Re: Young's Interference, on the cheap

What did you use for the beam splitter? Young used two slits, and the
article that you cited employed a card. You did use something to split
the beam, right, since a pinhole will not do that.

The pinhole alone will give you a diffraction pattern, not an
interferrence pattern as in Young's Experiment. While both
interferrence and diffraction are both consequences of the wave nature
of light, they are quite different effects. Please take time to learn
the difference, else an error of this type can cost you dearly on an
advanced college placement exam.

For a simple sanity check, when you replicate the two beam experiment,
make some simple measurements and compute the observed wavelength. Then
compare your result with that published for your laser pointer.
Physicists and engineers refer to this as a sanity check, without which
you don't know what you are observing or its experimental validity.

Realize that I am trying to be helpful, not critical.

Good luck and kindest regards, Harry C.


Front Office wrote:
I think I might have succeeded, on the cheap, in doing
Thomas Young's demonstration of the wave nature of
light. Photos are at:

http://www.flashevap.com/Young.jpg

I used a Radio Shack laser pointer and a piece of brass
shim stock with a pinhole in it and a 0.005-inch diameter
wire in front of the pinhole.

I projected the pinhole light about two meters across
my office and onto the wall, where I took photos of
what might be interference of the red light.

The version of the experiment I am copying is shown
at the site of the Cavendish Laboratory:

http://www.cavendishscience.org/phys/tyoung/tyoung.htm

.

Relevant Pages

  • Re: Youngs Interference, on the cheap
    ... means that every ray would have exactly the same direction of travel. ... difference between interferrence and diffraction. ... wire in front of the pinhole. ... the beam, right, since a pinhole will not do that. ...
    (sci.physics)
  • Re: laser through pinhole
    ... I got a pinhole of 5 microns and need at least 1 mW ... Use a convex lens to focus down the beam. ... the hole with a commercial laser pointer. ...
    (sci.optics)
  • Re: Youngs Interference, on the cheap
    ... | Young's Experiment rather than some simplist web crap. ... | or the difference between diffraction pattern and interferrence ... |> | the beam, right, since a pinhole will not do that. ...
    (sci.physics)
  • Re: laser through pinhole
    ... I got a pinhole of 5 microns and need at least 1 mW ... Use a convex lens to focus down the beam. ... the hole with a commercial laser pointer. ...
    (sci.optics)
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