Date: Tue Mar 17 12:40:47 2009 Back to Contents ------------------------------------------------------------------------

Author: David Sturm

Subject: Re: Power Lines and cows?

Post:

Doug J. is on to something. If you have the old Welch-style coil & ring launcher that has the "tabletop" that allows any variety of side-demonstrations such as the shaded pole motor... park the wire bundle in the "down" position. Now, put a cow
magnet on top. Turn on the coil. That cow magnet will rattle all over the place (as will most any magnet, and refrigerator magnets are particularly peculiar). I've done this for table demo shows for ages. I think Colorado State's Little Shop has
a few table demo boxes using the same phenomena, and someone I know has a demo labeled "Temporary Guest Worker Jumping Magnet"

But that's a coil, so strong alternating magnetic fields make sense there. How could you get a similarly *strong* alternating magnetic field off a long wire, even with it being driven at 14 kVAC? Are the bundles of wire that make up the long
transmission line coiled in some fashion that I'm missing?

As the great-grandson of a farmer whose farm featured 30 head, and having fed a cow magnet to a cow (yuck: insert your hand a ways into their mouth), I'm thinking that even if I brought the coil up to the outside of the cow, it mightn't give a flip.
;) I'll look into seeing (being at a cow college land grant) if the folks over at our Witter Farm might let me try a quick experiment.

I think the previous lister who noted the cows see the towers as "trees" are on to something too, but my experience is cows don't give a damn about anything but grazing.

And I've seen them line up in a field in the manner described in the article but not due to magnetism: I think they've neglected to note that almost every field in the US midwest is N/S/E/W laid out the same Jeffersonian grid that the Northwest
Ordinance set forward. Following from that, most fallow fields have been farmed at some point with corn or other rowed vegetables. The fallowed field usually isn't level. It has gentle "grooves" (just look at this mapquest link:
http://www.mapquest.com/maps?city=Quincy&state=OH&address=Flowing+Well+Rd+%26+State+Route+235+N&zipcode=43343&country=US&latitude=40.25636&longitude=-83.97578&geocode=INTERSECTION#a/maps/l::Flowing+Well+Rd+&+State+Route+235+N:Quincy:OH:43343:US:40.25
636:-83.97578:intersection::1/m:hyb:12:40.25636:-83.97578:0:::::/io:0:::::f:EN:M:/e

for many subsequent years even after cultivation. The lower right quadrant is the O. D. Heath farm... notice in the fields S and E of the farmhouse that you can clearly see lines N/S and E/W resulting from previous cultivation of corn. The
diagonal lines in the field E of the house seem to be clouds, as the drainage there is more front to back.

The cows aren't lining up, they're just walking along the path of least change in potential energy, keeping their altitude constant.

Would you rather walk in a trough of a ruffled potato chip, or perpendicularly over and over and over like a bumpy road?

====================================================
David E G Sturm - sturmde@maine.edu - 1.207.581.1241
--Physics & Astronomy Instructional Laboratories
--Bennett Hall Lecture Demonstration Facilities
--Mainely Physics Road Show --PIRA President '08-09
Dept of Physics & Astronomy -- University of Maine
5709 Bennett Hall -- Orono ME 04469-5709
http://www.physics.umaine.edu/
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From tap-l-owner@lists.ncsu.edu Tue Mar 17 12:40:47 2009

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