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9 Laws of Physics That Don't Apply in Hollywood

Posted by Hemos on Tue Mar 06, 2007 11:44 AM
from the relativity-also-out dept.
Ant writes "Neatorama lists nine laws of physics that don't apply in Hollywood (movies and television/TV shows). In general, Hollywood filmmakers follow the laws of physics because they have no other choice. It's just when they cheat with special effects that people seem to forget how the world really works..."
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  • by Anonymous Coward on Tuesday March 06 2007, @11:46AM (#18250888)
    AKA. Mythbusters.

    The "Hollywood special" from a few moths back.

      • Copper doesn't spark (Score:5, Informative)

        by spun (1352) <loverevolutionar ... com minus distro> on Tuesday March 06 2007, @12:12PM (#18251338) Journal
        From the intuitor.com site mentioned in a post below:

        Typical handgun bullets are made of copper-clad lead or lead alloys. They simply don't create bright flashes of light when they strike objects, even if the objects are made of steel. In the chemical industry it's commonplace to limit maintenance workers to copper-alloy or lead hammers when they are working in areas where flammable fumes may be present. Hammers made of these materials do not produce sparks when they strike objects, while steel hammers can. If you've never noticed this phenomenon with steel hammers, don't be surprised, the sparks generally are barely visible even under ideal lighting conditions.

      • Pet Gun Peeve (Score:5, Informative)

        by Kozar_The_Malignant (738483) on Tuesday March 06 2007, @12:18PM (#18251440)
        On a related firearms note, they always f*** with the depiction of double action revolvers. When the actor checks to see if it's loaded, they release the catch and swing the cylinder out. They always spin it, and they always dub in the clicking sound of spinning the cylinder of a single action revolver (think cowboy Colt Peacemaker, where the cylinder doesn't swing out). In real life, they don't make any sound when you do that.
      • by pclminion (145572) on Tuesday March 06 2007, @12:40PM (#18251836)
        I got a chance to fire some incendiary rounds recently. Talk about sparking.
              • by pclminion (145572) on Tuesday March 06 2007, @04:28PM (#18255084)
                Perhaps he is a scuba diver?
                • by 99BottlesOfBeerInMyF (813746) on Tuesday March 06 2007, @04:57PM (#18255428)

                  Mythbusters tried this. Pretty much any high-velocity (supersonic) round is going to disintegrate when it hits water.

                  I've watched mythbusters (including that episode) and they can be pretty amusing, but please don't confuse them with actual evidence. It is a TV show mostly about making stuff blow up. I know from personal experience that bullets do not "disintegrate" on contact with water from normal firearms. You can watch incendiary rounds as they go through the water (although they are probably subsonic). I had a friend accidentally shoot himself in the foot with a .22 when he fell through the ice on a pond and the bullet certainly went through quite a bit of water. I once saw a jackass shoot a carp with a shotgun, while it was under about 24 inches of water, and the rounds certainly reached it.

                  You'd have to have a VERY low angle to the water to suffer a richocet.

                  As young kids we routinely used an old gravel quarry as a shooting range and it was mostly full of water. Someone standing on a typical shoreline and firing at someone or something maybe 20 feet out would experience rounds deflecting off the surface and hitting things on the other side. It is one reason hunters are cautioned about shooting rifles towards water. A rifle round can hit the water and skip half a mile across to the far shore and kill someone.

                  Again, mythbusters is TV, do not try to take anything they "prove" as some sort of fact. Half the time, they don't seem to have any real intention of finding out if something can happen, just making a big mess and some explosions. It is entertainment, not science.

      • by AJWM (19027) on Tuesday March 06 2007, @01:05PM (#18252250) Homepage
        Copper doesn't spark. Iron sparks -- try setting fire to a ball of steel wool sometime. I've heard that some kinds of cheap Eastern block ammo was jacketed in some kind of soft steel rather than copper (cheaper, but kind of rough on the gun barrel), that would spark. Mind, if the shooter's not using an AK-47 or something designed for such ammo, it's bogus.

        • I think the ammo you're talking about is not jacketed in steel, but cased in steel. And yes, some people believe it to be significant rougher on guns than conventional copper-cased stuff, but not because of the bullet going down the barrel proper, but due to the damage that the steel case may be doing to the chamber during loading and extraction.

