anyone know the double-slit experiment well?

link to short online paper describing the experiment (good article, clearly-written):

http://www.upscale.utoronto.ca/GeneralInterest/Harrison/DoubleSlit/DoubleSlit.html

i almost get it (& it is intriguing). but i still have a few questions right where the experiment has reached a certain stage: specifically, that's where a light bulb is introduced into the glass chamber in an attempt to track which slit the electrons pass through. after mentioning this change to the apparatus the author then adds the note, "we will see a small flash of light when an electron passes through the slits."

& this is where the paper seems too brief.

what's the need for a light source if the electron is already producing a flash? or does the presence of some light source somehow cause or permit one to see the flash? & then is it the location of this flash that indicates which slit the electron has passed through, or is that determination made in some other way?

thanks for reading & even more thanks if you can answer.

regards to all.

--z.

I suppose there is an interaction between the light and the electron which causes the "flash".

Originally posted by zaynsi
link to short online paper describing the experiment (good article, clearly-written):

http://www.upscale.utoronto.ca/GeneralInterest/Harrison/DoubleSlit/DoubleSlit.html

i almost get it (& it is intriguing). but i still have a few questions right where the experiment has reached a certain stage: specifically, that's where a light bulb is introduced into ...[text shortened]... way?

thanks for reading & even more thanks if you can answer.

regards to all.

--z.

Yes the light source is the author's way of detecting whether an electron is passing through the top or bottom slit. The "flash" refers to the observer spotting light presumably reflected from the electron passing through one of the slits. The electron does not produce the flash on its own.

It is this act of detection (light interacting with the electron) which destroys the diffraction pattern.

that makes sense. thank you.