Coriolis Effect--Science or Superstition?

[Pyrotex]

Originally Posted by cnewtongifford

...Coriolis taught otherwise--that while these greater accelerations through space are unnoticeable, the smallest one (Earth's rotation) is noticeable (part of the physics of the terrestrial experience). I have never found any explanation--from Coriolis or anyone since--for that apparent contradiction...

CNT,
perhaps...(perhaps)... the basic difficulty here is the distinction between an accelleration and a velocity.
An accelleration is, at its simplest, a change in velocity. If you are at one million MPH and stay at one million MPH, there is no change and no accelleration. If you are at one million MPH and change to 0.7 million MPH (or to 1.3 million MPH) in, say, one week, then there IS a change and there is an accelleration. In this case there would be an accelleration of either -0.3 or +0.3 million MPH / week.

Okay, another case and we're done. Velocity can change in another way, because velocity is a "vector"--it has both magnitude (speed) and direction. I you are at one thousand MPH due "east" (relative to galactic coordinates or the distant stars) and twelve hours later, you are at one thousand MPH due "west" (relative to same background) then your velocity has changed and there was an accelleration -- even though your speed never changed (1,000 MPH).

And this is exactly what happens on the Earth's surface. Every 12 hours, your velocity vector points in the opposite direction as you whirl around attached to a fixed point on the Earth's surface. That requires an accelleration. And an accelleration requires a force. F=ma. Where F is the Force and a is the Accelleration.

Our wandering through the universe may include huge velocities but these are velocities that either do not change, or change only over tens of millions of years. Nobody feels just "speed". You only feel accelleration. Any body at rest or in constant motion tends to stay at rest or in that same constant motion. [Newton]. If your motion stays the same, there is no accelleration, and therefore no Force.

But if you are whirling around in a circle, your velocity vector is changing all the time. That requires an accelleration. That requires a force. And it ain't gravity.

[Zythryn]

I have been lurking a bit and following this fascinating thread.

Pyrotex, I think you hit the nail right on the head and I am hoping that helps cnew with his question.

Cnew, if that still doesn't help, try this:

You mentioned that you didn't see why the rotational speed would have an effect that could overcome the affects of the solar system's speed or the galaxy's.

As Pyro explained above, the rotation of the earth actually has a greater acceleration due to the change in direction. Thus you get a greater local effect.

To test this, fill a glass with water. Stir it with a straw (or anything handy). The local rotaion of the water easily overcomes the affect of the speed of the solar system with very little energy (far less than the energy in the movement of the solar system).

Thanks to everyone for a wonderful discussion!

[cnewtongifford]

Originally Posted by TheBigDog

The moment that the rocket lifts off of the pad it is no longer connected to the earth, and is free of the earth's inertia.
Bill

Bill: I commend you for the effort you have obviously put into this topic. Please hold the thought quoted just above as we go through a seemungly simple analogy:

Let's say we are on a train, which is on straight and level tracks, moving at a constant speed. Let's go to the dining car and commandeer a table for an experiment. We take a large paper target, with a bull's eye surrounded by concentric citcles, and paste it to the table. We position a ping pong ball directly over the bull's eye and drop it. It falls, hits the target, then bounces a few times until it comes to rest.

How would you predict the ping pong ball to behave, in relation to the bull's eye? The answer may be simple--or as complex as the whole Coriolis body of work.

(I am behind in my duties here as resident provocateur--will catch up and review other recent posts as time permits)
Thanks again, CNG

[TheBigDog]

Originally Posted by cnewtongifford

Bill: I commend you for the effort you have obviously put into this topic. Please hold the thought quoted just above as we go through a seemungly simple analogy:

Let's say we are on a train, which is on straight and level tracks, moving at a constant speed. Let's go to the dining car and commandeer a table for an experiment. We take a large paper target, with a bull's eye surrounded by concentric citcles, and paste it to the table. We position a ping pong ball directly over the bull's eye and drop it. It falls, hits the target, then bounces a few times until it comes to rest.

How would you predict the ping pong ball to behave, in relation to the bull's eye? The answer may be simple--or as complex as the whole Coriolis body of work.

(I am behind in my duties here as resident provocateur--will catch up and review other recent posts as time permits)
Thanks again, CNG

CNG, you drove me bust out a pen and paper and do this long hand during an exceptionally boring meeting today. Here is the answer.

