, 2010, 06:36 PM
In two of the YouTube videos I've seen involving spinning bullets on ice, the rounds were fired from Glocks. Recovered bullets fired from polygonal rifling lack the telltale lands etching found on bullets fired from barrels with traditional rifling, leaving the jackets relatively smooth in comparison.

I'm keeping an open mind on this issue since I became aware many years ago that I lack the omniscience that I deserve.

ShaiVong
December 2, 2010, 06:42 PM
In two of the YouTube videos I've seen involving spinning bullets on ice, the rounds were fired from Glocks. Recovered bullets fired from polygonal rifling lack the telltale lands etching found on bullets fired from barrels with traditional rifling, leaving the jackets relatively smooth in comparison.

I'm keeping an open mind on this issue since I became aware many years ago that I lack the omniscience that I deserve.
Well my Glock has a dial on the side where I can adjust the muzzle velocity. You can just have it drop out onto the ice and spin like a top. It's the new Mass Effect Glock. Didn't you know they can do anything?

Snowdog
December 2, 2010, 06:54 PM
Well my Glock has a dial on the side where I can adjust the muzzle velocity. You can just have it drop out onto the ice and spin like a top. It's the new Mass Effect Glock. Didn't you know they can do anything?

Um, yeah... not sure where you're going with all that.

rondog
December 2, 2010, 07:20 PM
Many years ago I watched a friend of mine fire a .44 magnum straight down into a frozen lake, right at his feet. The bullet made a pretty big divot, but just bounced right back out and landed on the ice. I don't remember how deformed it was, or even what kind of bullet, just that it was a .44 mag Super Blackhawk. We were surprised, because we figured it would just blow a big ol' honkin' hole right through the ice.

Jed Carter
December 2, 2010, 07:39 PM
I would vote pure BS, but then again 1000 fps, 1 in 6" twist = 2000 revolutions per second X 60 =120,000 RPM! With virtually no friction, theoretically possible but bullet is too balanced and pristine...BS. Fun seeing fools with firearms on U-tube though.

W.E.G.
December 2, 2010, 08:07 PM
Well my Glock has a dial on the side where I can adjust the muzzle velocity. You can just have it drop out onto the ice and spin like a top. It's the new Mass Effect Glock. Didn't you know they can do anything?

I have the enhanced version.

I can even set mine to dum-dum.

Oyeboten
December 2, 2010, 10:01 PM
This was well known with Artillery Shells in both World Wars, when fired up at a steep angle...they'd come down oddly sometimes, rear end first, and, just lay there spinning a while.

ShaiVong
December 2, 2010, 10:10 PM
Now that's something I wouldn't want to get close enough to film.

TriTone
December 9, 2010, 11:20 PM
Maybe the same way they got a swarm of bees to pick up a lap-top computer on YouTube.
Tricks & Shenanigans for lasting YouTube fame.

If it stayed in one place spinning on ice, the rifling marks on the bullet would melt the ice and turn it to water.
If there was water present, you would have friction against the rifling marks on the bullet.

It in turn would either stop spinning very shortly due to the water friction.
Or propel itself to some place you couldn't find it, like a little paddle wheel boat!

rc


No offense intended rcmodel, but you need to revisit your high school physics books.
Also, it should be said that the science behind "slipperiness is still, in fact, under investigation by modern science, believe it or not!
However, based on generally accepted physics, an explanation would be this.

There are two types of physics working here. Our macro physics that the world we perceive around us with our human senses observes and the sub-molecular physics that are still being worked out.
Remember that we are seeing the world on a macro scale. We have a couple things from this perspective. 1) The bullet is ending up in a different location on the ice than it was fired at. (ricochet)
2) The bullet is still in motion long after we have fired it. (we dont get to observe this normally)

So, yeah. It seems strange and unwieldy. This problem involves entries from Molecular dynamics of cryogenic particle bodies/water clusters and thermodynamics, quantum physics, macro physics, etc. So I am disclaiming that I am not an expert in any one of these particular areas but have done work in all of them.

When a bullet is fired into ice, because of the weak molecular lattice work in ice (weak type hydrogen based) bonds (which lend to the fact that ice has a lower density that water, hence the function of ice floating in water) break down very quickly. The water formed at the very point of the first molecular of the tip of the bullet hitting the first ice bond/ice molecule then spreads through molecular adhesion over the side of the bullet. ( think of the blood from a shaving cut spreads quickly through a small piece of tissue when the very tip hits the globule of blood.) This forms a thin film of water around the projectile. This film of water allowed the (still pushing forward bullet) to continue spinning. Of course it is reducing in rpm but very slowly as it is lubricated. As the bullet made its initial impact at what looked in the video to be about a 45-120 degree angle from the shooter into the ice, the molecular lattice work of hydrogen bonds snapped and bent at the impact area to absorb most of the forward energy. The ice is not dense enough, plus the property of the weak bonds keep the water turned into ice breaking down so quickly, that the bullet does not get disformed. It is far too dense and solid. Pure water has a better chance of deforming a bullet than ice, and even water can not disform a bullet. It may seem strange, because to use we perceive ice as being very hard compared to water, but on the molecular level, water is more dense, than ice.



