Magnetizing a Paperclip?
jeff_wisnia
I just watched the movie "The Edge" on Netflix and thought it odd that
the central character magnetized a paperclip to make a floating compass
by rubbing it on his silk shirt cuff.
I've shown my kids a floating compass after magnetizing a sewing needle
by sliding it against a rare earth magnet, but agsinst silk, I think not.
I'm aware you can magnetize a steel rod by holding it in one orientation
and repeatedly whacking it with a hammer, but rubbing steel on silk
strikes me as BS.
Am I correct, and was that just a bit of artistic license for thast movie?
Thanks Guys, and Happy Holidays,
Jeff
--
Jeffry Wisnia
(W1BSV + Brass Rat '57 EE)
The speed of light is 1.8*10e12 furlongs per fortnight.
D.F. Manno
jeff_wisnia <jwisnia...@conversent.net> wrote:
> I just watched the movie "The Edge" on Netflix and thought it odd that
> the central character magnetized a paperclip to make a floating compass
> by rubbing it on his silk shirt cuff.
>
> I've shown my kids a floating compass after magnetizing a sewing needle
> by sliding it against a rare earth magnet, but agsinst silk, I think not.
>
> I'm aware you can magnetize a steel rod by holding it in one orientation
> and repeatedly whacking it with a hammer, but rubbing steel on silk
> strikes me as BS.
>
> Am I correct, and was that just a bit of artistic license for thast movie?
You appear to be correct:
<http://www.wildwoodsurvival.com/survival/navigation/rbimprovisedcompass0
1.html> or <http://snipurl.com/1pumty>
--
D.F. Manno | dfm...@mail.com
Remember the reason for the season - keep Saturn in Saturnalia.
Veronique
wrote:
> I'm aware you can magnetize a steel rod by holding it in one orientation
> and repeatedly whacking it with a hammer, but rubbing steel on silk
> strikes me as BS.
http://www.survivaltopics.com/survival/make-a-floating-needle-compass/
"To make a compass you first need to magnetize a needle or other thin
object that contains iron by stroking it with a piece of silk. "
V.
--
Veronique Chez Sheep
Don K
news:8f19f56a-6b51-4665...@f21g2000prn.googlegroups.com...
I just learned something new.
Now I need to learn where to find silk in the wilderness.
Don
John Hatpin
That's easy. Just follow caterpillars around and collect anything they
exude. If you can make a pair of stockings with any of it, that's
probably silk.
--
John Hatpin
jeff_wisnia
> In article <Z-adnc26D5pHB4vQ...@giganews.com>,
> jeff_wisnia <jwisnia...@conversent.net> wrote:
>
>
>>I just watched the movie "The Edge" on Netflix and thought it odd that
>>the central character magnetized a paperclip to make a floating compass
>>by rubbing it on his silk shirt cuff.
>>
>>I've shown my kids a floating compass after magnetizing a sewing needle
>>by sliding it against a rare earth magnet, but agsinst silk, I think not.
>>
>>I'm aware you can magnetize a steel rod by holding it in one orientation
>>and repeatedly whacking it with a hammer, but rubbing steel on silk
>>strikes me as BS.
>>
>>Am I correct, and was that just a bit of artistic license for thast movie?
>
>
> You appear to be correct:
>
> <http://www.wildwoodsurvival.com/survival/navigation/rbimprovisedcompass0
> 1.html> or <http://snipurl.com/1pumty>
>
Thanks, that was one heck of an article on the subject.
But it also appeared to invalidate my recollection that you can
magnetize a steel rod by aligning it with the earth's magnetic field and
whacking it with a hammer several times. But the author only said that
he couldn't magnetize a steel tod enough that way to pick up a pin. He
didn't say he made any measurements to see if he'd created a weaker but
still detectible magnetic field/
Veronique
> "Veronique" <veroniqueuni...@gmail.com> wrote in message
Surely you survivalists have silk longjohns?
Paul Ciszek
>the central character magnetized a paperclip to make a floating compass
>by rubbing it on his silk shirt cuff.
>
>I've shown my kids a floating compass after magnetizing a sewing needle
>by sliding it against a rare earth magnet, but agsinst silk, I think not.
>
>I'm aware you can magnetize a steel rod by holding it in one orientation
>and repeatedly whacking it with a hammer, but rubbing steel on silk
>strikes me as BS.
>
>Am I correct, and was that just a bit of artistic license for thast movie?
It sounds like someone was confusing magnetism with electrostatics.
It seems like certain metal forming processes leave parts magnetized
whether you want them to be or not, but I don't recall if paperclips
were among them. Try straightening one out, and see if it acts like
a weak compass needle on its own.
--
Please reply to: | "The anti-regulation business ethos is based on
pciszek at panix dot com | the charmingly naive notion that people will not
Autoreply is disabled | do unspeakable things for money." -Dana Carpender
Nick Spalding
on Sat, 25 Dec 2010 23:02:56 -0500:
Back in the day ships were riveted and did pick up quite strong
magnetisation which led to the contrivances that had to be put in the
compass binnacle to correct for it, the most obvious being two large
iron balls. It was also what triggered magnetic mines until the idea of
putting degaussing cables fed from a generator to neutralise the ship's
magnetism. Whether modern welded ships are so much affected I don't
know.
--
Nick Spalding
dilbert firestorm
battery regardless of voltage.
--
<---=««-Dilbert Firestorm-»»=--->
Zizzle that Fire - it's Zizzle Time !!!!!!!
N Jill Marsh
>"Veronique" <veroniq...@gmail.com> wrote in message
>news:8f19f56a-6b51-4665...@f21g2000prn.googlegroups.com...
>>On Dec 25, 5:31 pm, jeff_wisnia <jwisniadumpt...@conversent.net>
>>wrote:
>>> I'm aware you can magnetize a steel rod by holding it in one orientation
>>> and repeatedly whacking it with a hammer, but rubbing steel on silk
>>> strikes me as BS.
No, it works fine. I don't know about a paperclip, that's a lot of
mass, but silk and a needle does it.
>>http://www.survivaltopics.com/survival/make-a-floating-needle-compass/
>>"To make a compass you first need to magnetize a needle or other thin
>>object that contains iron by stroking it with a piece of silk. "
>
>I just learned something new.
>Now I need to learn where to find silk in the wilderness.
If the weather is at all cool, I'm generally covered in it.
nj"not that you'll find me"m
--
"All I can say is that the work has been done well in every way."
Don K
news:vifeh69hjboqd977c...@4ax.com...
> On Sat, 25 Dec 2010 21:42:34 -0500, "Don K" <d...@comcast.net> wrote:
>
>>"Veronique" <veroniq...@gmail.com> wrote in message
>>news:8f19f56a-6b51-4665...@f21g2000prn.googlegroups.com...