If we remove such things as imperfections in the tabletop, paper and ping pong ball, then we can make some assumptions about what it is possible to observe. The ball will drop, hit the bulls-eye, bounce on the bulls-eye, and come to rest on the bulls-eye. The reason for this is that we have eliminated unpredictable elements from the equation and only measured based upon what we can observe without instruments.

The reality is that what we observe and what happens are not the same thing. Assuming the earth is 8000 miles in diameter, and that the ball is dropped from a height of 1 foot, at the time of the ball's release it is traveliing around the earth on a slighly bigger circle than the target, but is making one revolution in the same amount of time. This is regardless of the speed of the train. Because the ball is travelling further in the same amount of time it is moving faster than the table top. How much? 0.0000047% at the equator. That is not very much. Far less than we could easily measure to prove that it existed.

Try this for an example. You and I meet at a high school track. I get in the inside lane, and you get in the lane next to me. We begin to walk around the track taking the same sized steps at the same pace. Who finishes a lap first? That is why things above the top of a tower is moving faster than the bottom of the same tower. Not much faster, but it is there. The rigidity of the building and the minute force in play makes in a non issue for the building, but the fact is still there even if we don't see it.

Here are a couple of things that would make your example work...

1. The earth is flat
2. The experiment is done at the point of the earth's axis with the train parked
3. The train is moving in the opposite direction of the earth's rotation at the same speed as the earth's rotation

Give me another example to work with to prove your point. In the early posts on this thread you state that you want someone to disprove your theory without using math. I would challenge you to show me proof of your theory with math.

Bill

[cnewtongifford]

Originally Posted by TheBigDog

The ball will drop, hit the bulls-eye, bounce on the bulls-eye, and come to rest on the bulls-eye.
Give me another example to work with to prove your point. Bill

Bill: If they find out you were actually thinking during a meeting, you'll be in serious trouble.

I thought I was being clever to NOT answer my own question. I was hoping to get you to work out how the bouncing ping pong ball will decelerate relative to the bulls eye. This is directly material to Coriolis-ism.

Encyclopedias usually use a rotating disk to illustrate how a "shot" fired from C toward P actually hits P' , creating the illusion, from the disk's point of view, that the trajectory has curved. True enough. My contention is that this disk illustration is non-analogous to Earth.

If you could put a saddle on that "shot" going out from the center of that disk, and go for a ride, you could do some detective work. If you looked 90 degrees to the side, facing the direction of rotation, you would see that the
disk surface was pulling away from you. Which could be explained in terms of motive force. Whatever force continues to provide the disk's rotation has ceased to provide the "round's" rotation--as of the moment it was fired.

Your encyclopedia will begin trying to connect that disk with our Earth with a paragraph like this:
'In accordance with fundamental definitions a curved motion
represents an acceleration (a) and an acceleration is the result of the
action of a force (f) which is proportional to the mass (m) of the
object and the speed (v) with which it is moving.'

But wait: this 'force (f)' is a misnomer. What is really happening on that 'disk' is the cutting off of force. That illustration confuses the force which moves the disk and the disk itself. Which is one big reason I think a train or rocket is a heckuva lot more scientific example. If the caboose of a moving train is cut loose, it will begin to decelerate, relative to the locomotive. And when those spent fuel tanks are jettisoned from an
ascending rocket, they begin to decelerate, relative to the rocket. There's a principle there, which applies to all terrestrial transport: Delta force causes delta travel.

So when you drop that ping pong ball it is like cutting the caboose loose. It ceases, briefly, to receive power via the train, and will experience a slight lag, relative to the continuously powered train. There will be a change between the train's momentum and the ping pong ball. The ping pong ball will move away from the bull's eye, exactly opposite the direction of the train.

And from there, it will be apparent that you don't need to hypothesize about 90 mile artillery shots. No. sir, all kinds of local experiments would be available to test whether that rotating disk in the encyclopedias is--or is not-- analogous to earth. One that appeals to me is to take 100 or so basketballs up on a big boom near the ceiling of a basketball arena and drop them directly over a mark on the floor. If more basketballs come to rest West of the mark than anywhere else, you'd have support for Coriolis-ism. But if they come to rest randomly--favoring no direction relative to the target--then they would directly call into question the comparability of that encyclopedia disk to terrestrial transportation.

Coriolis-ism requires the belief that--in terrestrial transportation--an airborn object has lost contact with Earth. But it isn't having your toes in the dirt that makes you part of Earth--it is being within Earth's gravitational field. There is absolutely no difference to that gravitational field whether you are a bird or a turtle. If you are inside the gravitational field, you are operating on terrestrial laws. Including the one that says there are no free rides. All relocation within that gravitational field has to be accounted for in terms of transmission of energy. (A cut-loose terrestrial caboose tends to lose).