The flat, solid face of the bullet assisted in the rebound projectory. I believe if they had been round nosed the rebound projectory would have been more chaotic and it would have been more likely the shooter or bystanders might have been hit. Not sure on this though.

The bullet then essentially rebounded across the ice through the light snow covering until the snowy covering absorbed enough of the remaining energy through the breakdown of ice latticework from energy transfer that the bullet could no longer continue moving away from it's impact point. Depending on the way it bounced and slid off, it either slid on its nose or off-canter. If it slid on its nose it would continue spinning until it dispersed enough energy, similar to spinning a quarter. Imagine spinning a marble with an oil coating. It's also possible but less likely the bullet dumped all of its forward momentum into the inertia of the ice on impact and moved away from impact point only through the merits of its rotational velocity.

Further, scientific testing would be required to determine for sure. But there is some very plausible scientific explanation.

Also, the comment that it would stop spinning very shortly because of water friction is scientifically ignorant. Again, not insulting you rc, stating fact. While you may have a good basis for a conjecture with the icea of it losing energy through action of the jacket molecules against the water molecules, transferring that friction energy away as heat. You're insertion of an arbitrary time measurement is completely unsound and unscientific, and therefore removes the bearing of your conjecture towards the subject at hand.

What bothers me in this thread is not the posts like, "looks like bs to me". Yah, it did to me at first, but that doesn't mean it is. Still, you can post what you want, nothing wrong with that. I've made posts like that on places too! lol. It's also completely cool for people to work together and try and figure something out with possible explanations. Where it crosses the line and starts degrading everything is when people post short statements of what they think with strong disqualifiers.

Don't be ignorant. Post humor, post conjecture, post fun, post disbelief, but dont post fake science and hammer out a ruling with it, it doesn't lend your posts credibility and it makes it sound like you're just trying to sounds smart or make people think you're more knowledgeable in a particular area than you actually are.

if you insist on it, at least post some disclaimers so you don't come across as being a know it all or something :).


So theres my contribution, feel free to tear at it, but please base your claims with established science.

-Tri

TriTone
December 9, 2010, 11:38 PM
*Double Post*

John Wayne
December 10, 2010, 01:06 AM
That's awesome! Very cool indeed that that is possible, but I hate to ask how the first genius found that out.

Freedom_fighter_in_IL
December 10, 2010, 01:37 AM
TriTone, You passed up High School Physics and went straight into Physics 3 (I hated Physics 3 btw) But your assessment seems plausible. Thought you were going to start quoting String Theory followed up by Chaos Theory for a minute there! Both of which could apply as well :)

Basically this is just a couple of jackasses with a firearm making gun owners look retarded. "It's always fun and games till someone loses an eye!" My mommie used to say that too!

Old krow
December 10, 2010, 08:44 PM
slipperiness is still, in fact, under investigation by modern science, believe it or not

but please base your claims with established science


Established science under investigation? :scrutiny: :D

ught you were going to start quoting String Theory followed up by Chaos Theory for a minute there! Both of which could apply as well


That's hunting chipmunks with a .50 BMG. :rolleyes: :D

mickeygrimreaperblueeyes
December 10, 2010, 09:00 PM
P.T. Barnum stated that there's a sucker born every minute.

I'm a sucker for this youtube post.

I noticed the sound made from the bullets spinning in the ice by the grooves formed on
the copper jacket. I agree that this youtube post is in fact real.

The laws of physics state that collision and impact don't necessarily effect the rotation of an object. This is entirely plausible.

I for all intents and purposes, have considered things that will blow a CSI researcher's mind and finding near perfect bullets in a bullet trap and reloading them is one thought I've had. Multiple and different multiple barrel riflings would definately inflect some doubt into the CSI person's mind. What about using a barrel with opposite twists for the next time? HUMM???

Now that I know how to collect the perfect re-usable bullet, I guess I will keep a magazine of these multiple used bullets reloaded for home protection. Seeing as I will only be shooting released convicts that have the intent to kill me and rape my wife, because I'm a rule enforcing corrections officer, the CSI person should have a good time differentiating the riflings...

TriTone
December 10, 2010, 09:44 PM
Established science under investigation? :scrutiny: :D



That's hunting chipmunks with a .50 BMG. :rolleyes: :D
Yup!
http://www.nytimes.com/2006/02/21/science/21ice.html
Established science used to be that the earth was flat too!

If we don't continually challenge our "established science" we never make any great discoveries!



I agree about the irresponsibility of these guys. Also how the one guys is like " I don't even care if i get hit ". Yeah...what do you wanna bet he's not been hit before and he must be pretty dumb if he thinks its not a big deal lol. I've been hit before and I know I never want that to happen again.

Old krow
December 10, 2010, 10:06 PM
If we don't continually challenge our "established science" we never make any great discoveries!

I got that part. :) Sorry, I just saw a little irony in all that. It's probably possible, but after all this, all I can say is, thank God for frictionless physics!

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