| Topic: |
Science > Physics |
| User: |
"Allan Adler" |
| Date: |
21 Jan 2008 09:47:12 AM |
| Object: |
Franck-Hertz experiment |
I'd like to read the original articles on the Franck-Hertz experiment.
Are they available online or are they reproduced in a modern book? I'm
interested in them partly because I like to read original sources and
partly because I'm not sure that modern treatments of the experiment,
such as in Melissinos' book, provide enough information about how the
experiment was originally done. For example, I would guess that Franck
and Hertz probably didn't use a specially made tube from Leybold whose
specs, in the style of the RCA receiving tube manual, are hard to find.
And maybe their tube wasn't even a tetrode. And they probably didn't
use a Keithley electrometer.
Also, Melissinos says that one can, in principle, observe the first excitation
optically, even though an examination of the electron beam contains more
precise information. No reference is given to whether anyone ever published
details and results of a version of the experiment which used the optical
method. For all I know, that might be the way Franck and Hertz originally
did it.
--
Ignorantly,
Allan Adler <ara@zurich.csail.mit.edu>
* Disclaimer: I am a guest and *not* a member of the MIT CSAIL. My actions and
* comments do not reflect in any way on MIT. Also, I am nowhere near Boston.
.
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| User: "Szczepan Białek" |
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| Title: Re: Franck-Hertz experiment |
22 Jan 2008 09:45:51 AM |
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"Allan Adler" <ara@nestle.csail.mit.edu> wrote
news:y93ejcbkwov.fsf@nestle.csail.mit.edu...
I'd like to read the original articles on the Franck-Hertz experiment.
Are they available online or are they reproduced in a modern book? I'm
interested in them partly because I like to read original sources and
partly because I'm not sure that modern treatments of the experiment,
such as in Melissinos' book, provide enough information about how the
experiment was originally done. For example, I would guess that Franck
and Hertz probably didn't use a specially made tube from Leybold whose
specs, in the style of the RCA receiving tube manual, are hard to find.
And maybe their tube wasn't even a tetrode. And they probably didn't
use a Keithley electrometer.
Also, Melissinos says that one can, in principle, observe the first
excitation
optically, even though an examination of the electron beam contains more
precise information. No reference is given to whether anyone ever
published
details and results of a version of the experiment which used the optical
method. For all I know, that might be the way Franck and Hertz originally
did it.
"Early experiments to solve the riddle of electricity often included the use
of anode-cathode tubes (glass tubes that contained an anode at one end and a
cathode at the other). When most of the air was evacuated from the tube, an
electrical charge could be seen jumping across the gap between the two
electrodes. It was English physician and chemist Michael Faraday (1791-1867)
who noticed that as the amount of air in the tube decreased, a faint glow
between the electrodes could be seen". - It is from:
http://www.discoveriesinmedicine.com/Bar-Cod/Cathode-Ray-Tube-CRT.html
They used rather high voltage so they have seen optical patern similar to
that in Franck and Hertz at higher voltages.
Here is similar experiment with a noble gas:
http://www.hep.wisc.edu/~prepost/407/ramsauer/ramsauer.pdf
S*
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| User: "Szczepan Białek" |
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| Title: Re: Franck-Hertz experiment |
22 Jan 2008 02:53:05 PM |
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"Szczepan Białek" <sz.bialek@wp.pl> wrote
news:fn52ic$j77$1@node1.news.atman.pl...
"Allan Adler" <ara@nestle.csail.mit.edu> wrote
news:y93ejcbkwov.fsf@nestle.csail.mit.edu...
"Early experiments to solve the riddle of electricity often included the
use of anode-cathode tubes (glass tubes that contained an anode at one end
and a cathode at the other). When most of the air was evacuated from the
tube, an electrical charge could be seen jumping across the gap between
the two electrodes. It was English physician and chemist Michael Faraday
(1791-1867) who noticed that as the amount of air in the tube decreased, a
faint glow between the electrodes could be seen". - It is from:
http://www.discoveriesinmedicine.com/Bar-Cod/Cathode-Ray-Tube-CRT.html
They used rather high voltage so they have seen optical patern similar to
that in Franck and Hertz at higher voltages.
