BS - Science Question for Amos or Wolfgang

Subject: RE: BS - Science Question for Amos or Wolfgang
From: Bagpuss
Date: 27 Mar 01 - 09:27 AM

Came in too late to look smart and answer the question, but I do have a bit extra info. Tourists visiting places on the equator will often be persuaded to part with money by locals claiming to show the coriolis effect on water going down plug-holes. They show the water going different ways depending on which side of the equator they are standing. They actually produce the effect by the way they fill the bowl with water and the touristsfall for it.

However I don't begrudge an entertaining con-man, so don't blow his cover if you are ever there.

Bagpuss

Subject: RE: BS - Science Question for Amos or Wolfgang
From: GUEST,Bruce O.
Date: 26 Mar 01 - 04:34 PM

Rana, W. L mentioned above is retired, but back to work today at NIST. He had dinner with Ian Mills at Reading (and B. Cresswell-former Mills grad student at Cambridge) late last week on his way back from France. A. Robiette still in computers, but now at Warick (Warwick).

Subject: RE: BS - Science Question for Amos or Wolfgang
From: GUEST,Bruce O.
Date: 14 Mar 01 - 04:45 PM

And Irish wakes. They're so happy that the deceased gets to go to a spaced fixed coordinate system so he can see what that world he came from really looks like.

I started out yesterday to give acceleration equations in spaced fixed and earth rotating axis systems, but couldn't figure out how to get Greek letters in HTML. At any rate the equations are in a lot of physic books (mechanics section), but mostly on grad. student level.

Subject: RE: BS - Science Question for Amos or Wolfgang
From: Murray MacLeod
Date: 14 Mar 01 - 04:36 PM

Bruce, that would only be true if the room were spinning too. But that only happens very late on Saturday nights.

mURRAY

Subject: RE: BS - Science Question for Amos or Wolfgang
From: GUEST,Bruce O.
Date: 14 Mar 01 - 04:28 PM

Seeing is believing isn't always correct. Forces that depend on rotation make scientific optical illusions, because we on earth are doing some or all of the rotating. Going back to the water down the drain. We see all around us except the water as standing still. The water in bulk, because of the sink walls, gets rotated, too, by the rotation of the earth. Gravity is pulling it down (toward gravational center of the earth). But the water isn't doing all that much rotating in a spaced fixed Cartesian axis system (where physical laws hold); it's primarily going down, otherwise it's us rotating that makes the nearly stationary water (in space fixed coordinates) look like it's doing the rotating. [I hope I got that about right]

Subject: RE: BS - Science Question for Amos or Wolfgang
From: MMario
Date: 14 Mar 01 - 04:17 PM

it's the d*mned butterflies.

Subject: RE: BS - Science Question for Amos or Wolfgang
From: Murray MacLeod
Date: 14 Mar 01 - 04:16 PM

I am impressed aa well, believe me. But I still wonder how come with all this amazing body of scientific knowledege plus multi million dollar super-computers they still can never get the friggin' weather forecasts right.

Murray

Subject: RE: BS - Science Question for Amos or Wolfgang
From: Bert
Date: 14 Mar 01 - 04:15 PM

Oh the question was simple enough. It's the answer that's bloody complicated.

Subject: RE: BS - Science Question for Amos or Wolfgang
From: Little Hawk
Date: 14 Mar 01 - 04:03 PM

Amazing what happens when you ask a simple question isn't it? I'm impressed.

- LH

Subject: RE: BS - Science Question for Amos or Wolfgang
From: GUEST,Bruce O.
Date: 14 Mar 01 - 03:04 PM

I don't know what to think about the accounts of storms, hurricanes, and such above. It's well beyond me to try modeling such. But note that rotation causes Coriolis force, Coriolis force doesn't cause rotation. I also suspect that turbulance wipes out any observable Coliolis effects.

Subject: RE: BS - Science Question for Amos or Wolfgang
From: GUEST,Bruce O.
Date: 14 Mar 01 - 11:25 AM

I didn't alway find time. I had to give folk music up for up to 5 years at a time to learn (afterhours study) new technology when we went from plane grating spectrometers to gaseous lasers, then to tuneable diode lasers, then to Fourier transform spectrometers.