          You used to find this stuff under the "Wolf" brand name, and it was mostly made in Russia and some other ex-WP countries. I think Wolf may be trying to move upmarket and has ditched the steel-cased stuff, recently though.

          At any rate, the bullets in that stuff were pretty standard at least that I ever saw, but instead of using a brass case, as is used in most Western countries' ammunition, they went with steel cases, covered in some sort of paint and lacquer (assumedly for rust-proofing). There were a number of issues with it, particularly in close-tolerance weapons. First was just the threat of damage to the chamber because it's a harder metal (although I have doubts about this), more significantly was that if you blasted a bunch of it off rapidly, you could get the gun's chamber hot enough to start melting the lacquer off of the cartridges, and over time, build up a layer of lacquer inside the chamber, that would change its dimensions, and lead to feed problems, particularly if you switched back to other types of ammo.

          I know a number of people who got burned by the lacquer-buildup problems, because they had AR-15 style rifles with tight-tolerance chambers (the .223 Remington chamber, as opposed to the 5.56mm "NATO Chamber" or the compromise "Wylde Chamber").
      • Unless something is really wrong with the powder charge you're using in the gun, there shouldn't really be any "sparks" coming out of the end of the barrel, at least with modern smokeless powder.

        The muzzle flash that comes out of a gun is superheated gas, the product of the powder's rapid combustion; a "spark" would indicate some form of burning / incandescently-hot large particles, and there really shouldn't be anything that big left after combustion. If there are big (enough to be visible) chunks of burning powder coming out the muzzle of your (modern) gun, you have some sort of problem. I'm not sure whether you'd even technically call a real muzzle flash a "flame," since it's not really burning anymore; the majority of the chemical reaction that launched the bullet, ran to completion in the first few fractions of a second after the primer detonated. On weapons with short barrels, the muzzle flash is visible because the exhaust gases exit the muzzle out into the atmosphere before they've had a chance to cool below the point of incandescence. I don't think there's really anything in the way of actual 'combustion' still going on.

        Muzzle flash is another thing that Hollywood tends to exaggerate; although it's definitely an issue in real life, it's more difficult to see on a bright, sunny day than you'd expect from watching action flicks. FWIW, I think that they simulate muzzle flashes by using propane or methane, particularly for automatic weapons, in movies.
      • by cant_get_a_good_nick (172131) on Tuesday March 06 2007, @01:18PM (#18252474)
        5.62 Millimeter...
        Full... Metal... Jacket...!!!

        Sorry, couldn't resist. One of my favorite movies of all time.
  • by yohanes (644299) on Tuesday March 06 2007, @11:47AM (#18250908) Homepage Journal
    It seems that we have discussed this kind of things so many times. Hollywood are not meant to learn about real world. It is about entertainment.
    • by SengirV (203400) on Tuesday March 06 2007, @12:19PM (#18251448)
      Which is why it's pure comedy gold when they talk about politics.
    • by squiggleslash (241428) on Tuesday March 06 2007, @12:26PM (#18251576) Homepage Journal

      Yes and no. There has to be a willing suspension of disbelief, and frequently Hollywood (and television) assumes that the number of people in the viewership of a particular program is so low it quite happily removes all semblance of reality for that "minority" to the point, not really caring that the entire movie looks utterly ridiculous as a result for that group. What's bizarre to me is how rarely it's necessary for the plot or understandability of the end story for them to do that.

      It would probably serve the plot well for quite a few films if a normal car's cruise control allowed the car to drive unmonitored, or if newspapers talked and responded to spoken database queries. They don't do either because almost the entire audience knows that there is too large a gap between reality and fiction for those specific examples. But if it involves computers, explosions and weapons, gravity, or even breaking glass, anything goes... Hell, sometimes if it's something that everyone knows today is ridiculous but once upon a time was a black-art, they'll get away with it because it's a cliche. Don't forget to hang up the telephone before they're able to trace the call!

      It's worse when so-often the inaccuracies are basicly a Deus Ex Machina to get the hero out of a problem. If Chloe wasn't able to trace the call through the binary, Jack wouldn't know the terrorist's address, and so wouldn't be able to cross Los Angelas in twenty minutes at mid-day to prevent them from using the code they downloaded from the satellite to their PDAs to activate the chemical weapons.