Here are the optical paterns:
http://members.chello.nl/h.dijkstra19/big/crookes/narva%20cross%20scale.gif
It is from: http://members.chello.nl/~h.dijkstra19/page7.html
S*
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| User: "Allan Adler" |
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| Title: Re: Franck-Hertz experiment |
23 Jan 2008 01:35:46 AM |
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"Szczepan Białek" <sz.bialek@wp.pl> writes:
"Szczepan Białek" <sz.bialek@wp.pl> wrote
news:fn52ic$j77$1@node1.news.atman.pl...
news:y93ejcbkwov.fsf@nestle.csail.mit.edu...
"Early experiments to solve the riddle of electricity often included the
use of anode-cathode tubes (glass tubes that contained an anode at one end
and a cathode at the other). When most of the air was evacuated from the
tube, an electrical charge could be seen jumping across the gap between
the two electrodes. It was English physician and chemist Michael Faraday
(1791-1867) who noticed that as the amount of air in the tube decreased, a
faint glow between the electrodes could be seen". - It is from:
http://www.discoveriesinmedicine.com/Bar-Cod/Cathode-Ray-Tube-CRT.html
They used rather high voltage so they have seen optical patern similar to
that in Franck and Hertz at higher voltages.
Here are the optical paterns:
http://members.chello.nl/h.dijkstra19/big/crookes/narva%20cross%20scale.gif
It is from: http://members.chello.nl/~h.dijkstra19/page7.html
Thanks for this and your other reply. Let's see if I understand how this
answers my question. If you have a tube with some noble gas in it, you get
the nice coloring under high voltage. I thought that this was always due to
ionization, as in neon signs in store windows, whereas Franck-Hertz tubes
just cause some of the gas atoms to reach their first excited state. Still,
when they decay to the ground state, some light has to be emitted. So, I'll
have to look up the frequency of the light and check that it is visible light.
I thought Franck and Hertz used a Hg vapor tube, so I'll have to check the
frequency for Hg also. Even if it is ultraviolet, that can be detected
via fluorescence. Getting a different color from the color of the fully
ionized gas would show something different is happening, and if the atoms
are not deflected by a magnetic field, that would show it isn't due to
motion of ions.
In that case, it seems the Franck-Hertz experiment could even be done in this
qualitative way using a gas filled diode.
How does that sound?
--
Ignorantly,
Allan Adler <ara@zurich.csail.mit.edu>
* Disclaimer: I am a guest and *not* a member of the MIT CSAIL. My actions and
* comments do not reflect in any way on MIT. Also, I am nowhere near Boston.
.
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| User: "Szczepan Białek" |
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| Title: Re: Franck-Hertz experiment |
23 Jan 2008 04:20:29 AM |
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"Allan Adler" <ara@nestle.csail.mit.edu> wrote
news:y931w89c7u5.fsf@nestle.csail.mit.edu...
"Szczepan Białek" <sz.bialek@wp.pl> writes:
Here are the optical paterns:
http://members.chello.nl/h.dijkstra19/big/crookes/narva%20cross%20scale.gif
It is from: http://members.chello.nl/~h.dijkstra19/page7.html
Thanks for this and your other reply. Let's see if I understand how this
answers my question. If you have a tube with some noble gas in it, you get
the nice coloring under high voltage. I thought that this was always due
to
ionization, as in neon signs in store windows, whereas Franck-Hertz tubes
just cause some of the gas atoms to reach their first excited state.
Still,
when they decay to the ground state, some light has to be emitted. So,
I'll
have to look up the frequency of the light and check that it is visible
light.
In such tubes are ions and electrons which have different speeds. So the
collision are different.