Subject: RE: BS - Science Question for Amos or Wolfgang
From: GUEST,Rana
Date: 14 Mar 01 - 11:12 AM

Noreen,

'Fraid I'm the only one on our side (though a friend on the side did work with me for a while). On a work related search once I did come across someone from Bristol U. who did Morris. Back in B'Ham once came across the Jockeymem Morris - half the side had Ph.D's in Chemistry - must be the solvents we inhaled as undergrads!

Bruce: Couldn't find your web link on mudcat, however a search on google for CH3D worked - impressive CV! Liked your folk music links - how did you find time!

Anyway, sorry to the rest of the group for the thread creep - been fun, however, so I hope you others don't mind.

Cheers Rana

Subject: RE: BS - Science Question for Amos or Wolfgang
From: GUEST,Bruce O.
Date: 14 Mar 01 - 10:54 AM

One time Ian got a new one (for night flying) that not only spun, it had about 8 little lights on it that would blink. I know Ian far better than I know Alan, and have had many long conversations with him over the years, some in my office, others at symposia.

Subject: RE: BS - Science Question for Amos or Wolfgang
From: Noreen
Date: 14 Mar 01 - 10:13 AM

Fascinating! Rana, I've heard about a morris dancing side comprising leather-clad bikers, and an accountants' morris side, but not yet a side of X-ray spectroscopists...!

Subject: RE: BS - Science Question for Amos or Wolfgang
From: GUEST,Rana
Date: 14 Mar 01 - 08:52 AM

Hi Bruce,

Yes - I had Ian Mills for several courses (he was the famous name I hinted above) - great lecturer (though we were always waiting for his bow tie to start spinning around) - if I stayed (or returned) to Reading he or AR would have been who I would have considered - I did a final year project with AR. The names you mentioned, I cannot recall.

Not returning, however, I proceeded into X-ray photoelectron spectroscopy of simple gas molecules (U. of Alberta) and then innershell electron energy loss spectroscopy of simple gas molecules (UBC). Practicalities reared its ugly head and so I suppose I'm now a surface type - XPS and in a few months time of Flight secondary ion mass spec. (we just ordered a (US)$1 million machine! That, with the Flying Cloud (and Morris dancing)tend to keep me fairly busy.

Cheers Rana

Subject: RE: BS - Science Question for Amos or Wolfgang
From: GUEST,Bruce O.
Date: 13 Mar 01 - 11:28 PM

Rana, yes. Know Ian Mills? This is supposed to be a folk list, it just that that subject got lost a couple of years ago. I learned my ray tansfer optics from electon spectroscopists before I found it in optics books, and if things work out right, I'll be using it again very soon. [Rectangular R-theta diagrams and such, but optical elements instead of electomagnetic fields] I'm going to be back into designing long path absorption cell of very low loss for a high resolution FTS IR spectrometer (maybe tomorrow, didn't get it all settled today, working with at least 3 spectroscopists that know Alan.) (My publications list is on my website-Mudcat's Links). I never had a paper with Alan. He was the 2nd to try to fit my CH3D data. I think I know where I can break the secular determinant near the middle now, so we only have to fit about 12 vibrational states at a time.

Early 70's? Did you run across two on sabbatical, Art Maki, or Walt Laferty. I forget when Jim Watson left Reading. I was the only one of my group that didn't do a sabbatical at Reading.

Subject: RE: BS - Science Question for Amos or Wolfgang
From: Amos
Date: 13 Mar 01 - 11:12 PM

That's the beauty of the 'Cat, Rana -- it goes anywhere and everywhere and always ends up with "what are we doing on a folk list?". Some of the best folks on earth ask themselves that question here, with surprising regularity.

Subject: RE: BS - Science Question for Amos or Wolfgang
From: GUEST,Rana
Date: 13 Mar 01 - 11:01 PM

Bruce O.

