[dba-Tech] Single slit interference

[John W. Colby]

I am not a physicist so much of this is lost on me but I found the whole 
concept of "each point of a wave being a source for an identical wave" 
fascinating.  The guy does a remarkable job of explaining this 
graphically, along with the "how and why" of interference.

One thing I wish he had covered is what happens with full spectrum 
light.  He discusses it in terms of single wavelength (color) light, and 
how you get specific points of sum (bright) and the rest interference 
(dark).  I think that this is why we see a spectrum with full spectrum 
light, each color sums only at a single point(s) on "the wall" but of 
course this implies that we would see a full spectrum, much fainter, on 
either side of the major point.

BTW this same guy does other videos, one of which is about polarization, 
what it is, and what "circular polizarization" is, and how they use that 
in 3D movie glasses.  More cool stuff.

That is one of the cool things about YouTube, when you find an 
interesting subject (or author) you can poke around for similar stuff.

At any rate, in the photo-spectrometer I built

http://publiclaboratory.org/wiki/desktop-spectrometry-kit-3-0

They use a single slit on the end you see in this photograph, to "pre 
filter" the light before sending it through a diffraction grating.  It 
seems that the slit is used to crudely polarize the light, i.e. only 
accept light waves rippling in a specific direction.  Horizontal to the 
box if I visualize it correctly. Though I could be wrong about that.

One thing I am certain of, there are far smarter minds than mine and 
that is a good thing generally.

John W. Colby

On 3/27/2015 1:59 AM, Jim Lawrence wrote:
> Hi John:
>
> Definitely interesting...this link will be dropped on the desktop for further viewing.
>
> Jim
>
> ----- Original Message -----
> From: "John W. Colby" <jwcolby at gmail.com>
> To: "DBA Tech" <dba-tech at databaseadvisors.com>
> Sent: Monday, March 23, 2015 10:26:39 PM
> Subject: [dba-Tech] Single slit interference
>
> Cool stuff.
>
> https://www.youtube.com/watch?v=7CmbItRjM-Y
>