    • by Jorgandar (450573) on Tuesday March 06 2007, @01:17PM (#18252458)
      Imagine how short movies would be if they all followed the laws of physics...Hero fires a handgun at enemy, ducks under a table, gets shot at, runs and jumps off a ledge to the ground below, twists an ankle because the fall was about 5 feet, limps away, and gets killed by gunfire. End of movie.
    • by Hoi Polloi (522990) on Tuesday March 06 2007, @01:52PM (#18253068) Journal
      I have to admit, if Hollywood was realistic and didn't have sound in space it would make sci-fi action films pretty dull. It would just have a lot of background music so I let them off on that one.

      BTW, "2001, A Space Odyssey" was true to the no sound in space law and used it to dramatic effect. All you heard was the dull whir of systems in the pods or the astronaut's breathing.
  • Intuitor (Score:5, Informative)

    by imaginaryelf (862886) on Tuesday March 06 2007, @11:48AM (#18250930)
    I've always enjoyed intuitor dissect movie physics for some of the more popular movies.

    http://www.intuitor.com/moviephysics/ [intuitor.com]
  • by Mark Maughan (763986) on Tuesday March 06 2007, @11:50AM (#18250978)
    You don't see people's skeleton glow when they are being electrocuted.
  • First, let me preface this by saying that Hollywood is fiction. I think when we see the tanker truck blow up, the Power Rangers jump-kicking someone in the chest, or Neo fly through the air like Superman, we understand it's fiction. It's called "suspension of disbelief." It's what makes movies enjoyable. No one is really going to think that these things happen as regularly (or at all) in real life as they do in the movies.

    That being said:

    Explosions on the battlefield go boom right away, no matter how far away spectators are. Even a small thing, like the crack of a baseball player's bat, is simultaneous with ball contact, unlike at a real game.

    In most instances that come to mind, the director takes care of this problem by zooming you in on the Volcano, shell explosion, or baseball hit. Once you hear the sound at the source, the director usually cuts away to the actors after the sound has arrived. (As can usually be surmised by the ash and dirt flying at the camera.)

    Hollywood always gets this one wrong. On film, thunder doesn't follow lightning (as in real life, because sound is slower); they occur simultaneously.

    To the human ear, they are effectively simultaneous if the lighting crack is close enough to the observer. Considering how LOUD the director usually chooses to make the thunder, I don't think it's that bad of a summation. How about we start worrying why the actors aren't taking shelter?

    And because radioactive things emit light only when they run into phosphor - like the coating on the inner surface of a TV tube - you don't really need to worry.

    This is actually incorrect. Radioactive "things" can emit light through two other methods:

    1. They grow physically hot enough to glow red-hot or white-hot.

    2. They heavily ionize the air around them, creating pretty streaks and rainbows.

    However, the green-glow often seen in movies and cartoons does usually require the presence of phospher.

    So, when you see a gal kick someone across the room, technically, the kicker (or holder of a gun) must fly across the room in the opposite direction - unless she has a back against the wall.

    Or... the kicker could be properly grounded. If the kicker is properly braced against the ground, it's not impossible to send an unbalanced opponent off his feet. The fact that you can pick an opponent up and toss him in a single motion demonstrates that. That's not to say that the exact situation of many fights isn't ridiculous (excuse me, rediculous), but the physics of the situation don't prevent a kicker from delivering a blow hard enough to knock someone off their feet. Perhaps even to the point of sending them flying. (Though it's unlikely that it would be to the point of many kung-fu movies on strings. There's only so much structural capacity in the human body. After that, you start breaking your own bones.)

    Now when they miss their target and don't go flying across the room... :-P

    But in the movies, buses and cars shouldn't be able to jump across gaps in bridges, even if they go heavy on the accelerator.

    Unless, of course, there is some sort of incline for a takeoff (ever notice how the Duke boys always manage to find that conveniently placed incline?) or the second section is lower than the first, thus allowing for the jump to complete depsite the drop in altitude. (As the camera appeared to make the situation in Speed.)

    The problem, though, is that their voices don't change. In reality, if you slow down motion by a factor of two, the frequency of all sounds should drop by an octave.