In one of your early posts on this thread you mentioned A.R. at Oxford - would this be Alan Robiette? I had him as a lecturer at Reading U. in the early 70's. I believe he moved on and got involved in computing more. I know that he and major name at Reading almost got me interested in vibrational spectroscopy for grad work, however, I ended up in electron spectroscopy - now how come this thread ended up in a folk list?

Cheers Rana

Subject: RE: BS - Science Question for Amos or Wolfgang
From: wysiwyg
Date: 13 Mar 01 - 07:39 PM

So... Coriolis is one of THOSE things! I used to say to my teen stepson Mike, when he would rant hor hours about what he knew HAD to be SO-- from my vast store of life expereince, I would say, "Yes, that is true in scinece, but not in life." Where a thing can be so, according to known theory, but for some reason the models of it in real life do not act as predicted. (Missing data, etc.) Poor Mike would try to get everyone around him to act like he thought they must, but then he'd find real life was a lot messier than he'd allowed for.

Pete-- no... I don't think so! Discuss? Not quite like wondering... I wouldnlt join the discussion group in GHeaven, but I would ciurl up on a blanket to muse with frinds about everything.

Cello proved too small. I kept standing up to reach around to bow, and was informed I would need a bass fiddle. It may have been that some female anatomy in the way, which is currently somewhat affected by gravity, may permit cello playing in the relatively near future, as gravity continues to exert its effect. Also my wrist was very angry with me for the bowing, although I did get some lovely sounds. So I will think about wrist exercises.... don't really want to tote a bass. Maybe the wrist strengthening and gravity effect will coincide and pay off for a few years of playing time if I watch closely!

BUT, the cello player and my fiddling husband took me up on my offer to add autoharp to the mix on the Jennings piece they had planned as a duet. You see, the cello was only at the church, available for me to try out, because of their rehearsal. I gained a new jamming buddy and she gained a new rhythm section, and my husband gained an enhanced jam grouping to support his work on the Fiddler's Fakebook. I was opportunistic, see; wondering seems to make lots of room for that.

~S~

Subject: RE: BS - Science Question for Amos or Wolfgang
From: GUEST,Bruce O.
Date: 13 Mar 01 - 07:11 PM

I guess we can consider Coriolis force as real, since we consider centrifugal force real. The both depend on rotational velocity, and when that goes to zero both forces vanish.

Subject: RE: BS - Science Question for Amos or Wolfgang
From: Scotsbard
Date: 13 Mar 01 - 04:03 PM

Coriolis "accelerations" ...

... pausing dramatically to lay a sheaf of quantum-mechanical probabilities on the classical tombstones of centrifugal and centripital forces ...

... cause the typical rotation of hurricanes and tornados (tornadoes? *L* ) in the each hemispere, but by slightly different mechanisms:

As pointed out above, when air flows towards the equator, the surface of the earth is moving more rapidly towards the east, which shifts the apparent direction of movement towards the west. The opposite is true for winds blowing away from the equator. When dealing with large areas of low pressure (since air generally moves towards areas of low pressure, and leaving discussion of how the low pressure got there in the first place for some other time), the air coming from closer to the equator spirals around the eastern side, and the air coming form farther from the equator spirals around the western side. This causes the rest of the air to follow suit and produces the classic spiral of a hurricane, but is also true for winds in general, though usually on a much less dramatic scale.

The direction of tornado winds is usually triggered by a similar overall pattern around pressures, but with the addition of significant vertical air flow. The cold air dropping through the center of a storm and warm air rising along its front change their distance from earth's aixs and equator, combining coriolis and turbulence effects to make a three-dimensional eddy. The same direction of spiral is initiated, but on a much smaller scale and with much stronger winds.

~S~

Subject: RE: BS - Science Question for Amos or Wolfgang
From: GUEST,Bruce O.
Date: 13 Mar 01 - 01:49 PM

Nothing like a pin in the buttocks to get a wonderer off his fanny and start doing something that might prove usefull. Thrown into something new, it often takes some thrashing around to get the problem defined, and something vaguely akin to wondering is lining up various options for tackling the problem, and doing a basic cost/benefits analysis to find a good way to go (but that quite often doesn't work out the way you thought it would, and figuring out why gives you another problem to work on).

