Mythbusters 7x10 "Curving Bullets" - Discuss and Grade
- Thread starter Hermiod
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I'm eagerly awaiting the "Harry Potter" episode - can you really move things with a magic wand? and the "Star Wars" episode - can you slice through steel with a light saber?
anyone with a bit of common sense would know that a bullet moves too fast to be affected by a flick of the wrist . . . it's out of the barrel before you can even start the flick . . . the only way I see it working is with a curved barrel and a bullet that's like a miniature golf ball
like how some paintball markers put a backspin on the paintball
like how some paintball markers put a backspin on the paintball
I guess the idea behind the Wanted thing is that if you impart a lateral vector to the gun's motion while the bullet is moving through the chamber, that will cause it to continue moving sideways once it leaves. Which wouldn't cause it to curve, of course; at most it would follow a slightly diagonal path, probably not even that since, as backstept points out, the amount of lateral motion imparted on the bullet by human muscles would be trivial compared to the forward motion imparted by the exploding gunpowder. But I can see where the idea that this might work would come from.
And that's why it's a myth worth testing and debunking -- because it seems to the uninitiated as though it could work. It's like the one about birds taking flight inside a truck -- a little physics reasoning or calculation can give you a definitive answer without needing the test, but most people don't know their physics that well and need to be shown why it wouldn't give the result they might intuitively expect.
And that's why it's a myth worth testing and debunking -- because it seems to the uninitiated as though it could work. It's like the one about birds taking flight inside a truck -- a little physics reasoning or calculation can give you a definitive answer without needing the test, but most people don't know their physics that well and need to be shown why it wouldn't give the result they might intuitively expect.
I hope this is just the B myth and that the A myth is something more interesting.
Seems they're heading that way, doesn't it? I rarely watch Mythbusters anymore due to the fact that it seems like somes of the myths are just "well duh" and others are "Oh come on, you're pulling this out of our ass to fill out the time".
Hell, if we're going to test stupid TV and movie gun myths, lets see if it's possible for a woman to reload a revolver by bouncing her boobs. Hey, I saw it on TV, so we better test it to make sure it can be done.
I don't understand the objections. Most of the myths they've tested over the years have been obviously absurd to anyone with a halfway decent knowledge of physics, but there are people who buy into them anyway. Will a cell phone blow up a gas station? Will dropping a hammer in the water before you hit save you from being killed on impact? Can a penny falling off the Empire State Building kill someone below? Does a duck quack magically lack an echo? All totally ludicrous ideas if you think about them, all tested in the show's first season. And exposing their absurdity was worthwhile because there are people out there who actually believe these things.
The "curve the bullet" bit is a myth, but you can move fast enough to affect the path of the bullet due to dwell time. After the primer ignites, it takes time for pressure to build and the bullet to begin moving, and then for the bullet to leave the barrel. If you move the weapon during this period, you will miss your aiming point. That's why follow through is so critical. You have to keep the sights on the target even after you've fired so that you don't adversely affect the bullet's path. If you start looking for the hit or just relax when you fire, you will miss your aiming point.
I'm sure most people accept that the curving bullets as seen in the movie couldn't happen. But I bet there are still a LOT who think if you could jerk the gun fast enough, or track the bullet at a great enough distance, you could see some curving action after all.
In any case, any time you have an opportunity to teach the public a little basic science, it's a good thing in my book.
In any case, any time you have an opportunity to teach the public a little basic science, it's a good thing in my book.
I'm wondering how they're going to test whether the bullets actually curve in flight as opposed to just going diagonally. I guess a high-speed camera would be sufficient to catch the flight of the bullet.
Sonic booms!!!!
More than the others, this really feels to me like an obviously implausible myth. I'll watch it, but it's currently DVRing.
"Curving the bullet" to me would seem to violate several physical laws.
Most notably the ones that say objects move in straight lines.
Like, if the sun right now vanished -it's gravity well with it- the earth wouldn't continue to move in a circular pattern it'd shoot off in a straight line.
You can't "curve" a bullet. Now sure, you can curve things like bowling balls (but they're round) and baseballs (also round) but curving bullets? Seems like it'd be impossible to do.
Most notably the ones that say objects move in straight lines.
Like, if the sun right now vanished -it's gravity well with it- the earth wouldn't continue to move in a circular pattern it'd shoot off in a straight line.
You can't "curve" a bullet. Now sure, you can curve things like bowling balls (but they're round) and baseballs (also round) but curving bullets? Seems like it'd be impossible to do.
It's easy to curve a bullet, extremely so, vertically. Just point it at an upward angle and you'll get a parabolic flight path.
Doing it horizontally, however, is unlikely, without some sort of extremely precise guide, or a curved barrel.
Doing it horizontally, however, is unlikely, without some sort of extremely precise guide, or a curved barrel.
"Sonic Boom Sound-Off": Too much emphasis on Adam's physiological distress during flight training. I also don't care for their graphics illustrating a sonic boom -- it wasn't portrayed right, as a conical pressure wave forming ahead of the projectile and sweeping back. It just showed a field of expanding sound waves moving backward from the rear of the bullet, which is totally wrong. The sound waves are moving forward and outward, but the bullet is outpacing them, so they compress together into a conical shock front.
Looks like they got that head-on high-speed footage of the approaching bullet going down the glass corridor by putting a mirror at the end and pointing a camera at it. In the final shot, when the glass was just half an inch from center, it looked like the bullet or shrapnel hit the mirror and broke it.