I thought Franck and Hertz used a Hg vapor tube, so I'll have to check the
frequency for Hg also. Even if it is ultraviolet, that can be detected
via fluorescence.
Mercury vapor emits visible light also but mainly UV.
Getting a different color from the color of the fully
ionized gas would show something different is happening, and if the atoms
are not deflected by a magnetic field, that would show it isn't due to
motion of ions.
Color and pattern are the pressure and voltage dependent (This phenomena is
extensively researched by people like Hittorf
and De La Rue.)
.. Experiment is for ever (if confirmed by all) - explanation my be
different.
In that case, it seems the Franck-Hertz experiment could even be done in
this
qualitative way using a gas filled diode.
Yes. But qualitive effects can be seen in the Franck-Hertz experiment also.
In such tube are two diodes with one common anode in form of a grid.
How does that sound?
I am not an expert.
S*
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| User: "Allan Adler" |
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| Title: Re: Franck-Hertz experiment |
24 Jan 2008 08:52:30 PM |
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"Szczepan Białek" <sz.bialek@wp.pl> writes:
"Allan Adler" <ara@nestle.csail.mit.edu> wrote
news:y931w89c7u5.fsf@nestle.csail.mit.edu...
Thanks for this and your other reply. Let's see if I understand how this
answers my question. If you have a tube with some noble gas in it, you get
the nice coloring under high voltage. I thought that this was always due
to ionization, as in neon signs in store windows, whereas Franck-Hertz
tubes just cause some of the gas atoms to reach their first excited state.
Still, when they decay to the ground state, some light has to be emitted.
So, I'll have to look up the frequency of the light and check that it is
visible light.
In such tubes are ions and electrons which have different speeds. So the
collision are different.
I looked at the CRC Handbook. If I read the table correctly, which is not
guaranteed, the longest wavelengths listed for Hg vapor, Ne and Xe is around
3 to 4 microns. But that could just be the difference of two excited states.
Maybe the lowest energy excited state decays to ground state with visible
light, for all I know. The table doesn't make that clear. I'll keep looking.
Getting a different color from the color of the fully
ionized gas would show something different is happening, and if the atoms
are not deflected by a magnetic field, that would show it isn't due to
motion of ions.
Color and pattern are the pressure and voltage dependent (This phenomena is
extensively researched by people like Hittorf and De La Rue.) Experiment is
for ever (if confirmed by all) - explanation my be different.
It occurred to me that, conceivably, the deflection of the electrons by
the magnetic field could also cause the colored region to move. In that case,
more would have to be said to distinguish between the ionized case and the
excited case using a magnetic field.
In that case, it seems the Franck-Hertz experiment could even be done in
this qualitative way using a gas filled diode.
Yes. But qualitive effects can be seen in the Franck-Hertz experiment also.
In such tube are two diodes with one common anode in form of a grid.
By two diodes in one tube, do you mean a tube in which two diodes are
packaged? I haven't seen any written account of a Franck-Hertz experiment
using such a tube. Do you have a reference?
--
Ignorantly,
Allan Adler <ara@zurich.csail.mit.edu>
* Disclaimer: I am a guest and *not* a member of the MIT CSAIL. My actions and
* comments do not reflect in any way on MIT. Also, I am nowhere near Boston.
.
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| User: "Puppet_Sock" |
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| Title: Re: Franck-Hertz experiment |
23 Jan 2008 11:21:07 AM |
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On Jan 21, 10:47=A0am, Allan Adler <a...@nestle.csail.mit.edu> wrote:
I'd like to read the original articles on the Franck-Hertz experiment.
Are they available online or are they reproduced in a modern book?
[snip]
If you are unable to answer your own question, then how do
you expect to be able to understand the article if you do find
where it was published?
Seriously. Have you *heard* of a university library?
Have you heard of search engines?
Socks
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| User: "Allan Adler" |
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| Title: Re: Franck-Hertz experiment |
24 Jan 2008 08:39:47 PM |
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Smelly Sock <puppet_sock@hotmail.com> writes:
On Jan 21, 10:47=A0am, Allan Adler <a...@nestle.csail.mit.edu> wrote:
I'd like to read the original articles on the Franck-Hertz experiment.