Wolfgang slightly underestimated the deflection caused by Coriolis force on a projectile, but time of flight (from projectile speed) and distance and direction of shot have considerable influence, so therre are circumstances where he could be right on.

A master stratagist would have manouvered the enemy to about 10 km north of the equator and then gone 10 km south of it to fire off, in order to cancel the Coriolis deflection in the two hemispheres.

Subject: RE: BS - Science Question for Amos or Wolfgang
From: GUEST,Pete Peterson at work
Date: 13 Mar 01 - 09:50 AM

Coriolis force isn't real? Another myth down the tubes! BUT--
Consider a really big hurricane, one extending between latitude 30 and latitude 60 N. The earth rotates about 1000 miles/hour at the equator (spins once in 24 hours and it's about 24000 miles around, right?) so at lat 30 the air is moving at 1000 MPH cos 30 degrees = 866 miles/hour and at latitude 60, it's moving at 1000 MPH cos 60 degrees = 500 MPH. The difference in velocity between the south and north end of the storm is what makes the "Coriolis force". . . did I miss something? I'm sure I have.
WYSIWYG. . .good luck with the cello! Are you sure you aren't a closet Unitarian? Remember the old joke: where would you rather bed-- in Heaven or in a discussion about Heaven? (and all the UUs went into the discussion group) . . . actually Browning said it better than I "ah, that a man's reach should exceed his grasp, or what's a Heaven for?"

Subject: RE: BS - Science Question for Amos or Wolfgang
From: wysiwyg
Date: 13 Mar 01 - 09:16 AM

Bruce, yes. I know this, not in science, but in other things.

I've been wondering though... would most people rather wonder about things, or know them? Which part of the process of discovering is of more interest-- the long time spent wondering about and coming at a thing from different angles, or the moment when it all falls into place? Or do you like them equally but differently? Or does this vary according to what sort of thing it is, or why you want to know... leaving aside the obvious like survival-level stuff or stuff attached to paychecks!

Would you rather know, or be finding out?

I have a date with a cello this morning. Will it turn out to be better to know that I can or cannot become a cello player, or will I prefer to have just wondered?

Will it have more impact on me to have wondered about God, or to get the answers?

Stuff like that.

Your turns.

OK if I turn your thread sideways, LH?

~S~

Subject: RE: BS - Science Question for Amos or Wolfgang
From: Wolfgang
Date: 13 Mar 01 - 07:55 AM

The second post had all the information necessary.
I only can add a story why it is sometimes necessary to know about Coriolis acceleration. I am less sure that it is true than I am about Coriolis acceleration itself.

In early WWI, a German fleet lost a sea battle to a British fleet in the South sea. The reason was supposedly that the Germans as relatively newcomers on the oceans did not take the variability of Coriolis acceleration into account. They still had set their long range shooting correction to the position of the North Sea. (On a shooting distance of 20 km, the 'drift' to one side can be 40m, so my recollection. Now if you are shooting in the South Sea and correct to the wrong direction you are off by 80m. That can be the difference between winning or loosing a battle. That's why you always should pay attention in school even in remote areas of physics.

Wolfgang

Subject: RE: BS - Science Question for Amos or Wolfgang
From: GUEST,Bruce O.
Date: 13 Mar 01 - 01:22 AM

There's nothing like that thrill you get when you're finally (often after years of work) certain that you've got something new that's worthwhile knowing and will make a real difference in some practical application that will benefit the world. Adrenaline doesn't come close. Writing it up for publication (a dreaded job) seem no real bother. Shows you how crazy it can make you.

Molecular spectroscopy now sooner got out of it's infancy than funding for research mostly dried up. The division I worked in was completely disbanded about 2 years ago. Researchers were sent off to new jobs (which they didn't know much about), or retired.