    Smash cuts don't exist in real-life, either. Yet we don't complain about those. Slow motion is an entirely artistic thing, and is not related to the physics of the situation. At all.

    Pretty much the rest of his arguments

      • But the thing that was most ridiculous about this scene was that it was a bus. It's one thing when a Charger jumps a gap with a ramp. A bus, even going very fast, is going to have plenty of time where its front end is falling while the back end is still supported and even going up on the ramp. The result is going to be angular momentum imparted to the bus. So what should have happened is the front end of the bus dipped down faster than the center of mass, causing it to miss the lower section and end up landing upside down on the ground below.

        Well, but you do realize they did actually jump a bus, right? This scene was not done through CGI or with a helicopter towing a bus over the gap. The bus really jumped through speed and momentum alone. The gap was not there - it was added later digitally (or rather, the freeway was erased) - but the bus did jump that distance.

        Granted, it was a) a specially modified stunt bus on a ramp, and b) pretty much totally destroyed by the jump. But it's proof that you can jump a bus. It would not behave exactly as you describe. Keep in mind most buses are back-heavy, so with enough speed to keep the bus relatively level as it went over the ramp, the rear would actually drop as it moved through the air, not the front. With a short enough jump (as is all a bus is really capable of), the bus would probably come close to landing on all four wheels when all is said and done.

        (Side-note - according to Wikipedia, they actually had to shoot the jump twice because on the first shot, the bus made the jump too smoothly, which supports what I'm saying above.)
        • by ceoyoyo (59147) on Tuesday March 06 2007, @01:32PM (#18252744)
          Um... recall Galileo... the back of the bus being heavier will not cause it to fall any faster than the lighter front. Neglecting air resistance, but with something the mass of a bus that's not so bad an assumption.

          You're right, they DID jump a bus. BUT, they had a special kicker on the end of the ramp that dropped after the front wheels went over. Watch the scene again... see how the front wheels seem to leap up? There's a documentary around somewhere showing how everything worked and the actual bus jump, but I can't remember where I saw it or what it was called.

          Even a car will always land hard on its front wheels (if you're lucky) or its nose or roof (if you're not) after going off a static ramp.
  • How about the fact that there is no such thing as a perfect vacuum?

    Hollywood movies suck so much it seems like they violate this one.
  • by Anonymous Coward on Tuesday March 06 2007, @11:52AM (#18251024)
    Time is rarely shown as continuous, forward moving, and in real time.

    They are always using edits, skipping stuff and even going backwards and forwards. Really makes it hard to enjoy a film with your sense of reality totally shattered.
  • Umm... (Score:5, Insightful)

    by geoffspear (692508) on Tuesday March 06 2007, @11:53AM (#18251034) Homepage
    If you're going to write an article about the laws of physics, shouldn't you actually understand the laws of physics? "Equal and opposite reaction" doesn't mean that when I kick someone and they go flying in one direction, I must go flying in the opposite direction at the same speed, unless I had no momentum toward them before impact. In which case, umm, it would be kind of hard for me to hit them.
    • Re:Umm... (Score:5, Funny)

      by 93 Escort Wagon (326346) on Tuesday March 06 2007, @11:57AM (#18251094)

      If you're going to write an article about the laws of physics, shouldn't you actually understand the laws of physics?
      Dude, hello - this is Slashdot? People "knowledgeably" comment on science here all the time without benefit of actually understanding the subject.
  • #4 and #5 (Score:5, Insightful)

    by MeanderingMind (884641) on Tuesday March 06 2007, @11:57AM (#18251092) Homepage Journal
    I've got two complaints about #4.

    1) The point of the Matrix was to bend the laws of physics. It was rather explicit.

    2) The author obviously never watched Bruce Lee in action. If you plant yourself correctly you can send people flying across the room without moving an inch yourself. However, if you're in midair you certainly can't without the mentioned conversion of momentum.

    Also concerning #5.

    1) If it's a hole with level ends on both sides, it is entirely impossible to jump it on car without a ramp or other device to add a vertical component to velocity. However, in the event of a bridge being raised for a boat, the angle can potentially allow a vehicle to "jump" the gap. Is it likely or feasible? Not particularly, but it is possible.