>>>On Dec 25, 5:31 pm, jeff_wisnia <jwisniadumpt...@conversent.net>
>>>wrote:
>>>> I'm aware you can magnetize a steel rod by holding it in one orientation
>>>> and repeatedly whacking it with a hammer, but rubbing steel on silk
>>>> strikes me as BS.
>
> No, it works fine. I don't know about a paperclip, that's a lot of
> mass, but silk and a needle does it.
>
>>>http://www.survivaltopics.com/survival/make-a-floating-needle-compass/
>>>"To make a compass you first need to magnetize a needle or other thin
>>>object that contains iron by stroking it with a piece of silk. "
>>
>>I just learned something new.
>>Now I need to learn where to find silk in the wilderness.
>
> If the weather is at all cool, I'm generally covered in it.
Ok. If I ever get lost, I'll just look for you.
Thanks
Don
Don K
Will cat's fur work?
It might be easier to find a dead cat in the woods.
What about feathers?
Birds migrate north and south, so feathers might be good for this.
Don
groo
Don't see why not, if you can build up a static charge on it. Moving
electric charge = magnetic field.
> What about feathers?
> Birds migrate north and south, so feathers might be good for this.
>
Evidence seems to indicate that bird's ability to sense the magnetic
field has to do with structures in their brains (and beaks, IIRC). No
feathers involved. But if you can charge them up, they should work as
well as cat fur.
--
"There's a difference between keeping an open mind and letting your brain
leak out." - Dana Carpender
Hieronymus Agricola
(in article <if7fh9$jpk$1...@news.eternal-september.org>):
<<<...>>>
> Ok. If I ever get lost, I'll just look for you.
"Well I told her I was lost
and she told me all about the Pentecost.
And I seen that girl as the road to my survival."
-- Paul Simon
Lee Ayrton
One of the benefits of section-assembly techniques in WWII-era US
shipyards was discordant magnetic fields in the various assemblies.
Under this system entire sections of a vessel were constructed and fitted
out, then the sections were assembled and welded together. Because they
were constructed in the yard instead of on the ways their magnetic
orientation could be different. Without a unified magnetic field these
vessels tended to not trigger the early magnetic-sensing mines.
Bob
product either totally non-functional or pretty crappy. An example is
those for household cleaners that call for combining vinegar and
baking soda. The only sort of cleaning that'd work on would be
opening a drain, and then only if the ingredients are poured in
serially and allowed to make gas in situ. These recipes wouldn't
usually get passed on by people who actually tried them, because
they'd just make a mess once that mixture was made. Presumably
somebody thought baking soda was good and vinegar was good, why not
combine them, and wrote a recipe on mere speculation.
I have seen some reports of people who've actually tried one of these
mixtures who figured the fizzing was just a transient problem that
made the mixing inconvenient, and so advised people to mix in a wide
mouthed container with lots of head space, and then to bottle it after
it stops fizzing. OK, you can do that, but you'll get a product which
is less effective than if either the vinegar or the baking soda was
omitted.
There's a bubble bath recipe that's widely disseminated, often in the
form of an article that's pirated and plagiarized, that calls for soap
as its base. Probably many who've prepared it haven't actually used
it for that, and plenty of those who have used it wonder what went
wrong when it didn't work for them, and write of their perplexity on
message boards. One pirated article promoting this recipe gets things
really screwed up in thinking that unsaponified coconut oil will boost
its foam, when in reality only saponified coconut oil (i.e. coconut
soap) lathers -- an example like that of the magnetizing hair or silk
that must've originated due to lack of understanding of the original
material.
Then there was the rumor of an approach to Earth of Mars so close that
its apparent diameter would approximate that of the Moon.
I saw these sorts of misunderstandings in my students' papers, but
they weren't writing for the Internet.
Bob in the Bronx
Charles Wm. Dimmick
I'm given to understand that whenever you are planning to wander in the
woods you should take along a deck of cards. If you get lost, then break
open the pack and start playing solitaire. Within 20-30 minutes some
idiot will come along and start kibitzing your play.
Charles
Charles Wm. Dimmick
Birds have a pigment in their right eye [cryptochrome] which in the
presence of blue or ultraviolet light is sensitive to the earth's
magnetic field. Some birds are much more sensitive than others. Many
birds also have small magnetic particles in their olfactory lobes, and
seem to integrate the signals from their right eye with the signals from
the olfactory lobes. Strangely enough, they cannot detect differences in
the declination of the earth's magnetic field and instead rely on the
inclination and strength of the field instead.
charles
Pierre Jelenc
>
> No, it works fine. I don't know about a paperclip, that's a lot of
> mass, but silk and a needle does it.
Have you tried it personally? If so, how did you find an unmagnetized
needle as a control? In a household, every piece of magnetizable metal is
already magnetized by magnets or electromagnets in appliances, speakers,
etc.
[I don't believe a word of it: Silk causes static electricity on non-
conductors such as glass, plastic, or people in rubber-soled slippers, but
it does nothing to condutors, and nothing to magnetic domains.]
Pierre
--
Pierre Jelenc
The Gigometer www.gigometer.com
The NYC Beer Guide www.nycbeer.org
Veronique
> On 12/26/2010 8:21 AM, Don K wrote:
>
>
>
That's a bit like the trick I learned in college: when waiting for a
bus, have someone in your party light up a cigarette. The bus will be
arrive immediately.
Bill Turlock
Riiight, Les
Bill Turlock
This one is true.
Don K
>N Jill Marsh <njm...@gmail.com> writes:
>>
>> No, it works fine. I don't know about a paperclip, that's a lot of
>> mass, but silk and a needle does it.
>
> Have you tried it personally? If so, how did you find an unmagnetized
> needle as a control? In a household, every piece of magnetizable metal is
> already magnetized by magnets or electromagnets in appliances, speakers,
> etc.
You would first test to see if it acts as a compass.
If it doesn't, then proceed with the silk rub and test it again.
>
> [I don't believe a word of it: Silk causes static electricity on non-
> conductors such as glass, plastic, or people in rubber-soled slippers, but
> it does nothing to condutors, and nothing to magnetic domains.]
A voltage difference causes current to flow in conductors, and that current
creates a magnetic field.
Any flow of electrons creates a magnetic field in accordance with
right-hand-rule:
Make a fist with your right hand. Stick out the thumb.
The thumb points in the direction of current flow.
The fingers point in the direction of the magnetic field wrapping
around the current flow.
Don
John Hatpin
I used to do that for taxis, on the same principle. It was extremely
successful, as reliable as confirmation bias itself.
--
John Hatpin
K_S_ONeill
> "Pierre Jelenc" <r...@panix.com> wrote in messagenews:if7vd8$5u3$1...@reader1.panix.com...
Did you see the page Mr Manno pointed to in the first response?
--
Kevin
Hactar
Don K <d...@comcast.net> wrote:
> "Pierre Jelenc" <rc...@panix.com> wrote in message
> news:if7vd8$5u3$1...@reader1.panix.com...
> >N Jill Marsh <njm...@gmail.com> writes:
> >>
> >> No, it works fine. I don't know about a paperclip, that's a lot of
> >> mass, but silk and a needle does it.
> >
> > Have you tried it personally? If so, how did you find an unmagnetized
> > needle as a control? In a household, every piece of magnetizable metal is
> > already magnetized by magnets or electromagnets in appliances, speakers,
> > etc.
>
> You would first test to see if it acts as a compass.
> If it doesn't, then proceed with the silk rub and test it again.
>
> > [I don't believe a word of it: Silk causes static electricity on non-
> > conductors such as glass, plastic, or people in rubber-soled slippers, but
> > it does nothing to condutors, and nothing to magnetic domains.]
>
> A voltage difference causes current to flow in conductors, and that current
> creates a magnetic field.
For a very very short time. I'm talking nanoseconds. Then the charge is
gone.
--
-eben QebWe...@vTerYizUonI.nOetP http://royalty.mine.nu:81
SAGITTARIUS: All your friends are laughing behind your back... kill
them. Take down all those naked pictures of Ernest Borgnine you've
got hanging in your den. -- Weird Al, _Your Horoscope for Today_
Mac
wrote:
>I've seen chemical recipes widely disseminated that would result in
>product either totally non-functional or pretty crappy.
I once had the wince-inducing experience of watching a senior engineer
NCO - i.e., somebody who shoulda known better - demonstrate improvised
napalm.
With powdered laundry detergent. "Tide", I believe.
Bob
> On Sun, 26 Dec 2010 07:49:15 -0800 (PST), Bob <robg...@bestweb.net>
> wrote:
>
> >I've seen chemical recipes widely disseminated that would result in
> >product either totally non-functional or pretty crappy.
>
> I once had the wince-inducing experience of watching a senior engineer
> NCO - i.e., somebody who shoulda known better - demonstrate improvised
> napalm.
>
> With powdered laundry detergent. "Tide", I believe.
How'd that work? My understanding is that napalms can be produced
with various materials; is it not forgiving enough to use powdered
Tide?
Lee Ayrton
Needs phosphates, doesn't it?
Lesmond
>On Dec 26, 9:30ÿam, "Charles Wm. Dimmick" <cdimm...@snet.net> wrote:
>> On 12/26/2010 8:21 AM, Don K wrote:
>>
>>
>>
>> > "N Jill Marsh"<njma...@gmail.com> ÿwrote in message
>> >> On Sat, 25 Dec 2010 21:42:34 -0500, "Don K"<d...@comcast.net> ÿwrote:
>
>
>> >>> Now I need to learn where to find silk in the wilderness.
>>
>> >> If the weather is at all cool, I'm generally covered in it.
>>
>> > Ok. If I ever get lost, I'll just look for you.
>>
>> I'm given to understand that whenever you are planning to wander in the
>> woods you should take along a deck of cards. If you get lost, then break
>> open the pack and start playing solitaire. Within 20-30 minutes some
>> idiot will come along and start kibitzing your play.
>
>
>That's a bit like the trick I learned in college: when waiting for a
>bus, have someone in your party light up a cigarette. The bus will be
>arrive immediately.
Yes! Or back when you could smoke in restaurants. If you really want your
food, light up.
--
If there's a nuclear winter, at least it'll snow.
Mac
wrote:
>On Dec 26, 6:21 pm, Mac <anmcc...@alumdotwpi.edu> wrote:
>
>> On Sun, 26 Dec 2010 07:49:15 -0800 (PST), Bob <robg...@bestweb.net>
>> wrote:
>>
>> >I've seen chemical recipes widely disseminated that would result in
>> >product either totally non-functional or pretty crappy.
>>
>> I once had the wince-inducing experience of watching a senior engineer
>> NCO - i.e., somebody who shoulda known better - demonstrate improvised
>> napalm.
>>
>> With powdered laundry detergent. "Tide", I believe.
>
>How'd that work?
Horribly. About as well as sand or sawdust would. Mighta benefited
from a small amount of water.
> My understanding is that napalms can be produced
>with various materials; is it not forgiving enough to use powdered
>Tide?
Nah. You need either a soap, in the old-fashioned sense -some
lye-treated fat or oil' or a thickening gasoline soluble substance,
like polystyrene or some solid paraffin.
Don K
news:9a097ef5-1be2-4c9b...@t35g2000yqj.googlegroups.com...
>Did you see the page Mr Manno pointed to in the first response?
No, the page didn't load right.
But I went back now and got it to load ok.
What's your point?
Don
Pierre Jelenc
> "Pierre Jelenc" <rc...@panix.com> wrote in message
> news:if7vd8$5u3$1...@reader1.panix.com...
> >N Jill Marsh <njm...@gmail.com> writes:
> >>
> >> No, it works fine. I don't know about a paperclip, that's a lot of
> >> mass, but silk and a needle does it.
> >
> > Have you tried it personally? If so, how did you find an unmagnetized
> > needle as a control? In a household, every piece of magnetizable metal is
> > already magnetized by magnets or electromagnets in appliances, speakers,
> > etc.
>
> You would first test to see if it acts as a compass.
> If it doesn't, then proceed with the silk rub and test it again.
Right. But there is no non-magnetized ferromagnetic object in my
apartment, and --I bet-- in all households of people with appliances and
refrigerator magnets. (I tried a pin, a needle, a plastic-coated paper
clip, and a naked paper clip; they all oriented N-S right away. As a non-
ferromagnetic control I used a plastic toothpick and a piece of copper
wire; they did nothing.)
> > [I don't believe a word of it: Silk causes static electricity on non-
> > conductors such as glass, plastic, or people in rubber-soled slippers, but
> > it does nothing to conductors, and nothing to magnetic domains.]
>
> A voltage difference causes current to flow in conductors, and that current
> creates a magnetic field.
There is no voltage difference or current flow within a conductor
subjected to a static charge! That's why it's called *static*.
John Hatpin
I think it would still get the prompt attention of the waiter.
--
John Hatpin
Veronique
> >news:if7vd8$5u3$1...@reader1.panix.com...
> > >N Jill Marsh <njma...@gmail.com> writes:
>
> > >> No, it works fine. I don't know about a paperclip, that's a lot of
> > >> mass, but silk and a needle does it.
>
> > > Have you tried it personally? If so, how did you find an unmagnetized
> > > needle as a control? In a household, every piece of magnetizable metal is
> > > already magnetized by magnets or electromagnets in appliances, speakers,
> > > etc.
>
> > You would first test to see if it acts as a compass.
> > If it doesn't, then proceed with the silk rub and test it again.
>
> Right. But there is no non-magnetized ferromagnetic object in my
> apartment, and --I bet-- in all households of people with appliances and
> refrigerator magnets. (I tried a pin, a needle, a plastic-coated paper
> clip, and a naked paper clip; they all oriented N-S right away. As a non-
> ferromagnetic control I used a plastic toothpick and a piece of copper
> wire; they did nothing.)
Next, I think you should make napalm out of Tide.
Slow Motion Apocalypse
> On Sat, 25 Dec 2010 21:42:34 -0500, "Don K" <d...@comcast.net> wrote:
> >"Veronique" <veroniqueuni...@gmail.com> wrote in message
> >news:8f19f56a-6b51-4665...@f21g2000prn.googlegroups.com...
> >>On Dec 25, 5:31 pm, jeff_wisnia <jwisniadumpt...@conversent.net>
> >>wrote:
> >>> I'm aware you can magnetize a steel rod by holding it in one orientation
> >>> and repeatedly whacking it with a hammer, but rubbing steel on silk
> >>> strikes me as BS.
>
> mass, but silk and a needle does it.
>
> >>"To make a compass you first need to magnetize a needle or other thin
> >>object that contains iron by stroking it with a piece of silk. "
>
> >I just learned something new.
>
> If the weather is at all cool, I'm generally covered in it.
>
>
> --
> "All I can say is that the work has been done well in every way."
Did you have a Happy Lemmy's Birthday?
Bob
It doesn't.
Bob
> On Sun, 26 Dec 2010 15:47:45 -0800 (PST), Bob <robg...@bestweb.net>
> wrote:
> > My understanding is that napalms can be produced
> >with various materials; is it not forgiving enough to use powdered
> >Tide?
> Nah. You need either a soap, in the old-fashioned sense -some
> lye-treated fat or oil' or a thickening gasoline soluble substance,
> like polystyrene or some solid paraffin.
Do you think the problem is that the surfactants in Tide powder
weren't oleaginous enough, or that inorganic salts in the powder
interfered too much? Was it the ultra powder, or a previous powder
that he tried? The ultra would've have less of the inorganic salt.
Don K
> Don K <d...@comcast.net> writes:
>> "Pierre Jelenc" <rc...@panix.com> wrote in message
>> news:if7vd8$5u3$1...@reader1.panix.com...
>> > conductors such as glass, plastic, or people in rubber-soled slippers, but
>> > it does nothing to conductors, and nothing to magnetic domains.]
>>
>> A voltage difference causes current to flow in conductors, and that current
>> creates a magnetic field.
>
> There is no voltage difference or current flow within a conductor
> subjected to a static charge! That's why it's called *static*.
On this cold, dry winter's night, I got up off the couch, walked across
the carpeted room, and touched the metal doorknob to let the dog out.
There was a spark and I got an electrostatic shock.
If I repeated the procedure using a metal clip to touch the doorknob,
there would still be a spark. Current would flow thru the metal clip to
whatever it touched.
If the metal clip touches only object1, its voltage is the same
as object 1. If you then make it also touch object2, which is at a
different voltage, there will be current flowing thru the metal.
Don
Mac
wrote:
>On Dec 26, 9:39 pm, Mac <anmcc...@alumdotwpi.edu> wrote:
No, I thought that the problem was a little learning. Some one
thought "soap's soap, it's all pretty much the same," and apparently
continued to think it even after something that was supposed to look
like slightly runny jello looked exactly like damp sand.
Lee Ayrton
My bad chemistry guess. I was thinking ANFO and nitrite. I'll shaddup
now.
N Jill Marsh
>"N Jill Marsh" <njm...@gmail.com> wrote in message
>news:vifeh69hjboqd977c...@4ax.com...
>> On Sat, 25 Dec 2010 21:42:34 -0500, "Don K" <d...@comcast.net> wrote:
>>>I just learned something new.
>>>Now I need to learn where to find silk in the wilderness.
>> If the weather is at all cool, I'm generally covered in it.
>
>Ok. If I ever get lost, I'll just look for you.
No rubbing anything up against me without permission, unless it's a
martini.
(Another sure fire way of being rescued in the woods, start making a
martini.)
nj"tastier than solitaire"m
N Jill Marsh
<slowmotion...@rocketmail.com> wrote:
>Did you have a Happy Lemmy's Birthday?
We celebrated by pouring two beer over a macbook. On the train.
nj"with muttonchops"m
Pierre Jelenc
>
> On this cold, dry winter's night, I got up off the couch, walked across
> the carpeted room, and touched the metal doorknob to let the dog out.
> There was a spark and I got an electrostatic shock.
That's because you are discharging the charge on your body, not any charge
on the metal. The metal is grounded, it is at zero volts. If you wore
metal shoes instead of your slippers at home, you would not gather a
static charge.
> If I repeated the procedure using a metal clip to touch the doorknob,
> there would still be a spark. Current would flow thru the metal clip to
> whatever it touched.
That's irrelevant. The current does not flow in the paperclip before you
ground it.
> If the metal clip touches only object1, its voltage is the same
> as object 1. If you then make it also touch object2, which is at a
> different voltage, there will be current flowing thru the metal.
And? That has zero bearing on rubbing a needle with a silk cloth! You
cannot charge metal by rubbing it. A static electricity generator (e.g.
Van de Graaff) works by rubbing two different, non-conducting surfaces
together, and gathering the charge with a metal brush and into a
capacitor. Or rubbing rubber soles against a wool carpet and gathering the
charge into a capacitor made of a damp body with a paperclip, and a
doorknob.
Furthermore, even if there were a current, the magnetic field would be
orthogonal to it, i.e. across the needle, not along it. The needle should
then align east-west, with its *long* sides toward north and south.
Bob
> On Sun, 26 Dec 2010 20:23:15 -0800 (PST), Bob <robg...@bestweb.net>
> wrote:
> >> > My understanding is that napalms can be produced
> >> >with various materials; is it not forgiving enough to use powdered
> >> >Tide?
>
> >> Nah. You need either a soap, in the old-fashioned sense -some
> >> lye-treated fat or oil' or a thickening gasoline soluble substance,
> >> like polystyrene or some solid paraffin.
>
> >Do you think the problem is that the surfactants in Tide powder
> >weren't oleaginous enough, or that inorganic salts in the powder
> >interfered too much? Was it the ultra powder, or a previous powder
> >that he tried? The ultra would've have less of the inorganic salt.