Subject: RE: BS - Science Question for Amos or Wolfgang
From: wysiwyg
Date: 13 Mar 01 - 01:11 AM

Vortices. I think. I USED to be blonde, but not anymore.

"Coriolis force is almost fictitious. Dang! Another thing they taught me in school down the damn drain! I'm all for science but I never got the update notice on that one-- all these years, I thought that was something we could count on. Crap!

Seriously, I find it amazing how science is so often presented nowadays in the schools-- all "knowledge" really-- as though everything that can be known is now definitively known, and always was known to be so. I remember science being taught by people in love with wondering and discovering, who could say with full pride and shared excitement, "This is what we think, this is what we are thinking about, this is what we hope to discover, this is the best we can figure it for now...." Made you want to discover some things yourself. Made you think maybe you COULD, if you kept your eyes open!

Now... kids don't just think they know everything; they think the books give them license to think so.

~S~

Subject: RE: BS - Science Question for Amos or Wolfgang
From: GUEST,Bruce O.
Date: 13 Mar 01 - 01:08 AM

Of course not. I didn't get started on this month until the third. I started thinking something might be a little off the previous day when my watch calendar gave me Feb. 30. How am I going to get Mar. 1 and 2 back? I need them.

Subject: RE: BS - Science Question for Amos or Wolfgang
From: CarolC
Date: 13 Mar 01 - 12:40 AM

Is it April 1st already?

Subject: RE: BS - Science Question for Amos or Wolfgang
From: GUEST,Bruce O.
Date: 12 Mar 01 - 11:56 PM

I'm not sure of that Mark. I took some dehydrated water on a camping trip once, and after I'd reconstituted it with H₂O, it was just as wet as the regular stuff.

Subject: RE: BS - Science Question for Amos or Wolfgang
From: GUEST,Bruce O.
Date: 12 Mar 01 - 11:47 PM

Herbert Goldstein, 'Classical Mechanics', says the the pendulum at the North pole and elsewhere on the earth's surface act qualitatively similar, but the details are a bit different and and are left to the reader (student) as an exercise. That exercise is the last (and undoubtably hardest) problem at the end of the chapter. I don't think I ever tackled it, and I have the student's edition of the book, without the answers to any problems. So work it out yourself, or go to www.bibliofind.com and try to get the instructor's edition with the answers (and check that the answer to problem 12, chapter 4 is there before you buy it).

Subject: RE: BS - Science Question for Amos or Wolfgang
From: Cap't Bob
Date: 12 Mar 01 - 11:00 PM

Another great mystery, in the who cares department, has to do with the movement of water up through the trunk of a tree. Some years ago I had the opportunity to observe the results of an experiment that a forestry class was doing concerning the movement of water through trees. They located a root, surrounded it with a contained of dye and after the dye was make its appearance in the leaves, they cut the tree down and cut it up into sections around two feet in length. The class discovered that the dye went up the tree in a spiral clockwise manner.

ALSO IN THE TREE DEPARTMENT: The bark of eastern white cedar trees is rather stringy. The next time you are in a cedar swamp check it out. The bark spirals in a clockwise manner. Now you know the rest of the story.

Cap't Bob

Subject: RE: BS - Science Question for Amos or Wolfgang
From: Mark Cohen
Date: 12 Mar 01 - 10:30 PM

Banjer, don't let these Mr. Science guys fool you with all their doubletalk. Water won't burn because it's wet. Dry it out, it'll burn like a house afire. Of course, there ain't no ash will burn....but that's another song.

Mark

Subject: RE: BS - Science Question for Amos or Wolfgang
From: Amos
Date: 12 Mar 01 - 09:45 PM

I thought I was, but I am always open to new perspectives!! :>) Anyway, the result of all them atoms jumping around like so many teenage bedfellows is a molecule of water, just like the ones you pay a buck a pint for when they put a fancy label on it!

ABruce, when I was a yopungster i liked to think I had slept with the best, but your preposition makes a more meaningful proposition! :>)

A

Subject: RE: BS - Science Question for Amos or Wolfgang
From: SINSULL
Date: 12 Mar 01 - 09:37 PM

And I thought that the water goes down the drain counter clockwise because my son dropped a penny down there. (It was clockwise previously). Live and learn.