    2) This could have been expanded to include the "Bombs do not drop straight down" category of gravitational violation. A plane flying at high horizontal velocity v over a stationary target is not capable of dropping a bomb without horizontal velocity. Unless it fires the bomb backwards at a relative velocity -v, in which case we can have a semantic argument over whether the bomb is being dropped or fired.
  • Other laws (Score:5, Insightful)

    by 91degrees (207121) on Tuesday March 06 2007, @11:58AM (#18251112) Journal
    Fast paced music doesn't really play when something exciting happens. Not everyone in real life looks like a hollywood actor. If people speak in a foreign language, you don't actually see an English language translation at the bottom of the screen. I tend to be pretty easy going on most non-realism since it is just there to tell a story. If the plot relies on a complete failure to grasp some basic fundamental of physics, (e.g. The Day After Tomorrow), I tend to be a lot more critical.
  • Wile E. Coyote (Score:5, Interesting)

    by kfstark (50638) on Tuesday March 06 2007, @12:00PM (#18251144) Homepage
    I am a firm believer in the ability to break the law of gravity.

    I was out surfing and paddled into a wave. When I jumped up to my feet, I missed the sweet spot of the wave and ended up on the breaking part instead (ie. not a good location). To this day I swear the wave dropped out from under me followed by the board while I hung there in midair. Misquoting Douglas Adams, "gravity finally looked my way and wondered what the hell I was doing" and down I went. The couple of people who saw it were sure I was surfing a board made by "Acme".

    It was a really bizarre physical sensation I have not been able to adequately explain. (or recreate).

    --Keith
    • Re:Wile E. Coyote (Score:5, Interesting)

      by inviolet (797804) <pineminder@[ ]oo.com ['yah' in gap]> on Tuesday March 06 2007, @12:37PM (#18251762) Journal

      I was out surfing and paddled into a wave. When I jumped up to my feet, I missed the sweet spot of the wave and ended up on the breaking part instead (ie. not a good location). To this day I swear the wave dropped out from under me followed by the board while I hung there in midair. Misquoting Douglas Adams, "gravity finally looked my way and wondered what the hell I was doing" and down I went. The couple of people who saw it were sure I was surfing a board made by "Acme".

      That's possible: the water could pull the board downward faster than 9.8m/s/s due to surface tension. The board is somewhat 'stuck' to the surface of the water.

      The same effect could explain how the water itself fell faster than 9.8m/s/s: wave action elsewhere created a suction below the water, such that atmospheric pressure above the water pressed down on it (and on the board), adding to the downward accelleration already provided by gravity.

  • by swschrad (312009) on Tuesday March 06 2007, @12:04PM (#18251188) Homepage Journal
    basically because the western has been out of favor for a long time.

    I refer, of course, to the infamous 250-shot revolver.

    basically, back in the black and white days, nobody EVER reloaded their guns.

    you never saw any recoil, either, but that's because those movies were made when men were MEN and sheep ran scared, and those actors were truly made of steel, riding horses at a full gallop and able to hit a bad guy in the back of the head from 300 yards with a pistol with a four-inch barrel. and their arms never moved when the revolvers and rifles fired.

    and the scenery along the trail repeated itself every 60 yards or so, but then we're not going for the top 2,000,327 movie lies here, are we?
    • I refer, of course, to the infamous 250-shot revolver.

      basically, back in the black and white days, nobody EVER reloaded their guns.

      Hollywood still does that. But with modern weapons being capable of holding an indeterminate size of clip (as opposed to the standard six-shooter), it's difficult to call them on it. They just throw a few clip ejections into the fray to make it seem like the characters are really reloading.

      You can kind of call them on double-barreled shotguns, but Hollywood has slowly phased those out for pump-action weapons. Of course, those are similarly amusing, but for different reasons. I was just watching an old episode of Sliders the other day where the characters are carrying pump-action shotguns. Every time they cut to a new scene, the characters would re-pump their shotguns. Which was rather amusing considering that they hadn't fired a single round...
  • by Timesprout (579035) on Tuesday March 06 2007, @12:04PM (#18251200)
    I am becoming more convinced that people watch series like 24 or The Unit and are mistakenly under the impression that they are accurate representations of US capability. Vast computing power at everyones fingertips, satellites retasked at a moments notice for real time video, instant communication anywhere in the world, highly sophisticated gadgets that never fail in the field and of course clairvoyant and all knowing agents. No surprise the US has been so gung-ho lately.
  • 1 Law of Computers That Doesn't Apply in Hollywood: Computer passwords cannot always be guessed in 3 tries.
  • by Animats (122034) on Tuesday March 06 2007, @12:09PM (#18251296) Homepage

