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THURSDAY, OCTOBER 27, 2016
As I thought up this list, I came up with many many many more examples in my head of ones that were wrong. Many of which are due to Hollywood movies. So while this list may feature a lot from Hollywood, it's not restricted to that. It's really just a list of things that cheese me.

7. Sound in Space - The movie Armageddon. Man do they have it wrong. There is so much sound in that movie - in a movie that takes place in Space! Space. A Vacuum! No particles (unless you consider planets, asteroids, et. al as particles... big particles). Sound is the vibration of particles. Sound is not an electromagnetic force. It's a wave of particles colliding. In space, there are no particles to wave, to collide, nothing. And there is no sound. Thus the caption for Alien: "In Space No One Can Hear You Scream" In fact, that movie also has a lot of sound in it. To date, just about the only movie I've seen that honors the no-sound-in-space rule is 2001, by Kubrick. Only Kubrick could really pull silence off. And that's why 2001 is pretty inaccessible to many people. They need their sound.

6. Gravity on Earth - I'm going to be specific here about gravity on earth. By this I mean on the Earth's surface, and a few hundred feet above it. Movies get this wrong all the time - they have objects falling at different speeds, the best example being Spiderman who leaps upwards into the air, then arches his body in perfect form, and begins his rapid descent towards Mary Jane, who has been falling this entire time. Impressively, Spiderman catches up to her, and saves the day. Not in this world. I don't care if he's wearing a sleak, streamlined suit. Neither does physics. Objects fall at the same speed. Spiderman show-boating his jump into the air, and embellishing the heroic deed would have really just seen Mary Jane fall to her death...

5. Gravity at the Center of the Earth - I'm going to ignore the movie Core. That was pornography of physics. A more recent movie that really got my goat (thankfully I have many goats to be got), was Journey to the Center of the Earth. Than Brandon Frasier flick. I never saw it. I only saw the trailer. And the trailer was enough to tell me that there would be no science in this movie. What did I see? I saw a waterfall at the supposed center of the Earth. A waterfall? Sorry, but if you could - for a moment - assume that the center of the Earth was a hollow sphere - and not molten rock, completely hollow, then you would float around. Why? Because Gravity completely cancels itself out at the center of the Earth. Vector diagrams people. Center of the earth has no gravity. Nor is there a concept of direction. How can water even fall? That would assume there's a "down" at the center. There's no down. There's only symmetry. There's no up. There's only symmetry. There's physics, not some miserable attempt at a film.

4. Gravity as a general rule of thumb - People seem to change gravity as they see fit. Objects falling at different speeds - that's 6, gravity at the center of the earth, that's 5. But there's also the general misuse of gravity in many films. Like when Peter Parker punches Eddie Brock, and Eddie Brock flies accross the room in almost a straight line, and then starts an arc'd descent. Your eyes tell you that something looked weird about that. And it's because, frankly, your eyes know more about physics than the average Hollywood director.

3. Water But more specifically, water at high speeds - Apparently Hollywood spends little time in the massive olympic sized pools they have in their backyards. Or at least, they don't fall into their pools at the high speeds they have in their movies, where someone will fall a great height into a pool of water and survive. Or skin across the surface of the water, and survive. If you've ever done a bellyflop into a pool, you'll know how much it hurts. Now imagine doing that after falling from a cliff. Or a helicopter. Maybe you'll survive... but if you think you're about to get back up and go fight the Amazon rebels.... think again.

2. Quantum Mechanics - I'm not even going to get into it. But if you've seen it in a scifi movie, or read it in a scifi book, there's a 99% chance they got it wrong.

1. Evolution - Whether you consider yourself an evolutionist, or a creationist, Evolution as a theory is constantly used incorrectly. Plus it's argued against incorrectly. One common argument is that Hitler used evolution to justify the Holocaust... therefor, what? We should stop teaching evolution? To my knowledge, oil has also been the justification for some wars. As has religion. As has land. As has diamonds. Should we stop all these? Another argument against evolution is that of the watchmaker. Unfortunately, the watchmaker analogy has it completely wrong, and is wrought with so many fallacies in it, it cannot be taken seriously. And this notion changes what people think evolution really is.

I know I spent little time really explaining the theories that I'm arguing Hollywood and company often get wrong. But I'm not about to explain them. Those who care will look it up. Those who won't, will buy tickets to the next (Insert Film Genre Here) Movie
Comments

Alamir

Alamir

Point #5 doesn't mention that air-friction has a lot to do with what falls faster than others. If spiderman has a stream lined suit and MJ's skirt is helping her trap air (kind like how Princess floats in SuperMario2) then Spiderman can descend faster.
REPLIES: alishahnovin

alishahnovin

alishahnovin

Replying to Alamir:
It comes down to surface area, but I remember we even discussed that specific scene in one of my Physics courses... I mean, you need a huge skirt to really give a lot of drag for Spiderman to catch up. And they're falling from a building that isn't so tall. Drag really doesn't make much of a difference here. Plus, I may be wrong, but the way it's filmed it seems like Spiderman is going faster, while Mary Jame falls at a steady rate. So rather than her slowing down due to drag, he's actually speeding up.
REPLIES: Alamir

Alamir

Alamir

Replying to alishahnovin:
First let me make it clear that I barely remember the scene you're speaking of and that I just wanted to point out that you have to take into account air friction in your original post for the sake of showing you considered it, regardless whether Spiderman could save MJ.

