Thursday, April 18, 2024

Double Slit Ahead of Single Slit?

This is similar to my earlier query regarding the sequence of topics that are introduced. My earlier post was the order of introducing the concept of energy and the concept of momentum. In this post, it is the issue of the sequence of introducing the double slit interference ahead of the single-slit diffraction.

This sequence is done in Knight's text "Physics for Scientists and Engineers". I don't follow that sequence because I prefer to introduce the single-slit diffraction first, show the diffraction pattern, and then introduce the double slit. The fact that the double slit pattern has interference pattern inside a single-slit diffraction envelope is easier to explain after the students already know about the single-slit diffraction.

What do you think? How did you teach this topic, or how did you learn this topic?


1 comment:

Douglas Natelson said...

I think I learned double-slit first, in a simplified form - each slit acting as a point source of spherical waves in a Huygens-style approach, so that you can look at the phase difference between the two at the screen and get the overall interference pattern. Then, you build up single slit diffraction as a sum —> integral of such sources over the single slit width.