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  • Middle C (Score:4, Funny)

    by OhEd (877009) on Tuesday March 06 2007, @12:15PM (#18251374)
    The article says that the frequency of middle C is 256 Hz. Sorry, no, it's approximately 261.6Hz. Analysis: the article is quite flat.
    • by AKAImBatman (238306) * <akaimbatman.gmail@com> on Tuesday March 06 2007, @11:55AM (#18251068) Homepage Journal

      The fluid promptly freezes because, as we all know, outerspace is really, really cold.

      That one bugged me about a recent Battlestar Galactica, as well. Inside the room, the characters were freezing because the air was leaking away. (Thus cooling the room.) I can accept that. But once they're blasted into space? Not a chance of freezing. No air for cooling == no loss of heat. (Actually, you can still lose it slowly through black-body radiation, but that's another topic.) Human skin is pretty good at holding pressure, so the big things are:

      - Don't hold your breath (unnecessary internal pressure)
      - Close your eyes (they're more susceptable to decompression)

      See the research into the Space Activity Suit [wikipedia.org] for more info.
      • Wrong. As you sit in front of your computer, you exchange heat with your environment in three ways simultaneously: (1) conduction, (2) convection, (3) radiation.

        The part you are referring to is heat transfer mechanism (1), conduction, as your body heats cooler air molecules around you. Mechanism (2), as occurs when those heated air molecules rise toward the top of the room making room for cooler ones, also requires air.

        However, mechanism (3), the most effective of the three, does not require any medium at all. You, like all baryonic matter, emit electromagnetic radiation with frequencies and intensities as described by blackbody radiation, dependent on temperature. An object twice as hot gives of 16 times as much heat in radiation per unit time.

        Normally, when sitting in front of your computer, you are radiating like mad, and so losing heat. However, so are the walls of your apartment. Those walls, being nearly the same temperature as you are, heat you to a large degree, making up for the heat that you are losing to radiation. Hence if, on a cold night, you are walking down a hallway in which one wall has a fireplace behind it, you immediately notice how warm the wall is without coming anywhere near it.

        Considering that the "walls" in space are the 2.73K cosmic microwave background radiation, and that a person's temperature is more like 300K, you would radiate 10^8 times more energy than your receive. You'd freeze in a hurry.

        Now, if there's a star heating you from one side, this can partially make up the difference. You still get the one-side-super-hot and one-side-super-cold problem, then, like the surface of Earth's moon writ small.
        • by AKAImBatman (238306) * <akaimbatman.gmail@com> on Tuesday March 06 2007, @12:07PM (#18251236) Homepage Journal

          Since theres no air convection taking heat away from your body and any sweat would immediately vapourise as it came out your pores so it wouldn't have a chance to spread over your skin and cool you.

          When you sweat, the fluids come from inside your body. Since they're already heated, they will carry away some of the heat when they vaporize. So you'd probably die of other causes long before you overheated.

          In the Space Shuttle, however, the bay doors are opened for heat rejection when in flight. Unlike the "cold" problem we see in Star Trek whenever they lose power (e.g. TNG: Booby Trap), they're far more likely to overheat due to the heat rejection systems being inoperable. (Presumably, a ship like the Enterprise would have a circulatory system that would pump heat from the inside of the ship to the outer skin, where it would be rejected as black body radiation.)
          • by Spazmania (174582) on Tuesday March 06 2007, @12:43PM (#18251882) Homepage
            Actually, sweat works because the evaporation process is endothermic. When water turns from liquid to gas it consumes heat. That's why you can cool down to 98.6F even when its 105F outside. That's also why a room with a "cool mist" humidifier consisting of a fan and a sponge-like filter will cool down several degrees.
        • by soft_guy (534437) on Tuesday March 06 2007, @01:18PM (#18252482)

          I often wondered whether if you were in a vacuum you might even overheat?
          I'd be more worried about not being able to breathe.
    • by xtracto (837672) on Tuesday March 06 2007, @11:59AM (#18251122) Journal
      Something which is not really "physics" but I found interesting is about Suppressors:

      1. They are called Sound Suppressors [wikipedia.org]not "silencers". They do not "silence" the sound just diminish it.
      2. They do not really suppress the sound the way movies put it (I am looking at you Mr. Bauer).