So Coriolis went off the rails before he ever got into his math--by assuming the sameness of terrestrial rotating disks--and Earth. In Coriolis-ism, to question that premise is heresy, blasphemy, not allowed.

I apologize if I seem unsportsmanlike in this discussion. But this isn't like Law, where all you need to understand is the accepted, established precedent (right and wrong has nothing to do with anything). This is about a physical principle, basic to our world, and it's a black and white issue. Have you seen any sign that our world is like a rotating disk?

Do you know anybody with access to a basketball gym?

Thanks again, CNG

[TheBigDog]

Well, at least you acknowledge that I can and do think! But then you quote me so out of context that I wonder if you read what I wrote?

Let us assume that you and I are standing in yard together. We are each wearing a watch, and we st them to exactly the same time. We have a third watch that we tape to a ball. It is also set to the same time. We then walk to opposite ends of the yard and begin to throw the ball back and forth to each other. The ball is moving much faster than you and I. You and I are moving at the same speed. After throwing the ball back and forth for awhile, we stop and regroup. Comparing the three watches we see that they are all still reading exactly the same time. Satisfactory? Yes, for all normal purposes the three watches are still exactly in sync. But the watch that was being thrown back and forth actually kept time slower because of its increased velocity. This is an incontrovertible fact. But the amount of time difference is so incredibly small that we cannot see it. It is so small that in our every day lives it is completely irrelevant.

The same is typically true of the effects of the earth's rotation. It is there. That is (except for an elite few ) an incontrovertible fact. And this is not the only thing that falls into the category of "too small to notice". If I take a 500,000 ton weight to one side of the earth, and a 5 ounce weight to the other side of the earth, and drop them both from the same height at the same time, will they both his the ground at the same time? Observably, yes. Actually - no. Not only are both weights being attracted by the gravity of the earth, but the earth is being attracted by the gravity of both weights. The earth should actually fall toward the heavy weight faster than is does toward the light weight. Does this does not mean hat anyone would ever actually need to account for the difference because it is so imperceptibly small that it is totally inconsequential.

Close to the surface of the earth, with the random forces and general resistance of the atmosphere it is extremely difficult to demonstrate the effects of the rotation of the earth. Your experiment with the basketballs will prove nothing due the to variables in the experiment that you cannot control, and the incredibly small effect of the rotation of the earth on a body falling from even a few hundred feet. But just because you cannot detect it through normal observation does not mean that it is not there. That is why the pendulums work so well. They let a body essentially fall for a long period of time without ever landing. The high mass of the pendulum insures that it gets little interference from the atmosphere, and the long swing gives it a high inertia. Even with that you cannot see the rotation of the earth with just one or two swings of the pendulum. You need to watch it over a period of time. That experiment shows me the effects of the rotation of the earth. - that the earth is like a rotating disk.

Bill

[Erasmus00]

Originally Posted by cnewtongifford

I was hoping to get you to work out how the bouncing ping pong ball will decelerate relative to the bulls eye.

It won't. You claim that the train is moving at a constant speed on level tracks. In this ideal situation, the ball will land directly on the bullseye, bounce and keep bouncing on the bullseye. An object in motion remains in motion at a constant velocity with no need for a force to accelerate it. Its Newton's first law.

But wait: this 'force (f)' is a misnomer. What is really happening on that 'disk' is the cutting off of force.

You are right about that. The coriolis "force" isn't a real force, but an apparent one. It comes about because we use Earth (a non inertial frame) as our reference.

If the caboose of a moving train is cut loose, it will begin to decelerate, relative to the locomotive.

Only because of friction. The more straight and level your tracks and the better the axle is greased, the slower the caboose moves away. In an ideal situation, it would stay right with the train.

There's a principle there, which applies to all terrestrial transport: Delta force causes delta travel.

This isn't true. Newton's 2nd law, Force = d p/d t, where p is momentum and t is time. More often, Force = m*a = m d v/d t, where v is velocity and m is mass.

Rearranging we see that F dt = m dv. Brief forces cause small velocity changes, not small position changes. You are going back to the mechanics of Aristotle.

So when you drop that ping pong ball it is like cutting the caboose loose. It ceases, briefly, to receive power via the train, and will experience a slight lag, relative to the continuously powered train.

