MythBusters Episode 38: "MythBusters Revisited"
Air Date: October 12, 2005
REVISITED: A body struck by a bullet will be propelled violently backwards. (From Episode 25)
re-busted
Even a .50 Caliber bullet does not have the momentum to knock a person backwards. If it were possible, the shooter would be knocked backwards as well – as per Newton’s Third Law.
REVISITED: Explosive decompression can occur when a bullet is fired through the fuselage of a pressurized airplane (From Episode 10)
re-busted
The Build Team tested the effect of air rushing past an open bullet hole, and surmised that the extra internal pressure caused by this would still not be enough to cause an explosive decompression.
REVISITED: You end up drier running in the rain than walking. (From Episode 1)
confirmed
When retrying the test in actual rain it was conclusively proven that the running test subject got less wet than the walking test subject. The use of artificial rain in the original test led to a false negative.
REVISITED: Holding a large sheet of plywood will slow a fall from a building enough to make it survivable. (From Episode 18)
re-busted
After testing the speed of updrafts with a special rig on Tory’s truck it was proven that you could not hold on to the piece of plywood if you were in free fall. A mere 45mph gust knocked it out of Tory’s hands; updrafts from skyscrapers reach upwards of 90mph.
SPINOFF: A black car heats up faster than an identical white car. (From Pilot 2)
confirmed
A fan wrote in and asked a follow up question: "Does the color of a car affect the way it heats up?". The MythBusters used two identical cars, one black the other white and left them both out in the summer heat with thermometers in both. By mid-afternoon the black car had heated up to a temperature of 135 °F while the white car topped off at 126 °F, almost 10 degrees cooler.
REVISITED: Running a car with air conditioning on is more fuel efficient than running with the windows down. (From Episode 22)
partly confirmed
The fundamental flaw in the MythBusters’ test was that the point where the drag becomes powerful enough to inhibit a car’s performance with windows down was inside their 45 – 55mph margin at 50mph. Going less than 50mph it is more efficient to leave your windows down, but going greater than 50mph it is more efficient to use your A/C.
REVISITED: A gas tank will explode when shot by a bullet. (From Episode 15)
busted
It has already been proven that when shot by a normal bullet a gasoline tank will not explode. However, if a gasoline tank is shot by a tracer round from a great enough distance so that the round can ignite with air friction, it will cause the gasoline to catch fire. By the time this happened the tank was so riddled with bullets (from previous tracers that were fired too close to ignite) that there was no contained pressure, but the MythBusters surmised that had the tank been properly enclosed, it may have exploded; but overall it remains extremely improbable.
If you ever revisit the bullet propelled body try a high energy low speed wide types of bullet. The idea is capacity to transfer energy to the body fast. I doubt they would propel a body back, but there is a difference. For example frecuently a 9mm bullet drills a hole thru tempered glass while a 380mm one can blow the glass away. There you have another myth to confirm. :). Try 380mm, .45 and different shotgun projectiles. Although I doubt they will propell backwards…..combine with body armor, or a big wide beltbuckle as means of getting energy transfer.
June 23, 2007 at 5:52 PMThe only difference the speed with which you tranfser the energy would make is how much time the target has to regain his balance or push back against something. As a best case, it’s easy to calculate how fast the target would go backward even if all energy were transferred instantly. I get something like half a foot per second at best.
And unless you can transfer the energy faster than you transferred it to the bullet in the first place, the shooter would be thrown back as violently as the target.
June 23, 2007 at 6:58 PMOne thing to consider with the argument that the shooter would be thrown back violently; with some weapons, the shooter would indeed be thrown back if not properly braced. However, I think this amounts to little more than losing their balance, not being pushed off of the ground.
For any bullet that would have enough momentum to do this, getting it all to impart on the victim would be difficult, especially without obliterating them.
June 24, 2007 at 3:35 AMI believe the test was flawed. The test targets were dead pigs. Some of the reaction that a living target would show would be an involuntary muscle reaction to the impact of the bullet, which could cause the body to fly backwards. The dead targets lacked this response.
