Date: Fri, 18 Feb 2011 13:22:05

Author: Michael Thomason

Subject: Re: Tin Foil Capacitor

Post:

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Here



http://physicslearning.colorado.edu/Website_new/Common/ViewDemonstration.asp
?Topic=5

&SubSubtopic=5C10.31&DemoCode=5C10.31



is my tin foil capacitor, manufactured by E B Benjamin, 1800-1914,



Michael Thomason, Director of Physics Learning Laboratories

University of Colorado Boulder Department of Physics

303-492-7117

thomason@colorado.edu

http://physicslearning.colorado.edu



From: tap-l-owner@lists.ncsu.edu [mailto:tap-l-owner@lists.ncsu.edu] On
Behalf Of Paul Nord
Sent: Thursday, February 17, 2011 8:19 PM
To: tap-l@lists.ncsu.edu
Cc: Paul Nord
Subject: Re: [tap-l] Tin Foil Capacitor



Bill,



It's the last paragraph of the article that has this error.

Here's the citation from December:

Tin foil capacitor



And if it's not bad form to quote the article here:

During the demo, students complete the right col- umn with
their actual observations and explanations. In addition, the sheet has
several concluding questions such as, "Why is it important that the tube in
this demo is made of plastic?"

It might be possible to make another tube that has the foil
sandwiched between sheets of plastic or paper and then roll up the foil. The
plastic should insulate the foil layers when it is rolled up, and therefore
there should be no difference in elec- troscope separation when the foil
sandwich is unrolled and rolled.



Tom - no reference to your article in the December issue. Here's a link to
your 1976 article:

19th century textbook illustrations
-VII. Surface charge
density

Great illustration!



Paul





On Feb 17, 2011, at 6:46 PM, William Beaty wrote:





On Thu, 17 Feb 2011, Paul Nord wrote:




that he has not tried this. Would a coil of a single foil with a insulating
layer have a higher capacitance than a conducting tube? Wouldn't the charge
simply move to the outside surface?


Yep, all foil parts are at the same potential, so there won't be e-fields
between the layers. Maybe he meant to use *two* foils to create a
capacitor, and ground one of them?

(((((((((((((((((( ( ( ( ( (O) ) ) ) ) )))))))))))))))))))
William J. Beaty http://staff.washington.edu/wbeaty/
beaty, chem washington edu Research Engineer
billb, amasci com UW Chem Dept, Bagley Hall RM74
206-543-6195 Box 351700, Seattle, WA 98195-1700




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He=
re h=
ttp://physicslearning.colorado.edu/Website_new/Common/ViewDemonstration.a=
sp?Topic=3D5&SubSubtopic=3D5C10.31&DemoCode=3D5C10.31 is=
my tin foil capacitor, manufactured by E B Benjamin, =
1800-1914, Mi=
chael Thomason, Director of Physics Learning =
Laboratories =
University of Colorado Boulder Department of =
Physics&n=
bsp; =
303-492-7117&n=
bsp; =
thomason@colorado.edu&n=
bsp; =
http://physicslearning.colorado.edu From:=
=
tap-l-owner@lists.ncsu.edu [mailto:tap-l-owner@lists.ncsu.edu] On =
Behalf Of Paul NordSent: Thursday, February 17, 2011 8:19 =
PMTo: tap-l@lists.ncsu.eduCc: Paul =
NordSubject: Re: [tap-l] Tin Foil =
Capacitor Bill, It's the last paragraph of the article that has this =
error.Here's the citation =
from December:Tin foil =
capacitor And if it's not bad form to quote the article =
here: &=
nbsp; =
During the demo, =
students complete the right col- umn with their actual observations and =
explanations. In addition, the sheet has several concluding questions =
such as, “Why is it important that the tube in this demo is made =
of plastic?” &=
nbsp; =
It might be =
possible to make another tube that has the foil sandwiched between =
sheets of plastic or paper and then roll up the foil. The plastic should =
insulate the foil layers when it is rolled up, and therefore there =
should be no difference in elec- troscope separation when the foil =
sandwich is unrolled and =
rolled. Tom - no reference to your article in the December =
issue. Here's a link to your 1976 =
article:19th =
century textbook illustrations—VII. Surface charge =
densityGreat =
illustration! Paul On =
Feb 17, 2011, at 6:46 PM, William Beaty wrote:On =
Thu, 17 Feb 2011, Paul Nord wrote:that he has not tried this. Would a coil of a =
single foil with a insulating layer have a higher capacitance than a =
conducting tube? Wouldn't the charge simply move to the outside =
surface?Yep, all foil parts are =
at the same potential, so there won't be e-fields between the layers. =
Maybe he meant to use *two* foils to create a capacitor, and =
ground one of them?(((((((((((((((((( ( ( ( ( =
(O) ) ) ) ) =
)))))))))))))))))))William J. Beaty =
&=
nbsp; http://staff.washington.edu/=
wbeaty/beaty, chem washington edu =
Research Engineerbillb, amasci com =
&=
nbsp; UW Chem Dept, Bagley Hall RM74206-543-6195 =
&=
nbsp; Box 351700, Seattle, WA =
98195-1700
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From tap-l-owner@lists.ncsu.edu Fri Feb 18 15:33:40 2011

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