>
> No, I thought that the problem was a little learning. Some one
> thought "soap's soap, it's all pretty much the same," and apparently
> continued to think it even after something that was supposed to look
> like slightly runny jello looked exactly like damp sand.
No, I meant the problem that kept it from working in spite of too
little learning.
I ask about this one in particular because it's similar to that faced
by the people who had various craft recipes calling for soap powder or
flakes, which they had obtained as Ivory Snow in the USA, after 1993,
when the product had been reformulated into non-soap. Ivory Flakes
had been discontinued a few years earlier, and Lux Flakes had stopped
distribution in the USA as well. Some people probably continued with
the new stuff in ignorance of the reformulation -- but many of the
recipes turned out to work anyway, albeit probably not quite as well.
At the time the recipes were concocted they'd been careful to specify
soap, because other laundry and all-purpose detergent powders at the
time contained large amounts of inorganic salts that made the craft
products far too crumbly rather than sticky-pliable like soap.
However, by the time the formula changed, Ivory Snow was reformulated
soaplessly as an ultra-concentrated powder, and the ultras had less of
those inorganic salts, so the product of wetting and drying, while
still crumblier than soap, was at least adequate to make sculptures,
etc.
Most soap powders, except for really cheap, inferior ones, had never
contained more than a small percentage of inorganic salts like sodium
carbonate, and Ivory Snow in partiular was nearly all soap, like soap
flakes. So this is what's funny about the recipes all over the
Internet now for making your own landry detergent. Many of those
recipes (I could simply say "recipe", because they're mostly just
copies of one) are presented super-redundantly in video form.
(Have you noticed how everybody's a copycat on YouTube? Do these
people really think the worlds needs ANOTHER presentation to show them
how to do the same thing? I understand when it's children doing it,
because for them it's just an exercise in doing a present'n, but
adults? Like they don't do a search first and see it's not only all
over the place in text but also people acting it out in video?)
Anyway, this recipe isn't exactly useless, but it's defeinitely
inferior. It calls for grated soap, washing soda, and borax. Why
BOTH washing soda and borax, I don't know, but at least most of them
don't call for vinegar or lemon juice in addition (a few do). Anyway,
it calls for a LOT of soda and borax in proportion to the soap.
That's the sort of thing that would've been considered laughably
inferior in the last century -- poor cleaning, hard on fabrics,
tending to make clothes scratchy. They point out that you can use it
in those HE machines without over-sudsing, but what they don't realize
is that that's because there's so little soap in there; the alkali and
salt content depresses the foam, but if they had enough soap in there
to clean well, it would lather up a HE machine seriously.
Bob in the snowed-over (and it ain't Ivory) Bronx
Bob
Not soon enough. That doesn't have nitrite, either.
groo
> And? That has zero bearing on rubbing a needle with a silk cloth! You
> cannot charge metal by rubbing it.
I think the point is to get a static charge on the silk cloth first. Being
a lousy conductor, the silk can't transfer much of its charge to the metal.
But moving the precharged silk across the metal creates a small magnetic
field.
--
"There's a difference between keeping an open mind and letting your brain
leak out." - Dana Carpender
Lee Ayrton
>> >> > How'd that work? My understanding is that napalms can be produced
>> >> > with various materials; is it not forgiving enough to use powdered
>> >> > Tide?
>>
>> >> Needs phosphates, doesn't it?
>>
>> > It doesn't.
>>
>> My bad chemistry guess. I was thinking ANFO and nitrite. I'll shaddup
>> now.
>
> Not soon enough. That doesn't have nitrite, either.
Dang. now I need a time machine.
Lee Ayrton
> "Charles Wm. Dimmick" wrote:
>> On 12/26/2010 8:58 AM, groo wrote:
>> > "Don K"<d...@comcast.net> wrote:
[big snip]
>> >> Birds migrate north and south, so feathers might be good for this.
>> >>
>> > Evidence seems to indicate that bird's ability to sense the magnetic
>> > field has to do with structures in their brains (and beaks, IIRC). No
>> > feathers involved. But if you can charge them up, they should work
>> > as well as cat fur.
>>
>> Birds have a pigment in their right eye
>
> Riiight, Les
>
>> [cryptochrome] which in the
>> presence of blue or ultraviolet light is sensitive to the earth's
>> magnetic field. Some birds are much more sensitive than others. Many
>> birds also have small magnetic particles in their olfactory lobes, and
>> seem to integrate the signals from their right eye with the signals
>> from the olfactory lobes. Strangely enough, they cannot detect
>> differences in the declination of the earth's magnetic field and
>> instead rely on the inclination and strength of the field instead.
http://www.ks.uiuc.edu/Research/cryptochrome/
Mac
<lay...@panix.nul> wrote:
>
>http://www.ks.uiuc.edu/Research/cryptochrome/
Isn't that kewl stuff (TM)? Basically, birds have a built-in heads-up
display of magnetic direction.
>
Lee Ayrton
Yes, but what I find just as Kewl is that people are able to figure this
stuff out in the lab.
Charles Wm. Dimmick
> rc...@panix.com (Pierre Jelenc) wrote:
>
>> And? That has zero bearing on rubbing a needle with a silk cloth! You
>> cannot charge metal by rubbing it.
>
> I think the point is to get a static charge on the silk cloth first. Being
> a lousy conductor, the silk can't transfer much of its charge to the metal.
> But moving the precharged silk across the metal creates a small magnetic
> field.
But as others have pointed out, the field will be 90 degrees off from
what you want.
Charles Wm. Dimmick
Charles
Don K
> Don K <d...@comcast.net> writes:
>> If I repeated the procedure using a metal clip to touch the doorknob,
>> there would still be a spark. Current would flow thru the metal clip to
>> whatever it touched.
>
> That's irrelevant. The current does not flow in the paperclip before you
> ground it.
It's relevant in that you had previously stated that static electricity
"does nothing to conductors, and nothing to magnetic domains".
It's my contention that it does. As I recall, if you touch an isolated conductor
to an electrostatically charged object1 (let's say it has excess electrons),
some of those excess electrons flow from object1 and distribute themselves
throughout the surface of the conductor until the potentials of the conductor
and the charged object1 have equalized.
That movement of electrons creates a magnetic field while it's happening.
Similarly, If you bring the charged conductor and object1 close to charged
object2, the repelling or attracting forces will cause the electrons on the surface
of the conductor to redistribute themselves.
That movement again creates a magnetic field.
Then finally, and obviously, if you touch the conductor to object2, then
electrons will flow until the potentials are equalized and that current
again creates a magnetic field.
>
>> If the metal clip touches only object1, its voltage is the same
>> as object 1. If you then make it also touch object2, which is at a
>> different voltage, there will be current flowing thru the metal.
>
> And? That has zero bearing on rubbing a needle with a silk cloth! You
> cannot charge metal by rubbing it. A static electricity generator (e.g.
