Date: Mon, 7 Feb 2005 18:49:32 -0800

Author: "Chuck"

Subject: RE: Measure Mag Field w/out Gauss meter

Post:

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Have some fun! Build a single cell motor and add another set of =
commutating
ring pickoffs further out on the shaft so that they are in contact with =
the
bare scraped wire for a brief period opposite that of the battery. hook =
up
your meter/scope to those leads to see the induced voltage of the loop
passing the magnet. Then can you rectify and isolate the output voltage =
so
that it can be fed back instead of the battery to run the motor? Think
conventional ferrite magnet for the motor side and an NdFeB (Neodymium =
Iron
Boron) rare earth magnet for the induction side. Properly controlled =
you
may be able to finally construct that perpetual motion machine.

=20

cheers,

chuck.=20

=20

=20

=20

-----Original Message-----
From: owner-tap-l@listproc.appstate.edu
[mailto:owner-tap-l@listproc.appstate.edu] On Behalf Of Stan Dodds
Sent: Monday, February 07, 2005 9:28 AM
To: tap-l@listproc.appstate.edu
Subject: Re: Measure Mag Field w/out Gauss meter

=20

A rotating coil was used to measure magnetic fields long before Hall =
effect
devices were practical.

Construct a coil small enough to fit into the gap of your magnet. Mount =
it
on a spinning shaft driven by a small motor, preferably AC synchronous =
so
you know the speed. Measure the induced voltage with an AC voltmeter. =
From
the magnitude of the induced voltage, the area of the coil and the =
number of
turns you can compute the field.=20

The tricky part is making the connection from the rotating shaft to the
voltmeter. This is done by wrapping a conducting ring around the shaft =
and
loosely pressing a piece of springy metal against the ring to make a =
sliding
contact. The voltmeter connects to the springy metal piece.

As part of their inquiry, you might suggest your students do a =
literature
search. I'm reasonably sure a lot of people have looked at the effect of
static fields on organisms. It's a lot more like real science to build =
on
the work of your predecessors rather than take off entirely on your own.

Good luck, and thanks for taking the time to get these students involved
with interesting science.

Stan

On Feb 7, 2005, at 10:19 AM, S Ryan wrote:

Hi all,
=20
I have a group in my Inquiry Science class (highschool) setting up an
inquiry regarding the effects of magnetic fields on living subjects =
(pill
bugs). The original question regards the long term exposure to the =
magnetic
field around powerlines.=20
=20
In lieu of power lines, they want to use permanent magnets of varying
strengths (which we have), but we have no gauss meter, and so apparently =
no
way of quantifying the mag field strength of our magnets.
=20
Any bright ideas?
=20
Samantha

Ms. Samantha Ryan
To teach is to touch a life forever, and leave one's fingerprints upon =
the
future.
Science Dept.
Williamstown,VT 05679

Do you Yahoo!?
Yahoo! Search presents - Jib Jab's 'Second Term'

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charset="us-ascii"
Content-Transfer-Encoding: quoted-printable

charset=3Dus-ascii">

style=3D'font-size:10.0pt;
font-family:Arial'>Have some fun!  Build a single cell motor and =
set of commutating ring pickoffs further out on the shaft so that they =
are in
contact with the bare scraped wire for a brief period opposite that of =
the
battery.  hook up your meter/scope to those leads to see the =
induced voltage of
the loop passing the magnet.  Then can you rectify and isolate the =
output
voltage so that it can be fed back instead of the battery to run the =
motor?  Think
conventional ferrite magnet for the motor side and an =
size=3D1 face=3DVerdana> style=3D'font-size:9.0pt;font-family:Verdana'>NdFeB
(Neodymium Iron Boron) rare earth magnet for the induction =
side…
Properly controlled you may be able to finally construct that perpetual =
motion
machine…

style=3D'font-size:9.0pt;
font-family:Verdana'>

style=3D'font-size:9.0pt;
font-family:Verdana'>cheers,

style=3D'font-size:9.0pt;
font-family:Verdana'>chuck…
face=3DArial> style=3D'font-size:10.0pt;font-family:Arial'>

style=3D'font-size:
10.0pt;font-family:Arial;color:navy'>

style=3D'font-size:
10.0pt;font-family:Arial;color:navy'>

style=3D'font-size:
10.0pt;font-family:Arial;color:navy'>

face=3DTahoma> style=3D'font-size:10.0pt;font-family:Tahoma'>-----Original =
Message-----

From:
owner-tap-l@listproc.appstate.edu =
[mailto:owner-tap-l@listproc.appstate.edu] style=3D'font-weight:bold'>On Behalf Of Stan Dodds

Sent: Monday, February =
07, 2005
9:28 AM

To: =
tap-l@listproc.appstate.edu

Subject: Re: Measure Mag =
Field
w/out Gauss meter

face=3D"Times New Roman"> style=3D'font-size:12.0pt'>

style=3D'margin-right:0in;margin-bottom:12.0pt;margin-left:
.5in'> style=3D'font-size:12.0pt'>A
rotating coil was used to measure magnetic fields long before Hall =
effect
devices were practical.

Construct a coil small enough to fit into the gap of your magnet. Mount =
it on a
spinning shaft driven by a small motor, preferably AC synchronous so you =
know
the speed. Measure the induced voltage with an AC voltmeter. From the =
magnitude
of the induced voltage, the area of the coil and the number of turns you =
can
compute the field.

The tricky part is making the connection from the rotating shaft to the
voltmeter. This is done by wrapping a conducting ring around the shaft =
and
loosely pressing a piece of springy metal against the ring to make a =
sliding
contact. The voltmeter connects to the springy metal piece.

As part of their inquiry, you might suggest your students do a =
literature
search. I'm reasonably sure a lot of people have looked at the effect of =
static
fields on organisms. It's a lot more like real science to build on the =
work of

Good luck, and thanks for taking the time to get these students involved =
with
interesting science.

Stan

On Feb 7, 2005, at 10:19 AM, S Ryan wrote:

face=3D"Times New Roman"> style=3D'font-size:12.0pt'>Hi all,

I have a group in my Inquiry =
Science class
(highschool) setting up an inquiry regarding the effects of magnetic =
fields on
living subjects (pill bugs).  The original question regards the =
long term
exposure to the magnetic field around powerlines.

Arial>

In lieu of power lines, they want to use permanent magnets of varying =
strengths
(which we have), but we have no gauss meter, and so apparently no way of
quantifying the mag field strength of our magnets.

Any bright ideas?

Samantha

6A6A,5A5A,CDCD> style=3D'font-weight:bold;font-style:italic'>Ms. Samantha =
Ryan

6A6A,5A5A,CDCD> style=3D'font-weight:bold;font-style:italic'>To teach is to touch a life =
forever,
and leave one's fingerprints upon the =
future.

0000,0000,BFBF>Science
Dept.

Roman>Williamstown,VT
05679

Do you Yahoo!?

Yahoo! Search presents - Jib Jab's =
'Second Term'

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From chuck.patten@verizon.net Mon Feb 7 21:47:26 2005

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