      Motion pictures have produced the common misconception that sound suppressors ("silencers") completely silence the weapon's sound, or reduce it to a quiet whistling sound, which is in most cases very far from the truth. In fact, the emergent noise can still be heard from a fairly large distance. The quiet whistling sound associated with silencers is more attributable to the noise made by air guns
      3. (And the most interesting for me) They are good just for a small number of shots (Yeah, again looking at you Mr. Bauer)

      Very effective suppressors either involve a large total suppressor volume, a moderately large volume plus many baffles, or wipes. It is possible to design a very small and compact suppressor with wipes which effectively silences a pistol; these suppressors have a lifetime of as few as 4-5 shots and typically no more than a few magazines of ammunition. Larger wipeless (baffle only) pistol or rifle suppressors may be nearly as effective for long lifetimes (hundreds or thousands of shots) but are relatively bulky, clumsy, and heavy.
    • by i_should_be_working (720372) on Tuesday March 06 2007, @12:32PM (#18251696)
      So, like you and the two responses above me, I was really skeptical of this "freezing in space" idea. I even told a student that a reference they had cited was wrong in claiming that you would freeze to death in the Sun's corona, the argument being that you wouldn't freeze for the same reason you wouldn't burn: no particles to transport heat.

      But I recently found out, from a colleague over beer, that loss of heat from blackbody radiation is actually much faster than I thought. In the old days, in non-cold places, some people (ancient Egyptions among others) would actually make ice, basically by letting water in a deep, dark place radiate it's heat away. Sure it took hours, and it had to be already pretty cold outside, but considering that the water was also being continually warmed by all the air around it, that's pretty impressive for "only" blackbody radiation.

      It's pretty easy to calculate heat loss. According to this [wikipedia.org], in our 293K atmosphere we lose 95W. In a 2.7K vaccuum this translates to 640W, due to us not getting any energy back from the atmosphere. With an average human body heat capacity of 3470 Joules per Kelvin per Kilo, a 70Kg person will drop to the freezing point from 305K in less than 3 and a half hours.

      Ok, so that's pretty slow. Damn those movies suck.
    • by swschrad (312009) on Tuesday March 06 2007, @11:56AM (#18251078) Homepage Journal
      radium paint didn't glow because radium did... not in that concentration, or in those colors. the radium was mixed into a heavy coat of standard enamel with a whole bunch of phosphorescent pigments, which glowed.

      until they burned out. old WWII radio dial markings from military gear have a lot of brown markings. they are radium paint with the phosphors all burnt out atomically, like a ghost image on a burned-in computer screen or monitor screen on an ATM. still radioactive and dangerous if ingested.

      radium, polonium, radiocobalt, and other strong alpha emitters will emit a Czerinkon glow of blue when in the presence of hydrogen or water, which may be what you are thinking of. the blue glow is that of ionized hydrogen from the alpha hits, however, and should be thought of as a form of phosphorescence.
    • by Rob the Bold (788862) on Tuesday March 06 2007, @11:56AM (#18251080)

      If I punch a punching bag, the bag moves but I don't. That is because my fist has the energy which transfers to the bag. I don't go flying backwards as the article suggests.

      Friction, dude. Try the experiment again on roller skates.

      • by joto (134244) on Tuesday March 06 2007, @01:14PM (#18252406)
        Nope. It's because:
        1. The punching bag is much lighter than you, so the force in the punch will move it forward much faster than it will move you backwards.
          • In a correctly done punch you will start the movement at your feet and accelerate your hips/body as well as your fist toward the target. This means that instead of you being moved backwards by the impact, the impact will stop (some of) your forward movement.
          • In an incorrectly done punch, it will be only your fist and the punching ball that collides (not you or your body weight behind it). This is insufficient force/momentum to move your body in any significant way (or do any damage to an opponent in a fight)