> Van de Graaff) works by rubbing two different, non-conducting surfaces
> together, and gathering the charge with a metal brush and into a
> capacitor. Or rubbing rubber soles against a wool carpet and gathering the
> charge into a capacitor made of a damp body with a paperclip, and a
> doorknob.
>
> Furthermore, even if there were a current, the magnetic field would be
> orthogonal to it, i.e. across the needle, not along it. The needle should
> then align east-west, with its *long* sides toward north and south.
The direction(s) of current flow and magnetic orientation would depend on
how the needle is held.
If the needle is lying flat on a charged object, electrons will redistribute
from the object, flowing from the bottom edge touching the object and
will distribute themselves along the furtherest top edge (being repelled
by the negative charge of the object).
In this case, that current flow could create a magnetic field aligned with
the needle.
Don
Pierre Jelenc
> "Pierre Jelenc" <rc...@panix.com> wrote in message
> news:ifaj6r$mhq$1...@reader1.panix.com...
> > Don K <d...@comcast.net> writes:
> >> If I repeated the procedure using a metal clip to touch the doorknob,
> >> there would still be a spark. Current would flow thru the metal clip to
> >> whatever it touched.
> >
> > That's irrelevant. The current does not flow in the paperclip before you
> > ground it.
>
> It's relevant in that you had previously stated that static electricity
> "does nothing to conductors, and nothing to magnetic domains".
When it flows, it's not static anymore. If you want to charge a conductor
with static electricity in order to later discharge it and produce a
current, you cannot do it by rubbing the conductor with silk or anything
like it, you need to use a static electricity machine, which rubs two NON-
conductors against each other and collects the electrons with a brush-like
collector. Then, when you ground it, current will flow; but it's not
static anymore.
> That movement of electrons creates a magnetic field while it's happening.
At right angle to the current.
> If the needle is lying flat on a charged object, electrons will redistribute
> from the object, flowing from the bottom edge touching the object and
> will distribute themselves along the furtherest top edge (being repelled
> by the negative charge of the object).
>
> In this case, that current flow could create a magnetic field aligned with
> the needle.
That is not the scenario proposed to the lost boy-scout with his silk
underwear.
Let's say that, as you rub a needle from eye to point, a molecule of silk
tears off an electron from an iron atom. As that charged molecule slides
further, the electron is immediately pulled back by the metal, because
conductors have --by definition-- a large conduction band that transmits
the positive charge left behind toward the excess negative charge.
In contrast, with two non-conductors (as is the case of an electrostatic
generator, or of hair and an acrylic sweater) the only way for an electron
to be captured back is if it were to pass just right above a positive hole
left behind by a prior lost electron, which is not very likely at the
molecular level. With the needle, the only electron that would not be
recaptured would be the one on the last atom of metal just as the cloth is
pulled off the needle. One single electron per pass, hoping it's not
recaptured on the next pass.
K_S_ONeill
Single Electron Hoping is an excellent band name.
groo
Why not rub it 90 degrees off the lengthwise axis?
Hieronymus Agricola
(in article <Xns9E5CC60E2B47794...@81.169.183.62>):
>
> Why not rub it 90 degrees off the lengthwise axis?
>
Perv!
Hactar
It's small enough that it doesn't appear in most "personals" sections.
--
I firmly believed we should not march into Baghdad ...To occupy Iraq
would instantly shatter our coalition, turning the whole Arab world
against us and make ... a latter-day Arab hero assigning young soldiers
to a fruitless hunt for a securely entrenched dictator[.] -- GHWB
Don K
> Don K <d...@comcast.net> writes:
>> "Pierre Jelenc" <rc...@panix.com> wrote in message
>> news:ifaj6r$mhq$1...@reader1.panix.com...
>> > Don K <d...@comcast.net> writes:
>> >> If I repeated the procedure using a metal clip to touch the doorknob,
>> >> there would still be a spark. Current would flow thru the metal clip to
>> >> whatever it touched.
>> >
>> > That's irrelevant. The current does not flow in the paperclip before you
>> > ground it.
>>
>> It's relevant in that you had previously stated that static electricity
>> "does nothing to conductors, and nothing to magnetic domains".
>
> When it flows, it's not static anymore.
OK, now I see the problem has been a failure to communicate.
You basically said the compass procedure was bogus and gave
your reasons...
whereas I was taking issue over semantics within your reasons and
was basically ignoring the validity of the compass procedure.
Static electricity generally refers to an accumulation of electrical charge
on an object, not a state of absolute stillness.
Electricity and static electricity aren't two separate states of being
that electrons switch into and out of.
Almost nothing we commonly encounter and characterize as static electricity
would meet your narrow interpretation because those things are never really static.
There is nearly always some leakage current flowing that will eventually reduce
a charge down to zero if you wait long enough.
That said, I think I agree with you now that compass procedure is probably
bogus.
Don
Don K
> Don K <d...@comcast.net> writes:
>> "Pierre Jelenc" <rc...@panix.com> wrote in message
>> news:ifaj6r$mhq$1...@reader1.panix.com...
>> > Don K <d...@comcast.net> writes:
>> >> If I repeated the procedure using a metal clip to touch the doorknob,
>> >> there would still be a spark. Current would flow thru the metal clip to
>> >> whatever it touched.
>> >
>> > That's irrelevant. The current does not flow in the paperclip before you
>> > ground it.
>>
>> It's relevant in that you had previously stated that static electricity
>> "does nothing to conductors, and nothing to magnetic domains".
>
> When it flows, it's not static anymore.
OK, now I see the problem has been a failure to communicate.
Bill Kinkaid
wrote:
>In article <59c9ca86-405a-4b84...@z19g2000yqb.googlegroups.com>,
>K_S_ONeill <uan...@gmail.com> wrote:
>> On Dec 28, 3:21 pm, r...@panix.com (Pierre Jelenc) wrote:
>> >
>> > In contrast, with two non-conductors (as is the case of an electrostatic
>> > generator, or of hair and an acrylic sweater) the only way for an electron
>> > to be captured back is if it were to pass just right above a positive hole
>> > left behind by a prior lost electron, which is not very likely at the
>> > molecular level. With the needle, the only electron that would not be
>> > recaptured would be the one on the last atom of metal just as the cloth is
>> > pulled off the needle. One single electron per pass, hoping it's not
>> > recaptured on the next pass.
>>
>> Single Electron Hoping is an excellent band name.
>
>It's small enough that it doesn't appear in most "personals" sections.