Subject: RE: BS - Science Question for Amos or Wolfgang
From: GUEST,Bruce O.
Date: 12 Mar 01 - 09:22 PM

Amos was correct, atoms are the parts that make up molecules, but terminology can be confusing here because it's usually molecules of hydrogen (H2) that react with oxygen (O2) molecules to make water. It's actually a chain reaction if you break it into single steps, moving one atom at a time from one molecule to another, and sometimes bouncing another atom out.

Subject: RE: BS - Science Question for Amos or Wolfgang
From: ddw
Date: 12 Mar 01 - 09:09 PM

Amos — don't you mean molecules of oxygen and hydrogen? Not atoms? Tut tut.

david

Subject: RE: BS - Science Question for Amos or Wolfgang
From: GUEST,Bruce O.
Date: 12 Mar 01 - 09:00 PM

Not everyone and say they slept through the best.

Subject: RE: BS - Science Question for Amos or Wolfgang
From: GUEST,Bruce O.
Date: 12 Mar 01 - 08:53 PM

For the life of me, I can't think of what the difference is offhand between the pendulum at the pole, where the pivot is on the earth's ratation axis, and the ones mention and one similar that I think is in the Smithsonian Ist. in Wash. DC. I'm not going to drag out my Eulerian angle transformations and try to transform the omega cross velocity from pole case to get the local coordinate non-pole case equations and try to solve them. Feynman I once saw, and heard give a paper at a symposium (practically none of which I understood), but I never read anything by him, as I did't need his new quantum mechanics to treat my problems, and older quantum mechanics wasn't all that simple for me to start with. (Feynman's talk was far far the only such that I merely attempted to show that I wasn't sleeping, although that would have been more profitable for me at the time.)

Bogolieubof and K. Marterosin on QM at the International Congress on Theoretical Physics (I was still a chemist then), S. Charandraseker (the physics one), Marcel Ries on general relativity, E. Wigner and J. Robert Oppenheimer at Princeton on Einsein- Van Vleck, L. Pauling (Nobels)an others on QM, H. Kittell on solid physic, there were lots. Including Peter Debye (I an undergrad.). C. V. Raman's son was just a lab visitor. I wasn't much of a theoretian, but on a few rare occasions had to correct some older theory a bit.

Subject: RE: BS - Science Question for Amos or Wolfgang
From: catspaw49
Date: 12 Mar 01 - 08:44 PM

As I said above Jim, at the Center of Science and Industry in Columbus, Ohio. Also, for those who care, here's a pretty decent site.........FOUCAULT PENDULUM

Spaw

Subject: RE: BS - Science Question for Amos or Wolfgang
From: Jim Dixon
Date: 12 Mar 01 - 08:37 PM

As I recall, Foucault's pendulum rotates (that is, the plane of its oscillation rotates relative to the earth) at a varying rate depending on the latitude. A pendulum at the poles rotates 360 degrees in 24 hours. At other latitudes, it rotates more slowly. At the equator, it doesn't rotate at all.

A pendulum has to be very heavy, very delicately balanced and hung from a very stable mount, in order to observe this effect. There is one at the Museum of Science and Industry in Chicago, and one on the campus of Macalester College here in St. Paul. No doubt there are numerous others, but I can't name any.

Since St. Paul is at exactly 45 degrees latitude, you might think our pendulum would rotate 180 degrees in 24 hours, but that is not the case. The formula is more complicated than that, but I don't remember it.

Subject: RE: BS - Science Question for Amos or Wolfgang
From: Amos
Date: 12 Mar 01 - 08:33 PM

Because just to make it plain, burning usually means oxidizing, or combining with oxygen atoms. When hydrogen burns, the byproduct is atoms of hydrogen that have been married to all the oxygen they can take, or H2O (i.e., one atom of oxygen can grab two atoms of hydrogen).

