| Homework #4: Hobson Conceptual Exercises Chapter 8 - 11, 12 and Chapter 9 - 2, 9. In addition, do the problem accessible via the button to the right. This assignment is due by 5 PM Monday February 6 in the Drop Box for your tutor. | |
| Pre-Class Quiz #4 and the answers are available via the button. | |
Today we covered the material listed in the syllabus through §8.4 - Electric Force.
We used the figure to the right to amplify on the notions of order and disorder. We say that the upper system is more ordered than the lower one: all the red balls are on the left and all the blue balls are on the right in the upper system. In the lower system, the balls are distributed more randomly. So, since entropy measures the disorder, the lower system has more entropy. If the red balls represent molecules with high thermal energy and the blue balls represent molecules with lower thermal energy, than in the upper system, the left side is hotter than the right side. The lower system has equal temperatures on both sides. |
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| We also showed a Flash animation, that you may access via the button; separate window. | |
This animation is by Vera Fleischer, and is used by permission. The original site is http://www.web.virginia.edu/Heidi/chapter3/flash/ch3_deeperlook.html. Vera hangs out at http://mediasparkles.com/.
You may wish to know that the Flash animation uses the beginning of a quotation by Einstein, which finishes with the fragment we showed at the beginning of Class 6. Here is the complete quotation:
"A theory is the more impressive the greater the simplicity of its premises, the more varied the kinds of things that it relates and the more extended the area of its applicability. Therefore classical thermodynamics has made a deep impression on me. It is the only physical theory of universal content which I am convinced, within the areas of the applicability of its basic concepts, will never be overthrown." -- Einstein (1949)
| We showed a Java applet that simulates the double slit experiment for a water ripple tank. You can access the applet by clicking on the blue button to the right. An almost empty html file and the Java applet will each appear in separate windows. | |
As used in class we changed the following settings for the applet:
You may, of course, experiment with other settings if you wish.
Source for this applet: http://www.falstad.com/ripple. This page also provides access to full instructions on using the applet, the source code, etc.
| We asked two questions in class, available via the button. Separate window. | |
For the "Invisible Man" question, we discussed how there really isn't a single correct answer. However I argued that science tends to point towards the idea that he can not see. Others pointed out, correctly, that in science fiction we are not necessarily bound by science.
| Here is today's Journal file in pdf format. Separate window. | |
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