Just a little atom of Chlorine, valence minus one
Swimming through the sea, digging the scene, just having fun
She’s not worried about the shape or size of her outside shell
It’s fun to ionize
Just an atom of Cl with an unfilled shell
Somewhere in that sea lurks handsome Sodium
With enough electrons on his outside shell plus that extra one
Somewhere in this deep blue sea there’s a negative
For my extra energy
Yes, somewhere in this foam my positive will find a home
Then unsuspecting Chlorine felt a magnetic pull
She looked down and her outside shell was full
Sodium cried, “What a gas, be my bride
And I’ll change your name from Chlorine to Chloride”
Now the sea evaporates to make the clouds for the rain and snow
Leaving her chemical compounds in the absence of H2O
But the crystals that wash upon the shore are happy ones
So if you never thought before
Think of the love that you eat when you salt your meat
- Kate and Anna McGarrigle, NaCl
--
Bill in Vancouver
Lee Ayrton
Yup, I was just responding to the accusation of Lesoidal shaggydogism.
S. Checker
> woods you should take along a deck of cards. If you get lost, then break
> open the pack and start playing solitaire. Within 20-30 minutes some
> idiot will come along and start kibitzing your play.
In another place we were taught that you should simply bury a short
length of fibre optic cable, then ride the backhoe that cuts it back
to civilization.
--
... ich bin in einem dusenjet ins jahr 53 vor chr ... ich lande im
antiken Rom ... einige gladiatoren spielen scrabble ... ich rieche
PIZZA ...
groo
Fortunately, I will sell you one in 17 years. Please remit $100K
immediately to cover the $1.3M I will charge you for it then.
--
"...which is exactly what you're saying except the opposite." - NJM, afca
S. Checker
> Lee Ayrton <lay...@panix.nul> wrote:
>
>> On Mon, 27 Dec 2010 09:58:34 -0800, Bob wrote:
>>
>>>> >> > produced with various materials; is it not forgiving enough to
>>>> >> > use powdered Tide?
>>>>
>>>> >> Needs phosphates, doesn't it?
>>>>
>>>> > It doesn't.
>>>>
>>>> shaddup now.
>>>
>>> Not soon enough. That doesn't have nitrite, either.
>>
>> Dang. now I need a time machine.
>>
>>
>
> Fortunately, I will sell you one in 17 years. Please remit $100K
> immediately to cover the $1.3M I will charge you for it then.
Here's $10. Invest it in IBM in 1936 and pay me the difference now.
--
Rule 1: Spammers lie.
groo
I won't invent the time machine for another 17 years, and I need money now
to cover the development cost.
Don K
news:Xns9E5D893F8B03B94...@188.40.43.230...
I shouldn't be telling you this, but you will need to take a ball of twine,
a wallet photo of Idi Amin, and a kazoo with you when you first try it out.
Don
Bill Turlock
Ya gotta admit it was a primary candidate.
Greg Goss
>"groo" <afca...@gmail.com> wrote
>> I won't invent the time machine for another 17 years, and I need money now
>> to cover the development cost.
>
>I shouldn't be telling you this, but you will need to take a ball of twine,
>a wallet photo of Idi Amin, and a kazoo with you when you first try it out.
Should we tell him to make sure it's natural twine? Some of the best
hero literature was written in the aftermath in the alpha-green family
of timelines when he showed up with polypropylene.
--
Tomorrow is today already.
Greg Goss, 1989-01-27
Charles Wm. Dimmick
Anyway, in a book I was reading last night I learned that when you
magnetize a needle or any other relatively long piece of magnetizable
material the new permanent magnetic field will ALWAYS line up along the
long axis, no matter what the alignment of the inducing field. Something
to do with "easy" directions and "hard" directions of magnetization. For
those who want to read more, try:
http://www.irm.umn.edu/hg2m/hg2m_c/hg2m_c.html
and slide down to "shape anisotropy".
Charles
groo
That is for grain shapes, not macroscopic object shapes. I don't know what
the grain shapes in a needle normally are like. Are needles cold rolled?
Hactar
Drawn to make wire, then tempered or whatever they do to make blades
hard.
--
-eben QebWe...@vTerYizUonI.nOetP royalty.mine.nu:81
He who will not reason is a bigot; he who cannot is a fool;
and he who dares not is a slave. -Sir William Drummond
Charles Wm. Dimmick
Doesn't matter. Because of the influence of other domains bordering each
magnetic domain the rule still applies macroscopically. Because there
are many more domains on each side of a particular domain going along
the axis of the needle than there are domains on either side going
across the minimum diameter the axial direction becomes the "easy"
direction for a magnetic field and thus becomes preferred. No, I don't
quite understand it either. By the way, most grains are too large to
contain a single magnetic domain, and it is the statistical majority of
domain fields that determines the overall magnetic field of an object,
not the shapes of the grains.
Charles
jeff_wisnia
> In article <Z-adnc26D5pHB4vQ...@giganews.com>,
> jeff_wisnia <jwisnia...@conversent.net> wrote:
>
>>
>>I just watched the movie "The Edge" on Netflix and thought it odd that
>>the central character magnetized a paperclip to make a floating compass
>>by rubbing it on his silk shirt cuff.
>>
>>I've shown my kids a floating compass after magnetizing a sewing needle
>>by sliding it against a rare earth magnet, but agsinst silk, I think not.
>>
>>I'm aware you can magnetize a steel rod by holding it in one orientation
>>and repeatedly whacking it with a hammer, but rubbing steel on silk
>>strikes me as BS.
>>
>>Am I correct, and was that just a bit of artistic license for thast movie?
>
>
> It sounds like someone was confusing magnetism with electrostatics.
>
> It seems like certain metal forming processes leave parts magnetized
> whether you want them to be or not, but I don't recall if paperclips
> were among them. Try straightening one out, and see if it acts like
> a weak compass needle on its own.
>
>
I'm pretty sure I've now satisfied myself that the silk rubbing trick is
pure bullshit.
I grabbed two needles from SWMBO's sewing kit an straightened out a
paperclip from the supply on my desk.
when floated on water on a slice of cork they all aligned north/south,
indicating that they were already magnetized.
I demagnetized all of them by passing them between the AC current
carrying rods of a turned on 250 watt Weller soldering gun.
When floated on the cork they all showed no evidence of wanting to
rotate to a north-south alignment. When moved to a new resting position
they just stayed there.
I rubbed all of them vigorously with silk which made no change to their
ability to seek alignment with the earth's field.
I remagnetized all three by rubbing them on a rare earth magnet and they
behaved as compass needles again.
Case closed as far as I'm concerned. I've offered that information to
the IMDB's page for "The Edge", the movie that got me to start this
thread a few days ago.
Jeff
--
Jeffry Wisnia
(W1BSV + Brass Rat '57 EE)
The speed of light is 1.8*10e12 furlongs per fortnight.
groo
> I rubbed all of them vigorously with silk which made no change to their
> ability to seek alignment with the earth's field.