June 26, 2007 at 10:19 AMThe running/walking in rain myth perplexed me in both the original myth and when revisited.
In a drenching downpour that totally soaks either individual before they reach their destination, the point is moot. However, In a constant lesser rain, it would seem logical that a person who spent less time in that rain would be drier than a person who spent a lot more time in that rain. Conclusion: Over a fixed length course the runner should be drier than the walker, who should be drier than the crawler, who would be drier than the person sitting in a lawn chair at the starting line. etc.
The test should have been over a fixed time period, rather than a fixed length. Seems like the results would be close to equal.
Either way, the old phrase”not enough sense to get out of the rain” is brought to mind!
June 27, 2007 at 3:55 PMI’m curious if CyberGuy has anyone in mind to use as a test subject? Perhaps the study can be carried to a country that still utilizes firing squads?
July 17, 2007 at 6:19 PMWhat about that famous photo of the man that was shot in the head, maybe in Vietnam, back in the day? I don’t think he flew backwards at all, and that was point-blank energy transference. I’m pretty sure that people don’t fly backwards when hit with bullets.
July 29, 2007 at 3:40 AMNo, a person might not fly back when hit by a bullet…depending on what kind of bullet is used. In the case of the guy in Vietnam, he was shot point blank with a full metal jacketed bullet. Thats why he didn’tmove, because it just went straight through him. Mythbusters need to try different kinds of bullets such as hollowpoints, or softpoints.
August 15, 2007 at 2:40 PMWith the exploding gas tank, does the amount of fuel in the tank matter? For instance, a tank with mostly fumes are more likely to explode than a full tank. This is the basis for welding a metal gas tank that is full.
August 21, 2007 at 6:48 PMWhile a single projectile(bullet) may not knock a person off their feet. I do believe a shotgun would, especially at close range with a heavy load, such as buckshot
September 23, 2007 at 3:36 PMRunning in the rain: no, the fixed length course is appropriate, since the context is whether you’d get more or less wet by, say, running home from a local store if caught in a sudden rain. The gain from spending less time in the rain outweighed the loss from presenting a larger cross-section (if the rain were coming straight down).
Gun throwing body back: the type of bullet doesn’t matter as much as you think. So long as the bullet stops within the body (doesn’t exit), all of its momentum and energy is transferred. The energy (1/2 mv^2) and momentum (mv) at the target is always LESS that that at the sending end because some is lost to air friction between, so yes the shooter will experience more jerk than the receiver (albeit with less damage!). A softer bullet might stop more rapidly, but the difference is milliseconds and on the human timescale not significant.
Hypothetical muscle reactions to being shot is a completely different matter, tho. Not likely to be tested by MB tho, even with live animals.
November 28, 2007 at 2:14 PMHas anyone ever heard of a _muzzle brake_?
December 21, 2007 at 10:51 PMshooting a hole in the side of an airplane that has been pressurized to 8 lbs. per square inch in itself is not even close to an accurate rendition of what would happen in a real situation. I think you’re forgetting about the 500 mph wind blasting over the hole creating a huge low pressure area. It would suck the contents from the imediate area out at the very least. And probably do more damage than that. certainly more than the unfruitfull excuse for a proper experiment you guys claim to prove it busted. Not that you guys can properly simulate those kind of circumstnces on the ground effectively.Maybe you can. Other than that one, I mean two episodes where you incorrectly carried out your experiment all the other shows I have seen were satisfying.THAT I HAVE SEEN. Please email me back your thoughts sincerely a fan
February 24, 2008 at 7:26 PMEvangelos Dimas
Try using a sawed off (18″+) double barreled shotgun and see how a body flies back when hit with both barrels at close range with two 3″ magnum 00 buckshot. The force on the shooter is focused on a smaller area and they are braced for it, absorbing the kick in their arms, shoulders back and legs. Beside the fact that the weapon has a butt/kick pad. They will experience one hell of a jolt but will be able to withstand it. A person on the receiving end will be hit over a large area and would not be able to take it. While the amount of force would be measurably less than the “kick” due to it being spread out, the poor soul who just got shot would be knocked off their feet and thrown backwards several feet. I’ve seen it.
