Problem with the two slit experiment, Observing later

Hi laserlight,

Thanks for that... I sure hope it is right. It's a fight between the "good" effects of the Sun Solar Cycle and the "bad" swamping effects of Terrestrial Global Warming. Which influence is going to win? If the drought keeps up we will all be drinking mud in Brisbane with level 5 water restrictions. as long as we get rain this time we will have water recycling and desalination in full swing "next time".

Cheers

Just a preliminary report from the C2 optics research lab. I now have a laser. I decided peach brandy was a bad idea and invested in a box of red wine (about the same price) instead. My new laser (actually a laser levelling thing) has a fairly large spot size so by the time it's gone through a slit I can hardly see anything and I suspect I shall be able to see nothing at all if/when I get the second pair of slits organised. So far the only result has been a lot of stumbling about in complete darkness except for a red spot which seems to cause a certain amount of disorientation eg Where has the light switch gone? Also I seem to have become the newest (and probably oldest) member of a forum called HamsterHideout though this might have had more to do with the wine than the laser. This morning I have a headache - is this a common side effect of exposure to collimated light? More results (if any) to follow.
-C2.

C2- I should have told you, the DSE doesn't work unless you are drinking at
least 60 proof spirits. After a few glasses and your eyes have crossed, you see all
kinds of patterns. Just don't stare into the end of the laser!


LL

Hi Confused2, yquantum, Laserlight, fivedoughnut, "THEY", Montec, TRoc, Neil Farbstein, Aerohead et al,

Don't do anything unpleasant to your eyes. Making slits or decent pinholes is an "art". The other important factor is to have a good spatial filter to remove some of the source noise.

If we really want to know what may be happening in a slit or pinhole... they are secondary sources. I would be inclined to ask the question what happens inside the source and doing a really good job in this area requires some costly bits and pieces.

Here is a paper that I may have referenced before that does throw some light on the theoretical and the practical points that may be responsible for the divergence of sources. I think we can learn a bit about sources if we read about it rather than trying to duplicate it without a few bucks in our back pockets or the resources of a real Laboratory... no offense here but some of these optical results are a little "fiddlely" to set up. It is not worth half blinding yourself to simply duplicate what others with a zillion dollars and all the right equipment have already done...

The comments being made are quite interesting and the nature of that space near the source (and you would need to be able to connect the dots about a primary source and a secondary source) and come up with a theory in which this space around that 1/4 wavelength has on propagation. Distances can do strange things when light travels at infinite velocity. This all gets back to those discussions about Wheeler Feynman Absorber Theory. A consideration of effective refractive index is also relevant.
http://xxx.lanl.gov/ftp/physics/papers/0009/0009023.pdf
This is a recent reputable source of information and it may be "easier on the eyes" than the optical level.

Cheers

This post has been edited by Good Elf on Mar 20 2007, 04:59 PM

I really enjoyed your slit comment! Very funny!

C2, I too have tried to reproduce the DSE with a laser (thought it would be a good science project for they2) and didn't succeed. Didn't know alcohol needed to be used! That may have been my problem also... Wine is too low of a proof....... And I don't think "they"2's teacher would approve of vodka in the school for a science experiment......

If you succeed pm me so I can try to reproduce it for the kiddo. Her project deadline is rapidly coming.....

This is for TRoc and those who understand “music language”.

http://www.physicsjazz.info/applets/HarmonicSum.html
Physics and Music: Harmonic Sum Applet
---------------
http://www.mta.ca/faculty/arts-letters/mus...e09/page09.html
This is the summary to Pitch-Class Set Analysis. Don’t forget to look at the Table of pc set classes.
--------------------
"THEY"
Look at my summary. I'll post something that you might like for "THEY2".
jal

edit:
http://www.musicoftheprimes.com/index.htm
Music of the Primes


This post has been edited by jal on Mar 20 2007, 07:53 PM

The C2 research laboratory has acquired new equipment in the form of cheap web cam with its lens removed.
The active area of the CMOS cell zone looks to be about 2.5mm x 2.5mm.
The laboratory laser is an 'under 1mW' 650nm device.
The researcher is currently fueled by a relatively low octane South African red rated at 14.5% alcohol (known locally under the name 'Quadriplegia').

The following images were originally 640x480 pixels and have been reduced by a factor of 4.
The web cam is about 4 inches away from the pinhole .. not uncoincidentally the width of UK standard bog-roll.
The camera software includes automatic gain control.

Hole poked in black card

Black card away from the 'hole'


Hole poked in aluminium foil at centre

aluminium foil away from the centre


So how come the wavelength with the aluminium foil 'hole' looks to be about four times greater than with the black card hole?

I'm happy to go back and do it again but it would be nice if we had some 'reproducibility' here.

Comments welcome.
Best wishes,
-C2.

C2-

That's a pretty brilliant idea using a CMOS camera.

I have an idea. Insert a thin partially opaque screen, such as thin parchment
paper that is used for cooking, in front of the camera aperture. You will be
looking at the interference pattern with the camera from the backside of the
screen.

Other thin screen material ideas:

- 1 sheet separated from white 2 ply toilet paper.
- a piece cut from a white PVC plastic grocery shopping bag.

Try your dual slit experiment using such a thin material white screen. All you
should see is the interference pattern sans saturation of the CMOS sensor.
You will probably need to put the lens back onto the camera.

