Spinning bullets on a frozen lake...

SteamWake · 10-25-10, 09:06 AM

Okay you physics professors splain this one !

http://www.break.com/index/spinning-...n-lake-1936597

(Video of bullets being shot into a frozen lake and the slug ends up spinning like a top).

AngusJS · 10-25-10, 09:32 AM

The bullet is showing the same spin that it would have while in the air (i.e. along the same axis). I guess it bounced off the ice, landed again, and then maybe its heat melted the ice around it, which provided lubrication that let it spin for so long? I'm not a physics prof, though.

I'm just amazed that those guys weren't hit by ricochets - that bullet ended up behind them, just off to the left, after all.

SteamWake · 10-25-10, 09:43 AM

Ever seen that video of a guy firing a 50 cal into a piece of metal, the slug comes rocketing back and nearly takes the guys ear off

Dowly · 10-25-10, 09:48 AM

Quote:

Originally Posted by SteamWake

Ever seen that video of a guy firing a 50 cal into a piece of metal, the slug comes rocketing back and nearly takes the guys ear off

Schroeder · 10-25-10, 10:01 AM

The barrels of guns are designed to force bullets into a spin when they are fired through them. This stabilizes the bullet in flight and makes the weapon more accurate.http://en.wikipedia.org/wiki/Rifling

Jimbuna · 10-25-10, 10:25 AM

Add the fact that there will be next to no friction/resistance to the spinning attitude of the bullet because the ground is actually ice.

Penguin · 10-25-10, 10:46 AM

I also cannot explain it, so far I regard Angus' explaination as the most reasonable one. Some observations:
- The bullet spin is definitely clockwise. Can any of you gun nuts identify the firearm and confirm that the barrell of this model provides a clockwise spin?
- Each shot makes an impact onto the ice, however the bullet most likely bounces back when it is fired in a certain angle. This angle should be rather flat < 45°, otherwise the projectile would penetrate into the ice.
- I guess the little wall of frozen ice and snow, where the targets are located, has something to do with it. The bullet gets reflected back towards the shoote/camera guy. So there must at least 2 reflections.
- The colder the ice gets, the harder it is. I read somewhere, when the temperature reach -25° C, the hardness of ice would be the same as steel. There are no deformations visible, as I would have expected when a projectile gets reflected by a hard surface. So either it was not that cold, or the energy of the bullet melted the ice on the impact point enough to provide a "smooth" bouncing.

Another good argument for free firearms for all, so we can all recreate this little experiment in the winter!

10-25-10, 09:06 AM	#1
SteamWake Rear Admiral Join Date: Mar 2005 Posts: 13,224 Downloads: 5 Uploads: 0	Spinning bullets on a frozen lake... Okay you physics professors splain this one ! http://www.break.com/index/spinning-...n-lake-1936597 (Video of bullets being shot into a frozen lake and the slug ends up spinning like a top). __________________ Follow the progress of Mr. Mulligan : http://www.subsim.com/radioroom/showthread.php?t=147648

10-25-10, 09:43 AM	#3
SteamWake Rear Admiral Join Date: Mar 2005 Posts: 13,224 Downloads: 5 Uploads: 0	Ever seen that video of a guy firing a 50 cal into a piece of metal, the slug comes rocketing back and nearly takes the guys ear off __________________ Follow the progress of Mr. Mulligan : http://www.subsim.com/radioroom/showthread.php?t=147648

10-25-10, 10:01 AM	#5
Schroeder Navy Seal Join Date: Apr 2008 Location: Banana Republic of Germany Posts: 6,170 Downloads: 62 Uploads: 0	The barrels of guns are designed to force bullets into a spin when they are fired through them. This stabilizes the bullet in flight and makes the weapon more accurate.http://en.wikipedia.org/wiki/Rifling __________________ Putting Germ back into Germany.

10-25-10, 10:25 AM	#6
Jimbuna Chief of the Boat Join Date: Feb 2006 Location: 250 metres below the surface Posts: 190,473 Downloads: 63 Uploads: 13	Add the fact that there will be next to no friction/resistance to the spinning attitude of the bullet because the ground is actually ice. __________________ Wise men speak because they have something to say; Fools because they have to say something. Oh my God, not again!!

10-25-10, 09:32 AM	#2
AngusJS Seasoned Skipper Join Date: Jan 2002 Posts: 746 Downloads: 62 Uploads: 0	The bullet is showing the same spin that it would have while in the air (i.e. along the same axis). I guess it bounced off the ice, landed again, and then maybe its heat melted the ice around it, which provided lubrication that let it spin for so long? I'm not a physics prof, though. I'm just amazed that those guys weren't hit by ricochets - that bullet ended up behind them, just off to the left, after all.

10-25-10, 10:46 AM	#7
Penguin Ocean Warrior Join Date: Mar 2010 Location: Rheinische Republik Posts: 3,322 Downloads: 92 Uploads: 0	I also cannot explain it, so far I regard Angus' explaination as the most reasonable one. Some observations: - The bullet spin is definitely clockwise. Can any of you gun nuts identify the firearm and confirm that the barrell of this model provides a clockwise spin? - Each shot makes an impact onto the ice, however the bullet most likely bounces back when it is fired in a certain angle. This angle should be rather flat < 45°, otherwise the projectile would penetrate into the ice. - I guess the little wall of frozen ice and snow, where the targets are located, has something to do with it. The bullet gets reflected back towards the shoote/camera guy. So there must at least 2 reflections. - The colder the ice gets, the harder it is. I read somewhere, when the temperature reach -25° C, the hardness of ice would be the same as steel. There are no deformations visible, as I would have expected when a projectile gets reflected by a hard surface. So either it was not that cold, or the energy of the bullet melted the ice on the impact point enough to provide a "smooth" bouncing. Another good argument for free firearms for all, so we can all recreate this little experiment in the winter!