Class 10, 2/10/04
 Class highlights:

* Chau unveiled her !0-C list:

C1:  
    G, the Newton constant of his universal gravity.
    * We did discuss how it comes about and what units it has. Students need to review and understand.

C2:
    c, the speed of light.

    [We did not, but will, discuss the following:
    * It is a constant in the Maxwell equations for electromagnetism.
    * Also the Maxwell equations have the same form for observers moving with constant velocity.
    * The above two are the theoretical source for the two basic principles of Einstein's special relativity, although Einstein's discovery of special relativity was more intuitive.]

C3:
    h, or h-bar = h/(2pi), the Planck constant.
    * Planck had E = h x (neu) = (h-bar) x (omega) as the energy of a photon of frequency (neu). or equivalently, angular momentum (omego) = (2pi) x (neu).

    * Planck distribution of black body radiation.
    * Planck scales.

C4:
    Two principles of  (special) relativity
        A. The speed of light, c, is the same for all observers moving with constant velocity with each other;
        B. Laws of nature are the same for all observers moving with constant velocity with each other.
    Consequences:
        * E = m c^2,  and relation of  m to the rest mass, M.
        * Time dilation (which is independent of direction of the motion of a moving clock).
        * Length contraction (only in the direction of the motion of an object).

The 10-C list will be continued and further substantiated as the courses progresses.

* We viewed NOVA video (edited by Chau) about Einstein and his special relativity.
[Before viewing NOVA, Chau showed the web sites for Nobel Laureates who contributed the development of the 10-C's. (See web links in this class web.) Unfortunately, several important work did not get the Nobel Prize. Notably, Eienstein's special and general relativity, and Yang-Mills theory and their realization of the importance of gauge symmetry.]

*  Glashow, Salam, and Weinberg received Nobel prize because of their unification the weak with the electromagnetism, i.e., the electroweak theory.

* Yang-Mills' gauge symmetry is an common feature in electroweak theory and the strong theory (called QCD). The so called standard model includes both theories for electroweak and for the strong, however, electroweak and strong are yet to be unified.



*****  Following info was posted before the class. *******


Comments and hints to HW SA5.2:
    After assigning the problem, I realized (and checked) that you can find the answers on the web, either under "Planck length" or "Planck scales". Therefore, I would like to tell you that it is alright that you find the answers on the web. Then, you need to list the web site where you have gotten your answers.
    By the way, you will also find that most commonly people use h-bar (h with a slash; also remember that Mr. Greene of TB2 calls it H-bar?), which is defined as h-bar = h/(2 pi). [Do you remember in what context you have seen the quantity 2 pi before (surely in any high-school math)? I will remind you during the coming class. If you remember it and send me an e-mail about it, to be received by me before noon time, Tuesday, 2/10/03, you can get bonus.] Therefore, you can use h-bar, rather than h.
    Further, in the hand-in HW5, those who can show why the quantity you get from the web or created by yourself indeed has the dimension of a length can get bonus.

Announcement:
    In view of the coming Quiz 2 next week and also being the mid of the quarter, I will meet with you at the beginning of each of your discussion sessions, where we can have more direct in person discussions. Please review the course and bring with you all you comments, especially your concerns and constructive suggestions. I would like very much to make the course not only truly useful to you (which I am sure of), but also genuinely enjoyable to you (which I am less sure of, and I hope that you will help me to achieve).

Preview of the class
* Starting S2, Space and Time; and discuss important points.
* Showing video about Einstein and his special relativity, edited by Chau from NOVA.
* Discuss more about E = mc^2.
* Discuss further about taking square root on the back of the envelope.
* Unveil the "10 C list", and compose the Planck mass, time, and length from the first three C's.
*  Hand out graded HW3 & 4, with solutions.


Please read the following before you fill out the sign-up sheet.

(We will follow this routine notation from now on. Please try to review the class web page and have the answers ready before class.)

Sign-up items, Class 10, 2/10/04 
(1) Pages read of the current reading assignment in TB1.  #
(2) Pages read of the current reading assignment in TB2.   #
(3) Initial.