Sri Venkateshwara College, Delhi Univ.

Farewell - Physics Hons. Class 2008

2008-03-17T12:18:00.004+05:30

GoD! dis is da special Chak-De-Venky moment!! got a litt'l blur'd..bt da moment stays!! :)

Venky!! @ Google Earth, ;)

2007-12-22T02:27:00.000+05:30

22nd Dec, Winter Solstice Day @ Jantar Mantar, New Delhi

2007-12-21T01:23:00.000+05:30

Participate in the Historic Calibration Work of the Jantar Mantar Observatory Instruments!

Be at the Jantar Mantar on the 22nd December, the Winter Solstice Day to participate in the historic calibration work underway for the Jantar Mantar Observatory instruments.

Have you been wondering what exactly are those structure-instruments? How do they tell the time? What other things can they be used for? Et cetera. Then I guess, that's the right platform to interact and know, do and learn, talk-discuss about your doubts, etc.

Further, you can also look through the telescopes there in the evening for certain celestial objects too!

Volunteers from the Nehru Planetarium & the Amateur Astronomers Association, New Delhi will be present at the observatory between 11 am to 5 pm (and maybe little beyond) on the 22nd Dec. They would assist and help-out students and visitors understand the astronomical significance and usage of these instruments. Once again, you should feel free to ask any questions you may have!

From Sunrise to Sunset, the position of the Sun, in the bowl of the Jaiprakas instrument will be traced by volunteer observers (you can be one of them too!!). Why? This will trace out the Tropic of Capricorn in the bowl, one of the markings originally present on the instrument.

Also, at 4 pm starting at the Misra Yantra, there will be a lecture on all the observatory instruments which will be conducted by Dr. Rathnasree, Director, Nehru Planetarium.

Its an opportunity to learn and know, a platform to know something new, etc. and off-course be a part of the historic calibration process.

FOR EVERY ACTION, THERE IS AN EQUAL AND OPPOSITE REACTION? "NEWTON"......said otherwise

2007-11-04T17:30:00.000+05:30

CORRECTED: For every action, there is not an equal and opposite reaction.(William J. Beaty)

Newton originally published his laws of motion in Latin, and in the English translation, the word "action" was used in a different way than it's usually used today. It was not used to suggest motion. Instead it was used to mean "an acting upon." It was used in much the same way that the word "force" is used today. What Newton's third law of motion means is this:
For every "acting upon", there must be an equal "acting upon" in the opposite direction.
Or in modern terms...
For every FORCE applied, there must be an equal FORCE in the opposite direction.
So while it's true that a skateboard does fly backwards when the rider steps off it, these motions of "action" and "reaction" are not what Newton was investigating. Newton was actually referring to the fact that when you push on something, it pushes back upon you equally, even if it does not move. When a bowling ball pushes down on the Earth, the Earth pushes up on the bowling ball by the same amount. That is a good illustration of Newton's third Law. Newton's Third Law can be rewritten to say:
For every force there is an equal and opposite force.

Or "you cannot touch without being touched."

Or even simpler: Forces always exist in pairs.

INFRARED LIGHT : A FORM OF HEAT ?

2007-11-04T17:19:00.000+05:30

CORRECTED: NO, INFRARED LIGHT IS NOT A KIND OF HEAT (William J. Beaty)

Infrared light is invisible light. When any type of light is absorbed by an object, that object will be heated. The infrared light from an electric heater feels hot because the light is EXTREMELY BRIGHT LIGHT. Just because human eyes cannot see the light which causes the heating does not mean that the light is made of some mysterious entity called "heat radiation." When bright light shines on an absorptive surface, that surface heats up.

And this is no benign misconception. Those who fall under its sway may also come to believe that *visible* light cannot heat surfaces (after all, visible light is not "heat radiation.") Misguided science students may wrongly believe that warm objects emit no microwaves (since only IR light is "heat radiation"), even though hot objects actually do emit microwaves. Or they may believe that the glow of red hot objects is somehow different than the infrared glow of cooler objects. Or they may believe that IR light is a form of "heat," and is therefore fundamentally different than any other type of electromagnetic radiation.

In his book "Clouds in a Glass of Beer," Physicist C. Bohren points out that this "heat" misconception may have been started long ago, when early physicists believed in the existence of three separate types of radiation: heat radiation, light, and actinic radiation. Eventually they discovered that all three were actually the same stuff: light. "Heat radiation" and "actinic radiation" are simply invisible light of various frequencies. Today we say "UV light" rather than "actinic radiation." Yet the obsolete term "heat radiation" still lingers. Since human beings can only see certain frequencies of light, it's easy to see how this sort of confusion got started. Invisible light seems bizarre and mysterious when compared to visible light. But "invisibility" is caused by the human eye, and is not a property carried by the light. If humans could see all the light in the infrared spectrum, we would say things like this: "of COURSE the electric heater makes things hot at a distance, it is intensely BRIGHT, and bright light can heat up any surface which absorbs it."

PS, if you're interested in physical science misconceptions, Bohren's Book is an excellent resource. He's like me, and complains about several specific misconceptions which keep his students from understanding science.

Academic Calendar 2007-08

2007-10-21T22:27:00.000+05:30

Caution!!

2007-08-18T21:17:00.000+05:30

Blogging Know-How

2007-08-17T22:43:00.000+05:30

Release Date: July 06, 2006

An introductory insight into blogging.

Posting on the blog:
Step01. Open website: www.blogger.com, enter username and password. Click --> Sign In. (click on the image below)

Step02) Post login, is the 'Dashboard' page, which lists all the blogs one is a member of, date of last update, and the number of posts on the respective blog. We strongly encourage you to update your profile towards the top-right of this page. (click on the image below)

a) In case you are the administrator, click on the icon to view/change settings.
b) Click on the icon to write a new post.
Enter the following details,
i) title of post,
ii) text and picture content; options to edit (bold, italics, alignment, picture, hyperlink etc),
iii) preview (optional),
iv) save as draft (optional), and
v) publish post (the post will now be viewable on the blog)
(click on the image below)

Comments:
Step01. Open the blog webpage and Click --> Comments

Step02. Post-clicking, follow the options to write your comments and post the same. (click on the image below to view the options - squared and circled in red)

Further reading:
1. Help @ Blogger
2. Buzz @ Blogger
3. Weblogs @ Wikipedia

I would appreciate if the reader of this post would post comments/suggestions for improvement etc.