Are they available online or are they reproduced in a modern book?
[snip]
If you are unable to answer your own question, then how do
you expect to be able to understand the article if you do find
where it was published?
The skills that go into locating a 19th century article in German and
the skills that go into reading it are quite different, moron. I'm
perfectly capable of reading the article.
Seriously. Have you *heard* of a university library?
Have you heard of search engines?
Socks
I have access to the journal. It is very old and shouldn't be photocopied.
There are microfilm versions but I have to pay to print them out. An online
version would be free and convenient, if it exists. I looked for one and
didn't find it. Others who are better at searching might find it easier to
locate it.
You must be the local misanthrope. Every group has at least one such parasite,
with nothing to contribute to any discussion except venom. I won't waste time
reading any of your postings in the future.
--
Ignorantly,
Allan Adler <ara@zurich.csail.mit.edu>
* Disclaimer: I am a guest and *not* a member of the MIT CSAIL. My actions and
* comments do not reflect in any way on MIT. Also, I am nowhere near Boston.
.
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| User: "Allan Adler" |
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| Title: Re: Franck-Hertz experiment |
25 Jan 2008 10:42:50 AM |
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Allan Adler <ara@nestle.csail.mit.edu> writes:
The skills that go into locating a 19th century article in German and
The Franck-Hertz article is 20th century. I'm also looking for some older
articles and for a moment lost track of which one I was writing about.
--
Ignorantly,
Allan Adler <ara@zurich.csail.mit.edu>
* Disclaimer: I am a guest and *not* a member of the MIT CSAIL. My actions and
* comments do not reflect in any way on MIT. Also, I am nowhere near Boston.
.
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| User: "Allan Adler" |
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| Title: Re: Franck-Hertz experiment |
31 Jan 2008 12:50:36 AM |
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(1) In the book of Melissinos and related application notes of Keithley on
the Franck-Hertz experiment, one is supposed to use an oven to heat the
tube. If you want to do this in the home and don't want to buy the Keithley
oven, what is it ok to use to heat the tube? The recommended temperature
is about 200 C, which one get even get in a toaster oven.
(2) Also, Melissinos tells you to use a copper-constantan thermocouple to
monitor the temperature of the tube. I don't have any experience doing
that on my own. I don't know where to buy one or how much it costs. I
don't know any simple experiments to do with just the thermocouple to
get practice using it.
(3) The RCA tube manual lists several tubes as being gas filled tubes but
doesn't say which ones are mercury vapor tubes. Which tubes, other than
the specially built Leybold tubes, are mercury vapor tetrodes that one
can still purchase from modern suppliers? I've located some vendors of
tubes but they don't have a list of mercury vapor tubes.
(4) Assuming one deciphers out Figures 1.5 and 1.7 of Melissinos on how to set
up the Franck-Hertz tube, Melissinos says the tube will produce nanoamps,
which one then has to measure. I don't know how to justify the assertion
about nanoamps based on any books I have about tubes. Also, I don't
presently have equipment to measure nanoamps; I don't even have a scope.
Probably, buying the Keithley 600A electrometer is an expensive way to do
it. I'm told that National Semiconductor has an op amp that can even
amplify femtoamps, the LMC6001. I haven't found a supplier for it yet and
don't know what it costs or what might be hard about using it. I've
downloaded the spec sheet and will try to make sense of it.
On the positive side, I'm getting better at writing assembly language
programs for the PC and expect that by the time I am able to do the
other things I described above, I'll also be able to interface the
experimental apparatus to the PC for control and data acquisition. But
I do need help with the other things.