March 26, 2008 at 10:46 PMhi i think that the preasure inside of the plane needs to be matched as the crusing altitude of a plane.
May 12, 2008 at 2:52 AMwith the shooting the gas tank if the engine was running there would have been a diffrent result. also if you shot at an engine there would have been a diffrent conclusion.
August 16, 2008 at 6:45 AMHow come Adam puts the verdict in the exploding gas tank myth “CONFIRMED”? The higher the octane, the more the dangerous they are when shot by tracer rounds.
August 19, 2008 at 5:12 PMIn the Plywood Builder myth the revist showed that there was lift. The reason Tory couldnt hold on to the plywood is that he was anchored to the ute, wheras the wood continued to rise.
August 31, 2008 at 10:39 PMI dont think that the myth will be confirmed even with this change as a person wont be able to effectively steer the plywood while in the air or slow enough to land without dieing, but is still a slight flaw in the testing.
A gas tank will explode when shot by a bullet: confirmed. its been done in iraq with one round APIT from an M2 .50 cal. ya’ll realy need an on hand weapons guru for accurate testing on such myths
October 5, 2008 at 8:30 PMIts a living bodies involuntary muscular and nervous reactions to being hit by a bullet that causes it to move not the force imparted by the bullet so it wouldn’t work with a dead pig, try sticking a pin in someones butt unexpectedly, it causes them to move quickly but its not the force imparted by the pin involved that does it.
October 19, 2008 at 10:24 AMSo a bullet wont explode it. But what about the rag stuffed in the gas tank opening set on fire? Will that blow the car up?
You see it all the time on the movies.. but will it really work?
October 24, 2008 at 10:05 PMI think the mythbusters were right with the gas tank and if someone doesnt like that then make your own show or video and show us all
March 20, 2009 at 11:31 PMOn Hollywood style back-flip when shot by a bullet: There is a point in space, called mass center. The point is placed at a distance inverse proportional to the mass of each body, so the mass center will be very close to the human body even when the bullet just leaves the gun’s barrel. That point will carry on it’s movement no matter if the collision between the two bodies is elastic, plastic or anything in between. When the bullet stays in the body, both of them will travel with the speed of the mass center, and that speed will be extremely low, due to the huge difference in mass.
Another way to look at the problem is computing the impulse of the bullet and of the bullet-body assemble (assuming the body was static, so it had zero impulse). In a collision, the total impulse is constant. Then, all the impulse of the bullet is passed to the body; but impulse being speed times mass, and the impulse being the same, the speed after collision will be the speed of the bullet times the rapport between the mass of the bullet and the mass of the body. That rapport is about the same if not of greater order of magnitude than the speed of the bullet and therefore the final speed will be extremely low, practically zero.
The best approach to this problem is, actually, energetic. The kinetic energy of the bullet is the same with the total energy of the bullet-body assemble. The body has huge potential energy (inertial mass) and not all energy of the bullet is passed to the body (a lot is used to heat the area of contact, and a small part is used in deforming the shell), therefore the body will not move.
The theory of jumping out of sheer shock, or due to an involuntary muscular reaction, is just as unbelievable as the back-jump itself: if a human being is capable of such jumps, we will have 20-30 meters of long-jump olympic records instead of merely 9 meters… No matter whether a muscle is contracted voluntarily or not, the same maximum amount of force will be produced. The human physiology is not capable of those movements, as seen in Hollywood action movies.
A general comment on you, guys (and I am referring to Adam and Jamie): please, PLEASE, bring some physicists on the show that will explain plainly and correctly why some myths could not possibly happen… or at least to correct your explanations (I have seen explanations that were basically true, but had wrong “components”).
Good show, tho! :)
April 21, 2009 at 10:25 AMThis is a response to Cyberguy..
June 11, 2009 at 5:45 PMWhen the “involuntary” response to the bullet hitting you, makes you jump backwards.. this is still proving the myth busted because the actuall force of the bullet isn’t causing you to fly backwards, it’s your body’s response to the bullet hitting you.
So the test were right and the myth still busted.