Re: Quantum Lab Experiment Question

[Wolfgang Rueckner <rueckner@FAS.HARVARD.EDU>]

Putting crossed polarizers in front of the slits is relatively easy
(I've done it plenty of times).  Cut the polarizer material at a 45š
angle with respect to the polarization axis.  Butt two such pieces
together with tape so that the polarizing axes of the two pieces end
up 90š w.r.t. each other, but 45š to the vertical (the slits, I
presume, are vertical too).  Put this dual polarizing mask over the
double slit and tape into place.  (If you use slits with a separation
of 0.5 mm, or even 0.25 mm, this is not too difficult to do.)  Having
done this, you will not get Young's double-slit interference pattern
-- just two superimposed single-slit patterns.  Now put a vertically
oriented polarizer downstream from the slits (between slits and
screen) and you will secure Young's double-slit pattern once more.

Wolfgang


> Hi
> I need some help. I am trying to prepare a quantum unit for a high school
> level physics class. The unit will only be a week long and is intended to
> serve as an overview of quantum.
>
> Here is my question:
>
> Would it be possible to ACTUALLY demonstrate (with HS equipment) that the
> interference pattern produced by the double slit experiment is destroyed by
> making an observation between the slits and the screen?
>
> Plenty of gedanken experiments in books and on web, but I really want
> something real. Plenty of simulations on the web, but nothing real.
>
> The most I can find is some talk of polarizers placed after the slits. Would
> I be able to do this with cheap polaroid sun glass material? Would try
> today, but it means getting to the school during summer break and opening
> the lab. Would be willing try if someone has constructive advice.
>
> TIA
>
> Scott
>
> --
> *****************************
> Scott Goelzer
> Physics Teacher
> Coe - Brown Northwood Academy
> Northwood NH 03261
> 603-942-5531 ext43
> sgoelzer@coebrownacademy.com
> *****************************