#94770
02/07/2003 8:26 PM
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Joined: Sep 2001
Posts: 6,296
Carpal Tunnel
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Carpal Tunnel
Joined: Sep 2001
Posts: 6,296 |
And it's not really belaboring the obvious. It's pointing out interesting evidence. (I don't know anything about the history of clock making, but your point is interesting enough that I'm about to google the subject.  )
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#94771
02/07/2003 9:20 PM
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Joined: Mar 2000
Posts: 11,613
Carpal Tunnel
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Carpal Tunnel
Joined: Mar 2000
Posts: 11,613 |
I have been privileged to see the famous bat colony of Austin, Texas, emerge--once. I was too awed by the sheer numbers (up to a million and a half) to actually notice whether they wheeled clockwise or not, but as I cast my mind back, the image seems to be clockwise. Here's a link that explains about drag, lift, and thrust. Possibly these are subject to the Coriolis effect. http://www.ucmp.berkeley.edu/vertebrates/flight/physics.htmlHere is a link to the first of 5 or 6 pictures of them emerging. But if anyone can tell which way, you're a better observer than I am. http://www.pbase.com/image/264541
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#94772
02/07/2003 10:54 PM
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Joined: Dec 2000
Posts: 13,803
Carpal Tunnel
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Carpal Tunnel
Joined: Dec 2000
Posts: 13,803 |
Possibly these are subject to the Coriolis effect.
The reason that small scale phenomena don't show a noticeable correlation to Coriolis forces is that the Coriolis forces are small compared to other conditions. In the case of the sink drain, filling the sink from an off center tap will set up motion in the water that will not damp out before the drain is opened. If the water is circulating clockwise it will go down the drain clockwise. In the case of tornadoes, local topography will have a greater effect on the air flow than Coriolis forces will. The same is true for any aerodynamic forces that the bats will experience.
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#94773
02/07/2003 10:59 PM
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Joined: Jan 2001
Posts: 13,858
Carpal Tunnel
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Carpal Tunnel
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Posts: 13,858 |
Here is a very long list of links to bat sites. Well worth browsing. I found one picture of a lot of bats flying at dusk, but they did not appear to be circling. http://www.batbox.org/old_bat_house.html
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#94774
02/08/2003 12:43 AM
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Joined: Sep 2001
Posts: 872
old hand
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old hand
Joined: Sep 2001
Posts: 872 |
Jackie, the Austin bat colony of 1,500,000 that you saw is said to rise from their roost in the bridge counterclockwise. And so says this from the National Park Service...
"Hundreds of thousands of Mexican free-tailed bats, whirling counterclockwise, spill forth from a gigantic hole in the earth and are silhouetted against a colorful desert sky ... this is the bat flight experience at Carlsbad Caverns National Park."
And faldage, yes the coriolis effect is small on small sized structures but it tugs with unrelenting persistence. Animals that fly especially need every economy of energy that they can get.
By-the-way, in the morning after the night of feeding, the northern hemisphere bats fly back home, but they don't screw themselves (clockwise) back into the cave, instead they dive in a straight line to the mouth of the cave and on to their roost.
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#94775
02/08/2003 12:57 AM
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Joined: Dec 2000
Posts: 13,803
Carpal Tunnel
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Carpal Tunnel
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Posts: 13,803 |
Animals that fly especially need every economy of energy that they can get.
The point is that other forces swamp the Coriolis forces. It's not that it isn't there or that the samll animals can afford to ignore it; it's the fact that other things are more important at that scale.
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#94776
02/08/2003 1:56 AM
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Joined: Jan 2001
Posts: 13,858
Carpal Tunnel
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Carpal Tunnel
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Posts: 13,858 |
Dear Milo: I have looked at a lot of the sites. I finally saw a picture of the narrow gaps between
the concrete blocks that make spaces the bats can use in large numbers. I wondered how it
could be possible for the narrow range of temperatures the bats need.
One thing: I wonder how far the bats have to fly for all of them to find enough insects. It must
be quite a distance, covering a very large area.
Dear Milo: I have a new theory for you. One of the sites said the bats are classified as primates.
Is is possible that like humans they are right "handed", and have the right wing slightly more powerful
than the left, which would tend to make them circle to the left, counterclockwise? (taking my tongue
out of my cheek.) i'm sure Faldage will agree with me that is more probable than the Coriolis force.