But to your latter point, it makes sense for Spiderman to be going increasingly faster due to gravity's acceleration. So when you say "rather than her slowing down due to drag, he's actually speeding up" it's the other way around. He's speeding up, as he should (acceleration), by her going at the same rate of speed she's not accelerating 9.8 m/s/s and decelerating to the point of a constant speed (therefore creating drag).
REPLIES: alishahnovin

alishahnovin

alishahnovin

Replying to Alamir:
While you're right, you're not completely right. First to clarify, to say that all objects fall at the same speed on earth, means they are accelerating. While speed is strictly used for velocity, or better put the rate of change of some quantity, over time, when you talk about objects falling at the same speed, you are saying that the speed of their falling is the same, and since falling is displacement, it's a rate of change of a speed, over time - ie. acceleration.

So: All objects on earth fall at the same speed. Or differently put, they all accelerate towards the earth with the same acceleration.

With velocities, reference frames must be taken into consideration. For example, my moving towards you at constant speed X, while you stay still, is analogous to you moving to me at speed -X, and I stay put. They're the same thing.

With acceleration, however, the situation is different. If I accelerate towards you, and you stay put, this is entirely different than if you were to accelerate towards me, while I stay put. While you can construct a reference frame in which it seems like you are accelerating towards me, when in fact I am, the important distinction is that because acceleration is a Force over a mass, I am exerting a Force to move towards you, while you are not exerting any force at all. That's the difference with acceleration and reference frames. With velocities, there are no forces at play, and so the reference frames are the same.

Now, drag. Drag is a coefficient. A constant. You can increase the drag coefficient of an object, but the important point is that it is a static value that does not relate to mass, velocity, or acceleration. And more importantly, it's very difficult to come up with some really high drag coefficient in a dress. I hear Versace is working on one, but that's probably out of Mary Jane's budget.

Anyway, when I say that Spiderman is going increasingly faster, what I meant to say is that he is accelerating beyond the speed of gravity. In other words, he is exerting a force to move faster, to "fall" faster. It's the only way for him to catch up to Mary Jane, because there is in now way for her to have enough drag on her. It is like Spiderman has a jet pack on his back, which allows him to accelerate higher than 9.8m/s/s. And this is what I'm saying - this is what looks weird to the eye. The way the shot is, it is as though Spiderman has the force being exerted on him, to accelerate even more.

If he caught up to her purely due to drag - again, I reiterate how incredibly unlikely that would be - then what would occur is that she wouldn't be falling at 9.8m/s/s, just as he would. However, her drag coefficient would affect her own speed (she would have an additional force acting against her falling, a force SHE would feel, thus changing her acceleration - and because this is an accelerated reference frame, who is doing the moving is a very important factor. So if she was not accelerating at 9.8m/s/s, then it would appear that she was doing the additional accelerating. But it doesn't appear that way. It appears like he's doing the additional accelerating... it appears like the force is acting on him.

For the record:
http://www.youtube.com/watch?v=S_u03Nh7Uu8 (it's around 1:15)

One last clarifying point: F=m*a. The force due to gravity on earth is a known, and acts on objects in the same way. Mass is a constant for an object. The acceleration of both Spiderman and Mary Jane is expressed as: a = F/m. The force due to gravity, is F=G*mE*mO/r^2, where mE is the mass of the earth, r is the distance of an object from the earth. G is a constant, and mO is the mass of the object. So a=F/mO=(G*mE*mO/r^2)/m1=G*mE/r^2. So as you'll see, because the mass of the object drops out of the equation, this means that all objects fall towards the earth at: G * the mass of the earth * the distance of the object from the earth. There is no drag, there is no mass of the object, no factors that would make Mary Jane fall slower or faster than Spiderman.

The addition of drag changes the force equation to be like: F = m*a - b*v, where b is the drag coefficient, and v is the velocity of the object. So both objects are falling at: F = G*mE/r^2 - b1*v, and F = G*mE/r^2 - b2*v, where b1 and b2 are different drag coefficients.

While they both have drag coefficients, the important part in this case is that the falls are not long enough, nor is the difference in their drag coefficients large enough for Spiderman to catch up to Mary Jane. Maybe if they had jumped out of a plane...but not a building.

Alamir

Alamir

Wow that was a long answer. But all you had to say was: "When I say that Spiderman is going increasingly faster, what I meant to say is that he is accelerating beyond the speed of gravity." Yes, assuming that Spiderman beat gravity, then he'd be going faster than MJ. But I think the movie was trying to work off the idea that he simply reduced drag rather than boost his fall. Everything else that you wrote about drag not being sufficient I've already admitted to not remembering the scene too well and only wanted to point out that you should take it into account. Even if it's to point out that it's rendered negligent



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