Oh, and they built another of their little red houses out in the middle of nowhere! Aww.
It was hilarious watching the sonic booms break everything but the glass. The only glass that broke was a sheet that was confined within a frame in a solid surface and forced to vibrate past its breaking point (and that slo-mo footage of the window warping and shattering was really cool). Most of the rest of the glass was more out in the open, so there was more room for the force of the shock wave to move around them rather than being forced through that opening as with the window, and the glass itself was more free to move around and absorb that force by motion rather than breakage. So I'd say this myth is only true of panes of glass. And only in extreme circumstances, as shown.
"Bend a Bullet": Ahh, I see, the idea is that the bullet curves around an obstacle to hit a target. So the Mythbusters determine success by hitting the target and missing the obstacle. The way it was shown in the movie clip was even more ludicrous than what I'd imagined. I was thinking the idea was that it would be like a curve ball, a single continuous curve. Instead, it showed the bullet following kind of a question-mark-shaped trajectory, heading straight for Ms. Jolie's celebrated face, then sentiently swerving right to avoid it before circling back to the left toward the target. That's just silly.
We finally get a spoken acknowledgment of Kari's pregnancy -- once she's six months along! I'm feeling a little uncomfortable about her being anywhere near all these guns and explosives at this point, even with a bulletproof vest.
Oh, so that's how they test curvature -- holes in five paper sheets. Clever. But they must already know it's physically impossible, and I wish they'd explained why. A curved path is the path of a body under continuous sideways acceleration. The sideways acceleration on the bullet ends as soon as it leaves the barrel of the sideways-moving gun. From that point on, it can only travel in a straight line (aside from the fact that it's being curved downward by gravity). A curve ball curves because it's rotating and has raised surfaces, and the vortex creates a vacuum on one side, generating that unbalanced force pushing it sideways. The only way you'll get a bullet to curve (any way other than downward) is by putting some kind of spin on it, and then only if it has the irregularities needed to create a vortex. And even so, you wouldn't get the ?-shaped curve from the movie scene.
But then, the movie did show specially engraved bullets, so maybe that was the idea, and that's what the guys tested to finish off. And it made no difference, at least over the relatively short distance of the firing range. Besides, as the guys said, the rifling makes the bullet spin so that the gyroscopic effect will keep it from tumbling and make it stay straight -- and the slo-mo shots in the movie showed the magic bullets spinning in just the way that should keep them straight. So it's inept physics on multiple levels.
And Grant resurrects the sword-swinging robot. I'm surprised how rusty they let it get.
Looks like they got that head-on high-speed footage of the approaching bullet going down the glass corridor by putting a mirror at the end and pointing a camera at it. In the final shot, when the glass was just half an inch from center, it looked like the bullet or shrapnel hit the mirror and broke it.
Oh, and they built another of their little red houses out in the middle of nowhere! Aww.
It was hilarious watching the sonic booms break everything but the glass. The only glass that broke was a sheet that was confined within a frame in a solid surface and forced to vibrate past its breaking point (and that slo-mo footage of the window warping and shattering was really cool). Most of the rest of the glass was more out in the open, so there was more room for the force of the shock wave to move around them rather than being forced through that opening as with the window, and the glass itself was more free to move around and absorb that force by motion rather than breakage. So I'd say this myth is only true of panes of glass. And only in extreme circumstances, as shown.
"Bend a Bullet": Ahh, I see, the idea is that the bullet curves around an obstacle to hit a target. So the Mythbusters determine success by hitting the target and missing the obstacle. The way it was shown in the movie clip was even more ludicrous than what I'd imagined. I was thinking the idea was that it would be like a curve ball, a single continuous curve. Instead, it showed the bullet following kind of a question-mark-shaped trajectory, heading straight for Ms. Jolie's celebrated face, then sentiently swerving right to avoid it before circling back to the left toward the target. That's just silly.
We finally get a spoken acknowledgment of Kari's pregnancy -- once she's six months along! I'm feeling a little uncomfortable about her being anywhere near all these guns and explosives at this point, even with a bulletproof vest.
Oh, so that's how they test curvature -- holes in five paper sheets. Clever. But they must already know it's physically impossible, and I wish they'd explained why. A curved path is the path of a body under continuous sideways acceleration. The sideways acceleration on the bullet ends as soon as it leaves the barrel of the sideways-moving gun. From that point on, it can only travel in a straight line (aside from the fact that it's being curved downward by gravity). A curve ball curves because it's rotating and has raised surfaces, and the vortex creates a vacuum on one side, generating that unbalanced force pushing it sideways. The only way you'll get a bullet to curve (any way other than downward) is by putting some kind of spin on it, and then only if it has the irregularities needed to create a vortex. And even so, you wouldn't get the ?-shaped curve from the movie scene.
But then, the movie did show specially engraved bullets, so maybe that was the idea, and that's what the guys tested to finish off. And it made no difference, at least over the relatively short distance of the firing range. Besides, as the guys said, the rifling makes the bullet spin so that the gyroscopic effect will keep it from tumbling and make it stay straight -- and the slo-mo shots in the movie showed the magic bullets spinning in just the way that should keep them straight. So it's inept physics on multiple levels.
And Grant resurrects the sword-swinging robot. I'm surprised how rusty they let it get.
I was surprised that just for the sake of completeness they didn't let the gunslinging robot take one crack at the unrifled gun.