Oh yeah, at least 2 more glasses of wine.

LL

The hole poked in that aluminum is the same as a black card hole. Not bigger.

This post has been edited by Neil Farbstein on Mar 21 2007, 12:20 AM

Hi Confused2,

That is a very attractive set of pictures. The differences are probably due to differences in the regularity of the pinhole. An irregular margin would lead to secondary interference patterns. Your "source" could be considered composed of a large number of elementary smaller pinholes arranged in an irregular fashion. The more of these the finer the secondary interference pattern. Note that the hole in the aluminum is most likely the most regular one leading to the fewer "fringes". The other issue is you should use a spatial filter to reduce a lot of the "noise". It would all depend on if you can make a "perfect" hole. Usually they are made by a laser "punching" a fine one. The other way to do this is to smoke a glass slide with a kerosene burner and use a razor blade to score a line in the soot.

Another way to do this may be to start with a black mask with a perfect circle in it (computer generated in an image program) and go to a photocopier and keep reducing it and reducing it until it is really really small. The images being copied to transparency film such as used for OHP's.

Here is what you should get C2 with near "ideal" pinholes... starting with one on the left and pinhole sizes reducing toward the top and separation between pinholes increasing to the right.

It is not hard to imagine that your first image is an irregular cluster of very fine interference patterns summing due to very small apertures made from primary pinholes of a similar size to the ones on the top left whereas the overall size of the hole is like the one on the bottom left.

Cheers

This post has been edited by Good Elf on Mar 21 2007, 06:11 AM

Hi,

What about using an IR light source then using cameras to monitor the interior of the experiments interesting points/places...

Hi all,


Finishing my response to LL's post to me, now back a few pages. (and to his subsequent follow-up)

LL-

This is a little shaky. Each element (and isotope) has a specific mass, and a specific spectrum. This (the mass) can be given in frequency, but the spectrum is different. Each electron in the atom has a set of energy levels that can absorb/emit specific (resonant)"photons". These are the discreet frequencies that I am talking about (and are the basis for QM).

"#6" was the only thing left.

To restate this, I am basically asking if you have some Physical Law in mind, that says that these E~M waves can not "interfere" with each other. The reason that "seeing" the "white light" from the stars not being "distorted" is not good enough "evidence", is because A. "white light itself is an interaction, and B. practically ALL of the "photons" that we observe from stars have been absorbed & re-emitted countless times, before we "see" them. I have said before, that "constructive/destructive" interference is NOT enough to completely describe what is taking place between energy & matter.

Really though, I think its a mute point now.

We agree that there is no perfect vacuum.
We agree that a few gas molecules can act as absorbers/emitters.
We agree that matter is an integral part of the transaction.
We agree that the "absorption" takes place "outside" of the electron.

The fine point that we might still disagree on, is that, because I am saying that 2 electrons (in different atoms) are required for the "photon" to exist, then the interaction happens "in between" them. The energy (at these "visible" levels) never "penetrates" the electron. Superposition of energy waves takes place "outside" of the electron.

Not a very big difference, I think.

The other part, is the near field electric field (flux or density). To me, it doesn't matter whether this is the E field of the electron, or "photon": under the right, resonant conditions, there are interactions that can change frequencies.


C2,

Keep up the good work! Maybe you could start the first "bar-lab" combination. How did you get the photos onto the forum?


regards,

T.Roc

Thanks for the comments about the pictures. GE .. yes, lots of sources, I agree. I'll try smoked glass shortly, if it worked for the 'old guys' it should work for me. LL.. the reason for removing the lens was to eliminate one more operation and error possibility.. as it is I don't think the CMOS sensors can lie. The problem might turn out to be too much resolution over too small an area (about 2.5mm) but at the moment it seems perfect for checking the quality of slits and pinholes. I could disable the agc but this would be an extra complication.
Best wishes,-C2

Hi TRoc and All,

Agreed! You are correct, the spectral signature is a "set" of distinctive frequencies.

I think we must consider that in order for signal mixing to take place there
must be some medium to act as a non-linear integration source for the arriving
frequencies. An unstimulated atom vibrates at its own elemental frequency which
can be considered a local oscillator. When an atom becomes excited its electrons
become displaced from their normal orbitals and oscillating frequencies , especially
in the outer orbital. This electron displacement is a non-linear response to the
amplitude and frequency applied to it which causes the atom to "ring".
I still contend that frequencies don't mix spontaneously without some non-linear
physical displacement that functions as a point of mixing.

When signals are mixed they always have a different composite output frequency
that varies according to the frequency and the intensity of the signals being
mixed. Once mixed, the composite output signal is time and phase "locked".

Heterodyne detection: From Wikipedia

http://en.wikipedia.org/wiki/Heterodyne_detection

Heterodyning: http://en.wikipedia.org/wiki/Heterodyne

http://en.wikipedia.org/wiki/Heterodyne

Superposition takes place because of the non-linear displacement of the
detecting electron that is caused by the energy contained in the photon.
Energy, exists eternally...it just changes form depending upon the medium it is
interacting with. Once emitted, a photon exists infinitely until the energy it
contains causes a change of state in matter.


LL

This post has been edited by Laserlight on Mar 22 2007, 05:10 AM