9 Laws of Physics That Don't Apply in Hollywood

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..."

Comments

9 Bad Excuses for a Fluff Piece

[AKAImBatman]

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

Re:9 Bad Excuses for a Fluff Piece

[badasscat]

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.)

Re:Outerspace is Cold

[xtracto]

Something which is not really "physics" but I found interesting is about Suppressors:

1. They are called Sound Suppressors 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.

Wile E. Coyote

[kfstark]

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

[inviolet]

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.

the most famous example is not mentioned

[swschrad]

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?

Re:Middle C

[superpenguin]

The quasi-official frequency for middle C is, as the original poster mentioned, 261.6ish. The rub lies in the fact that the only really "official", or at least widely accepted, standard of concert pitch defines A (as 440Hz), not C. On an equal tempered instrument, as most pianos are tuned, C will then end up at 261.6Hz. However, most other instruments allow on-the-fly adjusting of pitch (strings, winds, brass), which, at least in the hands of a capable performer, can result in being better in tune than an equal-tempered piano, as equal-temperment is a compromise that results in all intervals being slightly out of tune so that you can play in any key equally well (or equally poorly, depending on your point of view).

There's a handy little chart on Wikipedia for the frequencies of each note given equal temperment on A=440.

Now, for the historical aspect, take a look at that chart and consider that a common Baroque (17th and 18th centuries) tuning was A=413, which means about a half step flat to modern tuning. However, during the same period, it was not terribly uncommon to have a tuning as high as A=475 (over a half step sharp).

Even though we've more or less settled on A=440, the parent poster is correct that modern orchestras often get higher than that to create a brighter sound (although usually not much higher than A=445). This occasionally results in something of an arms race, although there's only so high you can go before the instruments start acting up. This arms race can also happen on a personal level. One of my cello teachers used to play in a European orchestra, where this sort of thing is somewhat more common, and he said that sometimes there would be players who would purposely tune sharp to the orchestra so they would stick out (generally speaking, if you're sharp to the ensemble, you sound bright, and if you're flat, you sound out of tune).

Interestingly enough, although I have not researched this, from anecdotal evidence it appears that string instruments tend to be a bit friendlier when tuned flat of A=440. I first noticed this when comparing two recordings of the Kodaly Suite for Solo Cello. One recording I had (Janos Starker) was more or less concert pitch, but the Yo-Yo Ma recording was about a half-step flat of A=440. I discussed this discrepancy with my teacher at the time and his response was that he had tried tuning his cello like that for solo work, and found it to be "looser" and more responsive and forgiving. Because string instruments behave better when they're kept consistently in tune to one standard, and because I do a lot of orchestral playing, I haven't experimented with this much, but I have noticed times when both my cello and my bass felt better, and then later realized that they'd drifted flat (which happens if you only tune the instrument to itself for a while).

All that to say that while A tends to drift higher and higher if left unchecked, we might be better off if we actually went flat of concert pitch.

Oh yeah, and I find C=256 very handy for back-of-the-napkin calculations, since it means easy powers of two for each octave.

/musician rambling

Re:Been there, done that.

[99BottlesOfBeerInMyF]

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.