Usually, when people do the FH experiment, someone has already solved all
the logistical problems related to it. Doing it in the home makes it necessary
to solve them myself and I'll need all the help I can get. In fact, I once
did the Franck-Hertz experiment in a university laboratory in a lab course
but that experience doesn't help me acquire the materials I need to set it
up on my own. Yes, I know Leybold sells the whole kit and kaboodle, but it
is expensive. There should be a dirt cheap way to do it.
--
Ignorantly,
Allan Adler <ara@zurich.csail.mit.edu>
* Disclaimer: I am a guest and *not* a member of the MIT CSAIL. My actions and
* comments do not reflect in any way on MIT. Also, I am nowhere near Boston.
.
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| User: "Eric Gisse" |
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| Title: Re: Franck-Hertz experiment |
31 Jan 2008 01:13:15 AM |
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On Jan 30, 9:50 pm, Allan Adler <a...@nestle.csail.mit.edu> wrote:
(1) In the book of Melissinos and related application notes of Keithley on
the Franck-Hertz experiment, one is supposed to use an oven to heat the
tube. If you want to do this in the home and don't want to buy the Keithley
oven, what is it ok to use to heat the tube? The recommended temperature
is about 200 C, which one get even get in a toaster oven.
200 C is 200 C, regardless of how you get there. However, the smaller
oven for the task is more regulated and can maintain the temperature
for the few minutes you require to take the measurements. How are you
going to do that in a kitchen oven?
All you need heated is the tube - you could probably pull it off by
putting the tube in a small pot and covering it. On the other hand - I
haven't the faintest idea of how consistent oven/stovetop temperatures
are. Do keep in mind that Mercury will be about and plan accordingly.
Like - never eat from that pot again.
(2) Also, Melissinos tells you to use a copper-constantan thermocouple to
monitor the temperature of the tube. I don't have any experience doing
that on my own. I don't know where to buy one or how much it costs. I
don't know any simple experiments to do with just the thermocouple to
get practice using it.
A thermocouple is just a fancy thermometer. The problem is that
thermometers that are sensitive to 200+ C are harder to find since
Mercury based thermometers are out of style these days.
(3) The RCA tube manual lists several tubes as being gas filled tubes but
doesn't say which ones are mercury vapor tubes. Which tubes, other than
the specially built Leybold tubes, are mercury vapor tetrodes that one
can still purchase from modern suppliers? I've located some vendors of
tubes but they don't have a list of mercury vapor tubes.
You could build the tube. On the other hand, the pre-built stuff is
Known Good...
(4) Assuming one deciphers out Figures 1.5 and 1.7 of Melissinos on how to set
up the Franck-Hertz tube, Melissinos says the tube will produce nanoamps,
which one then has to measure. I don't know how to justify the assertion
about nanoamps based on any books I have about tubes. Also, I don't
presently have equipment to measure nanoamps; I don't even have a scope.
In other words, it won't produce much current. But you aren't looking
for that - you are looking for voltage drops at the emission points
when the electrons successfully jump the potential gap.
You will need a scope or some other way of plotting the voltage vs
time.
Probably, buying the Keithley 600A electrometer is an expensive way to do
it. I'm told that National Semiconductor has an op amp that can even
amplify femtoamps, the LMC6001. I haven't found a supplier for it yet and
don't know what it costs or what might be hard about using it. I've
downloaded the spec sheet and will try to make sense of it.
You don't need femtoamps, just a good voltage source. But not so high
that you burn out the tube.
On the positive side, I'm getting better at writing assembly language
programs for the PC and expect that by the time I am able to do the
other things I described above, I'll also be able to interface the
experimental apparatus to the PC for control and data acquisition. But
I do need help with the other things.
Why do you need a PC for this?
Getting the PC to accept and process the data will be, imho, harder
than using a scope. Using the PC to _control_ the apparatus is just
silly.
Usually, when people do the FH experiment, someone has already solved all
the logistical problems related to it. Doing it in the home makes it necessary
to solve them myself and I'll need all the help I can get. In fact, I once
did the Franck-Hertz experiment in a university laboratory in a lab course
but that experience doesn't help me acquire the materials I need to set it
up on my own. Yes, I know Leybold sells the whole kit and kaboodle, but it
is expensive. There should be a dirt cheap way to do it.
