4 - MIT OpenCourseWare http:/ocw.mit.edu 5.112 Principles...

Info iconThis preview shows pages 1–4. Sign up to view the full content.

View Full Document Right Arrow Icon
MIT OpenCourseWare http://ocw.mit.edu 5.112 Principles of Chemical Science, Fall 2005 Please use the following citation format: Sylvia Ceyer and Christopher Cummins, 5.112 Principles of Chemical Science, Fall 2005 (Massachusetts Institute of Technology: MIT OpenCourseWare). http://ocw.mit.edu (accessed MM DD, YYYY). License: Creative Commons Attribution-Noncommercial-Share Alike. Note: Please use the actual date you accessed this material in your citation. For more information about citing these materials or our Terms of Use, visit: http://ocw.mit.edu/terms
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
MIT OpenCourseWare http://ocw.mit.edu 5.112 Principles of Chemical Science, Fall 2005 Transcript – Lecture 4 Where were we last time? Last time we said we were setting aside the problem of the structure of the atom. We were setting it aside because we were stuck, and what we had to do was to look at another area of discussion. And that is this wave- particle duality of light and matter because it is that discussion that is going to give us the clues about how to proceed. We are putting aside the discussion of the structure of the atom all the way until next Wednesday, because next Monday I was reminded is a student holiday. [APPLAUSE] And so we started. We talked about the wave-like properties of light. We said that the property of superposition, the fact that you can put waves at the same point in space and their amplitude add. Since waves have both positive and negative amplitude that means that you have constructive and destructive interference. And it is those interference phenomena then that are evidence for wave-like property. And we did the two slit experiment to try to give you an example of interference phenomena. We were trying to understand those interference phenomena, and did so in terms of this diagram here. The interference phenomenon that we saw was an array, actually a row of bright spots, dark spots, bright spots, dark spots. And we drew these semi-circles here around each one of the slits. They represent a little bit of the wave that emanated through those slits. Because those slits are small then those wave emanated equally in all directions. That is why theses semi-circles represent the wave maxima. And what we discovered is that if we looked along this line here, this line which led to this bright spot, that all of the waves along this line were constructively interfering. That is we had the maximum of the two waves at the same point in space, or the minimum of the two waves at the same point in space.
Background image of page 2
And we noticed that everywhere along this line, where we had that constructive interference, the difference in the distance of the waves traveled was 1 lambda. We noticed here that everywhere along this line, that led to a very bright spot, we had constructive interference. And the difference in distance traveled by those two waves was 2 lambda. And, likewise, up here, along this line the difference in the distance traveled was zero lambda. And from just that, in a sense, qualitative observation we drew a
Background image of page 3

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Image of page 4
This is the end of the preview. Sign up to access the rest of the document.

This note was uploaded on 10/30/2008 for the course CHEM 5.112 taught by Professor Cummins during the Spring '08 term at Academy of Art University.

Page1 / 15

4 - MIT OpenCourseWare http:/ocw.mit.edu 5.112 Principles...

This preview shows document pages 1 - 4. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online