>
That won't work. Silk is triboelectric, but the needles aren't, and you
don't want to put an electric charge on them anyway. You need to precharge
the silk by rubbing it against something else (cat fur?). Then try to
magnetize the needles with the charged silk. It should work, unless the
charge doesn't stay on the silk. And you don't want to rub "vigorously",
you want to drag the silk across the needles, always in the same direction
(not back and forth). You might need to wear insulating gloves so that the
silk doesn't discharge through you.
Alan J
> jeff_wisnia <jwisniaDu...@conversent.net> wrote:
>
>> I rubbed all of them vigorously with silk which made no change to
>> their
>> ability to seek alignment with the earth's field.
>>
>
> That won't work. Silk is triboelectric, but the needles aren't, and
> you
> don't want to put an electric charge on them anyway. You need to
> precharge
> the silk by rubbing it against something else (cat fur?). Then try to
> magnetize the needles with the charged silk. It should work, unless
> the
> charge doesn't stay on the silk. And you don't want to rub
> "vigorously",
> you want to drag the silk across the needles, always in the same
> direction
> (not back and forth). You might need to wear insulating gloves so that
> the
> silk doesn't discharge through you.
I don't believe anyone can magnetise needles via static electricity [1].
You can easily get high voltages (as I know from repeated painful
experience) but the current is negligible. If it wasn't, it would kill
you. Watts = V * A, and how much energy would rubbing a needle on silk
generate anyway? A few milliwatts?
Think about it like water: voltage is the pressure and current the
volume of electrons. You can no more generate a decent magnetic field
from static electricity than you can turn a waterwheel by firing a
high-powered water pistol at it.
--
Alan
1. I exclude lightning, which is static, and generates high amperages
and voltages.
Don K
news:iftoeq$mh7$1...@news.eternal-september.org...
> "groo" <afca...@gmail.com> wrote in message
> news:Xns9E6297DBA24D494...@188.40.43.213...
>> jeff_wisnia <jwisniaDu...@conversent.net> wrote:
>>
>>> I rubbed all of them vigorously with silk which made no change to their
>>> ability to seek alignment with the earth's field.
>>>
>>
>> That won't work. Silk is triboelectric, but the needles aren't, and you
>> don't want to put an electric charge on them anyway. You need to precharge
>> the silk by rubbing it against something else (cat fur?). Then try to
>> magnetize the needles with the charged silk. It should work, unless the
>> charge doesn't stay on the silk. And you don't want to rub "vigorously",
>> you want to drag the silk across the needles, always in the same direction
>> (not back and forth). You might need to wear insulating gloves so that the
>> silk doesn't discharge through you.
>
>
> I don't believe anyone can magnetise needles via static electricity [1]. You can easily
> get high voltages (as I know from repeated painful experience) but the current is
> negligible. If it wasn't, it would kill you. Watts = V * A, and how much energy would
> rubbing a needle on silk generate anyway? A few milliwatts?
The real question is how much energy does it take to sufficiently magnetize
a small needle enough that it seeks alignment with the earth's magnetic field.
I don't know that answer, do you?
> Think about it like water: voltage is the pressure and current the volume of electrons.
> You can no more generate a decent magnetic field from static electricity than you can
> turn a waterwheel by firing a high-powered water pistol at it.
We don't know whether that water pistol has to spin a pinwheel or a
Niagara Falls Turbine.
Don
Alan J
news:iftr4m$4on$1...@news.eternal-september.org...
No, I don't either.
How much energy would rubbing something on silk generate though? Not a
lot. Microwatts, probably. Then you would have the loss through
conversion from electricity to magnetism.
>> Think about it like water: voltage is the pressure and current the
>> volume of electrons. You can no more generate a decent magnetic field
>> from static electricity than you can turn a waterwheel by firing a
>> high-powered water pistol at it.
>
> We don't know whether that water pistol has to spin a pinwheel or a
> Niagara Falls Turbine.
Maybe that was a bad analogy. OK, the electrostatic charge on the needle
has the power to raise up a piece of gold leaf, several atoms thick, on
an electroscope. How much energy can we hope to extract from that? Not a
lot, IMO. Not enough to do serious work, like magnetising something.
I agree with Jeff Wisnia's experimental results.
--
Alan
groo
> I don't believe anyone can magnetise needles via static electricity [1].
> You can easily get high voltages (as I know from repeated painful
> experience) but the current is negligible. If it wasn't, it would kill
> you. Watts = V * A, and how much energy would rubbing a needle on silk
> generate anyway? A few milliwatts?
>
Current flow isn't the goal; it is the anti-goal. The idea is to leave the
charge on the silk and move it, thus inducing a magnetic field. The
majority of the work should be done by the mechanical motion, not from the
energy of the charge itself.
Alan J
> "Alan J" <not...@dontuse.invalid> wrote:
>
>> I don't believe anyone can magnetise needles via static electricity
>> [1].
>> You can easily get high voltages (as I know from repeated painful
>> experience) but the current is negligible. If it wasn't, it would
>> kill
>> you. Watts = V * A, and how much energy would rubbing a needle on
>> silk
>> generate anyway? A few milliwatts?
>>
>
> Current flow isn't the goal; it is the anti-goal. The idea is to
> leave the
> charge on the silk and move it, thus inducing a magnetic field. The
> majority of the work should be done by the mechanical motion, not from
> the
> energy of the charge itself.
I think I see what you're getting at. Does the static need to be
*prevented* from discharging down the needle, then? If the person is
holding the needle in un-insulated fingers, then the needle is more or
less earthed. You mentioned this point earlier, but it was to do with
not losing the charge off the silk. Should the person improvise
insulated gloves?
--
Alan
groo
Yes. Bleeding the charge off the silk would be counterproductive. You
need a moving charge to generate a magnetic field. Less charge, less
field.
In most circumstances, that "moving charge" is accomplished with an
electric current. But I'm pretty sure that Maxwell's equations don't
require that.
jeff_wisnia
Near the bottom of the third page on the site referenced by D.F. Manno
in his reply to my OP, the author of that page says he was able to
magnetize needles by letting a static spark discharge from his body flow
through a small coil surrounding the needle:
http://wildwoodsurvival.com/survival/navigation/rbimprovisedcompass03.html
Now, that I can believe.
Don K
news:ig2rf4$7pa$1...@news.eternal-september.org...
Using a coil as described, that experiment certainly has enough documentation
to be credibly repeatable.
The human body charge can be modeled as a 100pF capacitor,
charged to 2000V, and discharging thru 1500 Ohm.
http://en.wikipedia.org/wiki/Human_body_model
I'm wondering whether the electrostatic procedure can be redesigned to do
away with the coil, and still work.
Don