"Cheap" is relative.
For this experiment, the term "kit" is rather loose as most of the
work is done by the oscilloscope and the plotter, which don't come
with the package :P . The only unique parts of the kit are the tube &
the control unit which is just a repackaged power supply that allows
you to ramp the voltage, which you could build yourself I'm sure.
The hard part will be obtaining the mercury vapor tube. In my
experience, Leybold stuff isn't cheap in either of the meanings of the
word. You have the original paper, and you have the wiring diagram, so
I don't imagine it'd be that hard to finangle something out of a test
tube. Just don't inhale too much Mercury vapor if you are fond of your
mental facilities.
BTW: Puppet isn't being a ***** just 'cuz. We get a lot of idiots on
here who intend to annoy for no purpose obvious to us or probably even
them.
--
Ignorantly,
Allan Adler <a...@zurich.csail.mit.edu>
* Disclaimer: I am a guest and *not* a member of the MIT CSAIL. My actions and
* comments do not reflect in any way on MIT. Also, I am nowhere near Boston.
.
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| User: "Puppet_Sock" |
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| Title: Re: Franck-Hertz experiment |
25 Jan 2008 11:48:33 AM |
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On Jan 25, 11:42=A0am, Allan Adler <a...@nestle.csail.mit.edu> wrote:
Allan Adler <a...@nestle.csail.mit.edu> writes:
The skills that go into locating a 19th century article in German and
The Franck-Hertz article is 20th century. I'm also looking for some older
articles and for a moment lost track of which one I was writing about.
So, you've already *got* the article, and are just annoying
people on purpose.
Fine.
Socks
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| User: "Allan Adler" |
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| Title: Re: Franck-Hertz experiment |
05 Feb 2008 11:35:51 PM |
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I've posted at http://swiss.csail.mit.edu/~adler/PHYSICS some of the
data that was collected about 20 years ago when I audited a lab course
in which we did the Franck-Hertz experiment. If anyone is interested in
taking a look at it, and maybe in making some sense of it, I'll be
interested in what they come up with.
--
Ignorantly,
Allan Adler <a...@zurich.csail.mit.edu>
* Disclaimer: I am a guest and *not* a member of the MIT CSAIL. My actions and
* comments do not reflect in any way on MIT. Also, I am nowhere near Boston.
.
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| User: "Eric Gisse" |
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| Title: Re: Franck-Hertz experiment |
31 Jan 2008 12:54:48 AM |
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On Jan 24, 5:39 pm, Allan Adler <a...@nestle.csail.mit.edu> wrote:
Smelly Sock <puppet_s...@hotmail.com> writes:
On Jan 21, 10:47=A0am, Allan Adler <a...@nestle.csail.mit.edu> wrote:
I'd like to read the original articles on the Franck-Hertz experiment.
Are they available online or are they reproduced in a modern book?
[snip]
If you are unable to answer your own question, then how do
you expect to be able to understand the article if you do find
where it was published?
The skills that go into locating a 19th century article in German and
the skills that go into reading it are quite different, moron. I'm
perfectly capable of reading the article.
Seriously. Have you *heard* of a university library?
Have you heard of search engines?
Socks
I have access to the journal. It is very old and shouldn't be photocopied.
There are microfilm versions but I have to pay to print them out. An online
version would be free and convenient, if it exists. I looked for one and
didn't find it. Others who are better at searching might find it easier to
locate it.
Digital camera.
You must be the local misanthrope. Every group has at least one such parasite,
with nothing to contribute to any discussion except venom. I won't waste time
reading any of your postings in the future.
--
Ignorantly,
Allan Adler <a...@zurich.csail.mit.edu>
* Disclaimer: I am a guest and *not* a member of the MIT CSAIL. My actions and
* comments do not reflect in any way on MIT. Also, I am nowhere near Boston.
.
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