A

Subject: RE: BS - Science Question for Amos or Wolfgang
From: GUEST,Bruce O.
Date: 12 Mar 01 - 08:20 PM

Banjer, Martin is right. Water is simply burnt hydrogen. However my specialty was H2O2, not all burnt and it sometimes goes the rest of the way by explosion.

Subject: RE: BS - Science Question for Amos or Wolfgang
From: GUEST,Bruce O.
Date: 12 Mar 01 - 08:16 PM

Sorry, Guest, yes.

Subject: RE: BS - Science Question for Amos or Wolfgang
From: MartinRyan
Date: 12 Mar 01 - 08:15 PM

Basically, because water is burnt-out hydrogen.

Regards

p.s. will all the blondes keep quiet, please!

Subject: RE: BS - Science Question for Amos or Wolfgang
From: Banjer
Date: 12 Mar 01 - 08:09 PM

Having discussed to great length the rotation of water as it departs, can we answer another question which has bothered me since middle school?
Water is comprised of Hydrogen (2 parts) and Oxygen...Chemically written as H₂O. Hydrogen is the same gas that caused the Hindenburg to explode...Oxygen supports combustion...so why won't water burn??

Subject: RE: BS - Science Question for Amos or Wolfgang
From: Amos
Date: 12 Mar 01 - 07:32 PM

Clearly I have arrived too late to add anything from my muzzy store of pseudo science and have been gainsaid by a master, for the overall benefit of the quality of information around here! Thanks, Bruce O!!!

A

Subject: RE: BS - Science Question for Amos or Wolfga
From: Murray MacLeod
Date: 12 Mar 01 - 07:18 PM

It's tornadoes that are caused by driving on the wrong side of the road Bill, not hurricanes. Hurricanes are caused by all the rowing boats containing Cuban refugees setting up assymetric wave patterns in the waters off the Florida coast.

Murray

Subject: RE: BS - Science Question for Amos or Wolfga
From: okthen
Date: 12 Mar 01 - 06:40 PM

Bert, I read (or saw) the same article about vortexes (vorteces?), and apparently, all the Americans have to do to avoid so many hurricanes is to drive on the other side of the road. No wonder we Brits have so few hurricanes as we drive on the proper side of the road.

cheers

bill

Subject: RE: BS - Science Question for Amos or Wolfga
From: GUEST
Date: 12 Mar 01 - 06:33 PM

Bruce Do you mean Hamiltonian?

Subject: RE: BS - Science Question for Amos or Wolfga
From: catspaw49
Date: 12 Mar 01 - 05:29 PM

You and I REALLY had some misspent youth Mark!! COSI in Columbus had a 3 story Foucault too with a beautiful inlaid marble compass rose at the base where they set the pegs up. Like you, I spent much time just watching and thinking about it.

Bruce---didn't Feynman's work in quantum mechanics involve movement around a center point, as in a spinning disc? As I recall he first began thinking of it watching a plate sail across a college cafeteria.

Spaw

Subject: RE: BS - Science Question for Amos or Wolfga
From: Mark Cohen
Date: 12 Mar 01 - 05:17 PM

Bruce, unless I'm mistaken (which is often the case), the pendulum doesn't have to be at the pole to see that effect. I believe it was Foucault who described this. The Franklin Institue Science Museum in Philadelphia, where I spent many childhood hours, has a 3-story Foucault pendulum in a stairwell, with wooden pegs or blocks set up in a circle on the floor. The blocks are sequentially toppled by the pendulum's swing throughout the day.

Aloha,
Mark

Subject: RE: BS - Science Question for Amos or Wolfga
From: GUEST,Bruce O.
Date: 12 Mar 01 - 05:12 PM

Coriolis force is almost fictitious. It's quantative description in classical mechanics seems worse than in quantum mechanics. (I've derived and applied coriolis matrix elements of the Haliltonian of vibrating-rotating polyatomic molecules. Assymetric rotors are a bit nasty to apply it too, but that's because of the way one has to handle assymetry. In symmetric tops it's not too bad, but they do depend on the symmetry of the vibrations involved [In methane Coriolis interactions get mixed in with so may other things that after many man years simple vibrational band spectra can only be quantatively fit up to J=12 (as of 12 years ago). A. R. at Oxford worked on this for years, and did so many model calculations on Oxford's computers, that he became the expert on them and computer methods. Deciding that computer technology was yet to primative to tackle methane well, he accepted the offer of the Computer Science Department to head that department, and resigned his chemistry professorship.] There is no Coriolis interaction between two totally symmetic vibrations.

