HIT: Science question

[Carin Barwick <Bookpusher@aol.com>]

LM_NETTERS,
I called upon you today to help answer a science question for friends.
The question was:
"One of us (I won't mention any names until we get the answer) said that the
magnet would not work because magnets are polarized and depend on the
magnetic field on the earth to work.  Therefore, they would not work in
space.  The other one thought that was a bunch of hooey."

Thanks so much for your answers. The answer was: "Of course they Work!" Below
are some explanations (the last one is most detailed). Sometimes you guys
just seem so much smarter than I am. Thanks for lending your expertise!

Best,
Carin Barwick
LMS, Geneseo Elementary
Geneseo, NY
Bookpusher@aol.com

*****
Can't an electromagnetic field be created anywhere?
Flit McElligott, media
*****
The properties of magnetism have nothing to do with the earth ... otherwise
how would the magnetic boots of the astronauts work on the shuttle and other
space ships outside the influence of the earth ...

Aloha y'all   ...   Earl J.
Just an old Maui boy with a poor sense of direction ...   Fayetteville, NC
********
tell them to keep thinking, though ...

Now, does every planet have a magnetic field?  What makes it magnetic?
Would a magnetic compass work on every planet?
How would we tell directions on the surface of a planet without magnetism?

That ought to keep them busy over the spring break, eh?  8-)

Aloha y'all   ...   Earl J.
Just an old Maui boy with a poor sense of direction ...   Fayetteville, NC
*****
Friday 4/5/99
Carin, yes magnets work in space.  Polarized is used in two ways (at
least) one meaning is magnetic polarization or alignment of the magnetic
domains in the metal crystal structure that causes the magnetic field.
Another is optical polarization or alignment of the light photons'
electromagnetic fields (vibration in one plane) e.g. "polarized
sunglasses." YES magnets still have their magnetic fields in space!
Alan S. Miskin, M.S. Ed.S. (Physics '74)
*****
I am the husband of the librarian, and not the librarian
herself.

I am a registered nurse now, although I was a physics major
in college "the first time",  30 years ago.

The "hooey" point of view is correct.  I sincerely hope, for
the sake of American "education", the one who didn't say
hooey is NOT a teacher.  I think I'm appalled.  Even the
subject line is appalling; is it "trivial" to have a basic
understanding of science?

The earth has a magnetic field because of huge electrical
currents in the liquid iron core. Electrical currents induce
magnetic fields. That is why a compass works on earth; the
magnetic field of the earth pulls on the magnetized iron of
a compass needle.

If you put a magnet onto your refrigerator, it sticks.  It
sticks because the iron in the magnet is "magnetized".  This
means that all/most of the iron crystals inside the magnet
have been permanently aligned in the same direction by
artificial means, just as has the needle in your compass. If
you want it permanent you use hard iron; if not, soft iron.
The iron in your refrigerator is amorphous iron, each
crystal/molecule has a tiny magnetic field, but they all
point in various, helter-skelter, directions.  The force
from the magnet affects enough of these that mutual
attraction occurs.   All this has NOTHING to do with the
field of the earth, which, at the earth's surface, thousands
of miles away from the core, is very weak.  (Fields such as
this fall off as the SQUARE of the distance).  The
refrigerator is zero distance from the magnet.

 Another example would be loudspeakers or earphones.  They
work by the interaction between a permanent magnet and a
varying electrical field.

Earphones work on the moon. (Right? The astronauts could
hear the radio!!).  All of the refrigerator magnets on all
of the refrigerators on the moon are stuck just fine.  If
you are planning to pick up your  robot on the moon, your
electromagnet will work just  fine.  (An electromagnet, by
the way, can turn "on" and "off" because soft iron is used;
when the current is on, it's magnetic; when off, the iron in
the electromagnet reverts to magnetic randomness. The iron
in the robot's head is amorphous.)

On to the second inherent premise in the original question.
The surface of the  moon is not "space".  The moon is a
body, with an admittedly small atmosphere, and a gravity (of
course, because it has mass, eh?).  What it DOESN'T have is
the liquid core with currents flowing to cause it to be
magnetic.  So a COMPASS won't work on the moon, but
refrigerator magnets, loudspekers, earphones, and picking up
your iron robot all WILL work.  Likewise, out in actual
_space_, DITTO.

This is akin to the people who thought, circa 1920, that
rockets can't work in space because "there is no air for the
exhaust to push against".  Since rockets DO work in space,
it is apparent that THAT was hooey.  (Something about Sir
Isaac Newton and the law of equal and opposite reaction,
eh?)

Tom Mitchell, R.N., CCRN

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