First, on ideal tracks with an ideal train you wouldn't have to continuously power your train. Obviously, this isn't the case. Even keeping that in mind, if we can keep the train from accelerating during our experiment, the ball will fall on the bullseye. The air inside the train is moving with the train, as is everything else inside. There is no friction/resistance to push the ball back relative to the train, as there is in your caboose example.

If you're ever on an airplane, wait untill its levelled out and try throwing a coin up. If on a relatively slow train, the coin would move back slowly, on a much faster airplane, the coin should quite quickly move back. You'll find instead it goes more or less straight up and back down.

One that appeals to me is to take 100 or so basketballs up on a big boom near the ceiling of a basketball arena and drop them directly over a mark on the floor. If more basketballs come to rest West of the mark than anywhere else, you'd have support for Coriolis-ism.

This experiment is pretty flawed. The balls can take all sorts of random bounches, and will interact with each other. Odds are, most of the time they'll all roll away.

Try the following: build a cart and two tracks, one long and straight and one a nice smooth circle. The cart should be set up so you can launch it at the same speed everytime, (perhaps by having it compress a spring to a fixed length and then have the spring launch it). It should also have a built in launcher for a small metal ball that works on a short timer.

Now, first run the cart on the straight track, nice and level. Have the ball launch sometime during the run. You'll find that if your tracks are reasonably level, the ball will land right back in the cart.

Now, use the circular track. This time you'll find the ball won't land back in the cart.

By playing with your tracks and different angles, maybe building some ramps to test gravitational effects, you can learn a great deal of physics.

But it isn't having your toes in the dirt that makes you part of Earth--it is being within Earth's gravitational field. There is absolutely no difference to that gravitational field whether you are a bird or a turtle.

That simply isn't true. When you are making contact with the Earth, there is a great deal of friction between you and the surface. This drives you around in your circular motion. As soon as you aren't touching the Earth, that friction isn't there.
-Will

[Qfwfq]

Erasmus, you're so often in the habit of saying "That simply isn't true." and the likes, but when someone is arguing against accepted facts there's not much point in saying that kind of thing.

Originally Posted by cnewtongifford

My contention is that this disk illustration is non-analogous to Earth.

If you understand the disk illustration, on what grounds do you claim the lack of analogy? I think that in your case you can only turn to experiment, as long as you do it in such a way that it could falsify the opinions about falling bodies deviating eastward, cyclones and anticyclones or oceanic currents, Foucault's pendulum....

[cnewtongifford]

[QUOTE=Qfwfq] on what grounds do you claim the lack of analogy? QUOTE]

Qf: 1) The rules of motion on the disk are essentially different from the rules of motion 'on' Earth's surface (only on the disk is thereany material difference between angular vs linear velocity, expressed in physical momentum variances)
2) The math of the Coriolis formula is flawed (it fails to include the inarguable principle that 'a terrestrial cut-loose caboose tends to lose'--i.e: that the first component of Resistance to terrestrial motion is the mass of the object to be moved, which is distinct from everything commonly classed as friction).

The bouncing ball on a moving terrestrial train was the simplest illustration I could come up with to try and shed some light on this basic truth. It has now been over a week since anyone has spoken up. There have been 2 purported "rebuttals', no sign that even one person out there, anywhere in the world, understands that bouncing ball on the train.

So I have failed. I give up. This thread seems to have been killed. There is a difference in assembling around a campfire and discussing something--and assembling around a campfire and peeing on the fire.

Good night and good luck. CNG

[Qfwfq]

Originally Posted by cnewtongifford

The rules of motion on the disk are essentially different from the rules of motion 'on' Earth's surface (only on the disk is thereany material difference between angular vs linear velocity, expressed in physical momentum variances)

The difference is in the sine of latitude. If you move toward the equator you are increasing your distance from the axis of rotation but this increase, for an element of distance ds along the meridian, is equal to ds times the sine of latitude.

Originally Posted by cnewtongifford

The math of the Coriolis formula is flawed (it fails to include the inarguable principle that 'a terrestrial cut-loose caboose tends to lose'--i.e: that the first component of Resistance to terrestrial motion is the mass of the object to be moved, which is distinct from everything commonly classed as friction).

Well, if you like to believe that, good night and good luck. I just love the relief of the bladder after peeing on campfires. If you want to meditate upon the bouncing ball on a train, you might find it interesting to read Galileo's dialogue, he goes well into such matters.