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#94777
02/08/2003 3:17 AM
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Joined: Mar 2001
Posts: 4,189
Carpal Tunnel
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Carpal Tunnel
Joined: Mar 2001
Posts: 4,189 |
anti-clockwise here, although the main clock in my house runs in the direction traditoinally called anti-clockwise.That's because you guys Upunder dwell in counter-matter! 
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#94778
02/08/2003 3:20 AM
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Joined: Mar 2001
Posts: 4,189
Carpal Tunnel
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Carpal Tunnel
Joined: Mar 2001
Posts: 4,189 |
Well, milum, you could always look at it this way...no matter which direction the bats fly in...guano is still guano!
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#94779
02/08/2003 10:53 AM
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Joined: Sep 2001
Posts: 6,296
Carpal Tunnel
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Carpal Tunnel
Joined: Sep 2001
Posts: 6,296 |
Here's an elementary bat quiz that none of us here would have any problem in scoring 100% on. The quiz is set up so that you can pretty much tell the answer without knowing it, but you might have a child somewhere who'd like to take the quiz. Do not go to this site if you're not curious about elementary bat quizzes! http://www.cccoe.k12.ca.us/bats/quiz.html
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#94780
02/08/2003 12:15 PM
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Joined: Dec 2000
Posts: 13,803
Carpal Tunnel
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Carpal Tunnel
Joined: Dec 2000
Posts: 13,803 |
hat is more probable than the Coriolis force.
Not if I have to accept the notion that they are primates to do it. What's the site, Dr Bill?
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#94781
02/08/2003 1:47 PM
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Joined: Jan 2001
Posts: 13,858
Carpal Tunnel
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Carpal Tunnel
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Dear FakdageL I'll have a hell of a time finding that site again. It said they were primates
on the basis of having mammary glands located in the pectoral area. I too wondered why
that was enough to relate them to us.
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#94782
02/08/2003 2:44 PM
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Joined: Jan 2001
Posts: 13,858
Carpal Tunnel
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Carpal Tunnel
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Here ;is a site about fling fox, fruit bats, saying they meet criteria to be called primates.
[urk]www.batcon.org/batsmag/v3n2-1.html[/url]
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#94783
02/08/2003 2:53 PM
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Joined: Mar 2001
Posts: 4,189
Carpal Tunnel
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Carpal Tunnel
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Posts: 4,189 |
Coriolis force.
So which way does a baseball rotate when it hits and leaves the bat? Does it rotate differently in each hemisphere?
And what about other batted (cricket) and thrown objects...does the Coriolus affect them in any way, or is it simply the centrifugal spin of contact? I know the spin of thrown objects is almost wholly influenced by the style of release, but are there any hemispheric factors at work in this?
And what about a boomerang...will it come back in an oppsite arc in the Northern hemisphere?
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#94784
02/08/2003 4:35 PM
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Joined: Jul 2000
Posts: 3,467
Carpal Tunnel
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Carpal Tunnel
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Posts: 3,467 |
Well, damn! Bats are primates, according to the OED, wihch lists primates as the highest order of the Mammalia, including man, monkeys, lemurs, and in the Linnaean order, bats.
Now there is a trivia question that deserves to be on Jeopardy.
TEd
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#94785
02/08/2003 6:37 PM
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Joined: Sep 2001
Posts: 872
old hand
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old hand
Joined: Sep 2001
Posts: 872 |
Bats are Primates.
Thats it. I've had it. Next thing you know we'll be closing caves to protect the homes of our distant cousins the bat.
Wait a minute. We already are. Five of the caves that I used to visit in Alabama have been closed to humans for the sake of our little precious guano making idiot cousin the bat.
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#94786
02/08/2003 7:07 PM
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Joined: Jul 2002
Posts: 742
old hand
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old hand
Joined: Jul 2002
Posts: 742 |
>Five of the caves that I used to visit in Alabama have been closed to humans for the sake of our little precious guano making idiot cousin the bat.
Well, if you're upset that you've been denied further permission to play in your relatives' homes, why not invite them to come play in yours? Turnabout is fair play, is it not?
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#94787
02/08/2003 7:58 PM
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Joined: Jan 2001
Posts: 13,858
Carpal Tunnel
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Carpal Tunnel
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Posts: 13,858 |
And he could make a fortune peddling bat guano.
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#94789
02/09/2003 1:19 AM
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Joined: Jan 2001
Posts: 13,858
Carpal Tunnel
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Carpal Tunnel
Joined: Jan 2001
Posts: 13,858 |
Don't let it drive you batty.
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