Goldstein's 'Classical Mechanics' treats Coriolis interaction fairly completely, and shows that the force of it is less then .001 time the force of gravity (pulling the water into the drain). The drain problem isn't the only one where local perturbations can easily completely overshadow Coriolis effects.

One neat Coriolis effect is setting a pendulum swinging at the north or south pole. The poles are moving around the sun, but don't rotate with the earth. The pendulum's motion with respect to the sun is practically spaced fixed. However, to an observer at the pole (who does rotate with the earth) it looks like the pendulum is precessing, with one revolution each day.

The omega cross velocity vectors that give Coriolis force is a bit messy, because they're in a space fixed coordinate system, and we observers aren't, and find the equations for motion in our local xyz and 3d rotional coordinates are quite messy.

Subject: RE: BS - Science Question for Amos or Wolfga
From: gnu
Date: 12 Mar 01 - 03:17 PM

Guest,Bruce O. is correct. All things being equal, the drain water will swirl as per the standard. But if a butterfly flaps it's wing in Honduras.....

gnu

Subject: RE: BS - Science Question for Amos or Wolfga
From: Little Hawk
Date: 12 Mar 01 - 02:57 PM

Ah hah! The rotation of the Earth. Thanks, Mario, that's a pretty interesting site.

I guess the bathtub drain is so small that a variety of other factors alter the result, as Bert suggested.

- LH

Subject: RE: BS - Science Question for Amos or Wolfga
From: GUEST,Bruce O.
Date: 12 Mar 01 - 02:41 PM

Sorry MMario, I see you already noted it.

Subject: RE: BS - Science Question for Amos or Wolfga
From: GUEST,Bruce O.
Date: 12 Mar 01 - 02:40 PM

That's the Coriolis force on systems in motion, vaguely akin to centrifugal force, but it doesn't take much to disturb it so the water direction goes the wrong way.

Subject: RE: BS - Science Question for Amos or Wolfga
From: Bert
Date: 12 Mar 01 - 02:38 PM

The direction of the vortex "dahn the plug'ole" is due almost entirely to the physical shape and setting of the outlet in the basin and the piping immediately below it.

Tornadoes rotate counter clockwise in the northern hemisphere and I did read once, that they are exacerbated by cars driving on the right hand side of the road. It seems that the theory is, that two cars passing created a counterclockwise couple in the air. And much like the theory that loud noises can provide enough energy to trigger avalanches, they concluded that these small whirlwinds could create dust devils which could build up into tornadoes. They backed up the theory with graphs comparing the increase in tornadoes with the increase in motor traffic.

Bert.

Subject: RE: BS - Science Question for Amos or Wolfga
From: MMario
Date: 12 Mar 01 - 02:35 PM

see here

given the size of the drain - local factors probablty overide the Coriolis Acceleration.

Subject: BS - Science Question for Amos or Wolfga
From: Little Hawk
Date: 12 Mar 01 - 02:23 PM

Over the years I have read in numerous books that water goes in a clockwise spiral as it goes down a drain in the northern hemisphere, and counter-clockwise in the southern hemisphere.

Well, it sounded plausible, so I assumed it was correct.

Then I got around to actually observing what was happening in the bathtub, and lo and behold, sometimes it spins clockwise, sometimes it spins counter-clockwise, sometimes it reverses itself!

So way do all these books say it doesn't?

You'd think it would go either one way or the other, after all. What makes it decide to go one way as opposed to the other?

How about hurricanes? They spin in a predictable fashion according to the hemisphere, don't they?

I know it's trivial, but I really am wondering if the science community has any comment or explanation.

- LH