Dear Sirs,

I did an experiment to measure the field due to a solenoid to see if it
varies across a diameter.

I constucted a solenoid of 4 turns of 16 guage wire 25 cm in diameter and 25
cm long. I found that the field was constant across the diameter.

This is entirely consistant with Gauss and does not support my calculations
based on the Biot-Savart construction.

See:
http://www.chrisweb.pwp.blueyonder.c...20solenoid.htm

Chris:
http://www.chrisscrazyideas.co.uk/

This would imply that a solenoid cannot be used for containment.

If I had been allowed, by teachers to carry out this experiment, thirty
years of my life would have been better spent.

Thank you.

I suggest that this demonstration is added to school science lessons in case
any one else falls into the same trap.

Brianwashing is not the way to teach children - proove your point with a
realistic and correctly carried out experiment.
Chris. Strevens.
"Chris" wrote in message
...
Dear Sirs,

I did an experiment to measure the field due to a solenoid to see if it
varies across a diameter.

I constucted a solenoid of 4 turns of 16 guage wire 25 cm in diameter and
25
cm long. I found that the field was constant across the diameter.

This is entirely consistant with Gauss and does not support my
calculations
based on the Biot-Savart construction.

See:

http://www.chrisweb.pwp.blueyonder.c...20solenoid.htm

Chris:
http://www.chrisscrazyideas.co.uk/

Chris wrote:
Dear Sirs,

I did an experiment to measure the field due to a solenoid to see if it
varies across a diameter.

I constucted a solenoid of 4 turns of 16 guage wire 25 cm in diameter and 25
cm long. I found that the field was constant across the diameter.


You probably didn't measure it very carefully. That's a pretty coarse
and short soloenoid, which will have significant deviations from
uniformity.

This is entirely consistant with Gauss and does not support my calculations
based on the Biot-Savart construction.


Then you didn't do them correctly. The Biot Savart Law will always give
the right answer.

-Eric

See:
http://www.chrisweb.pwp.blueyonder.c...20solenoid.htm

Chris:
http://www.chrisscrazyideas.co.uk/

And also FYI, "simple" equations for the axial component of magnetic
field inside a solenoid:

http://www.netdenizen.com/emagnet/of...oidoffaxis.htm

The field is not uniform inside a solenoid. If it were so, designing
solenoids for Magnetic Resonance Imaging would be a trivial task.

Eric



On Thu, 18 Sep 2003 15:28:49 +0100, "Chris"
wrote:

Dear Sirs,

I did an experiment to measure the field due to a solenoid to see if it
varies across a diameter.

I constucted a solenoid of 4 turns of 16 guage wire 25 cm in diameter and 25
cm long. I found that the field was constant across the diameter.

This is entirely consistant with Gauss and does not support my calculations
based on the Biot-Savart construction.

See:
http://www.chrisweb.pwp.blueyonder.c...20solenoid.htm

Chris:
http://www.chrisscrazyideas.co.uk/

Eric.

Again, Thank you for your discussion. I was pleased to see the analytical
experssions for quatitities I attempted to calculate as a teenager. My
maths never went beyond 1 st year undergraduate. I had heard of some of
the formulas like Legandre polynomials and elliptic functions. I understand
the elliptic functions are like sin etc for circular functions but for
ellipses. I know a bit about hyperbolic functions like sinh but I have
forgotten the geometrical meaning.

We did hermite polynomials and the legandre polynomials and also cherbychev.
I believe these are solutions for differential equations involving
trancendetal functions where exact analytical functions cannot be found.
But too us they were just formulas - soon forgotten.

My calculation was entirely numeric and being re-assured that I was on the
right track even though I made some mistakes in the algebra and trig.

I have not found these mistakes so I will re-work my numerical analysis and
calculation.

Now that I am re-assured I can re-do the calculation, I had not seen the
expressions that your link pointed too. There the maths does look complex
but only involves elementary functions at the basic level once the formulas
are broken down to the base level. So I could calculate them, but I think
I'll try again with my finite analysis.

I have removed the incorrect calculation web page and now have an account of
my simple school experiment. This is obviously limited by the accuracy of
my measurements and really not at all accurate.

Thank you again for your help, I really appreciate it.


"Eric Dennison" wrote in message
...
And also FYI, "simple" equations for the axial component of magnetic
field inside a solenoid:

http://www.netdenizen.com/emagnet/of...oidoffaxis.htm

The field is not uniform inside a solenoid. If it were so, designing
solenoids for Magnetic Resonance Imaging would be a trivial task.

Eric



On Thu, 18 Sep 2003 15:28:49 +0100, "Chris"
wrote: