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What Physics fact or theory fascinated you the most?


SweetScientist
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I'm still learning the ropes of Physics but I really enjoy it and I remember being fascinated by light moving at "C" no matter what reference frame you measure it in. I know this is pretty basic stuff but, what are your perhaps more complicated aspects you found the most interesting or unbelievable? The double slit experiment is another one for me, that stuff was alien to me when I first researched it a little.

 

Also, even though I don't post much at all here, it's fun to lurk and learn from you guys as I assume a lot of people do.

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Some of the counter-intuitive stuff is really fascinating to me. I remember scratching my head over "If a bullet is fired from a gun at the same time a bullet is dropped from a table at the same height, they both hit the ground at the same time".

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Some of the counter-intuitive stuff is really fascinating to me. I remember scratching my head over "If a bullet is fired from a gun at the same time a bullet is dropped from a table at the same height, they both hit the ground at the same time".

 

That is something that is strange about Physics, things that seem simple enough don't really make sense with the model we have created in our heads through experience. One example of a similar idea that got me is if a man was going to shoot a cat, aimed at the cat along a horizontal plane then fired, and the cat dropped off the tree to try and dodge the bullet, and did fall adequately enough outside the horizontal plane the bullet still hit it.

 

Once someone explains to you that the horizontal and vertical velocity are independent then it all begins to make sense though.

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I'm still learning the ropes of Physics but I really enjoy it and I remember being fascinated by light moving at "C" no matter what reference frame you measure it in. I know this is pretty basic stuff but, what are your perhaps more complicated aspects you found the most interesting or unbelievable? The double slit experiment is another one for me, that stuff was alien to me when I first researched it a little.

 

Also, even though I don't post much at all here, it's fun to lurk and learn from you guys as I assume a lot of people do.

I love relativity. It fascinates me so much that I have spent up to 10 years working on solving a problem. I posted the problem in my website. It's about a rotating magnet. See

http://home.comcast.net/~peter.m.brown/em/rotating_magnet.htm

 

I loved working on it. It seemed to be so tricky that people even today are screwing it up. It has to do with the N-machine. This nutcase named Bruce DePalma claimed to have created a free-energy machine. The physics was rooted in a rotating magnet. He didn't have a good grip on relativity, perhaps no grip at all as a matter of fact. It was related to the Homopolar generator - which is hard to find in physis texts. I know of only one text that toiuches on it and its an SR text by Shadowtz. The nonsense goes on.

 

I'm reminded of something I read in a college course I took called Philosophy of Science. One of the texts was Science & Unreason, by Radner and Radner. In the Preface it reads

Nonsense has some surprising twists. You'd be surprised what you can learn by looking at it.

And I've found that to be very true over the last two decades. This rotating magnet is one example that comes to mind.

 

The SR text I mentioned above is Special Relativity by Albert Shadowitz, Dover pub (1968). See page 126. The topic is called the Faraday disc or homopolor polar generator. If anybody wants I'd be more than happy to scan it into a PDF file and place it on my web page for all to read. There are references in the American Journal of Physics.

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That is something that is strange about Physics, things that seem simple enough don't really make sense with the model we have created in our heads through experience. One example of a similar idea that got me is if a man was going to shoot a cat, aimed at the cat along a horizontal plane then fired, and the cat dropped off the tree to try and dodge the bullet, and did fall adequately enough outside the horizontal plane the bullet still hit it.

 

Once someone explains to you that the horizontal and vertical velocity are independent then it all begins to make sense though.

 

This is what hooked me. My next-door neighbor (older by a few years) told me this when he took high-school physics, and we made up an experiment in his basement with a blowgun and a solenoid trigger for a metal target to drop, and confirmed it. Worked pretty consistently, as long as you shot the dart with enough oomph. I thought that was so cool.

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Action principles have always fascinated me. Least action, Fermat's principle, maximal proper time, etc.

The term/principle Least Action is inaccurate. The correct term should be the principle of stationary action. See - http://en.wikipedia.org/wiki/Principle_of_least_action

In physics, the principle of least action – or, more accurately, the principle of stationary action – is a variational principle that, ...

The integral in the variation doesn't need to be least, it merely requires the first variation of the action integral to be zero. There are no requirments on the second variation.

 

This can also be found in Classical Mechanics - Third Edition, byGoldstein, Poole and Safko, Addison Wesley (2002), page 35 Eq. (2.1). The itegral is I = integrl L dt and the following words after that integral are

...where L = T - V, has a stationary value for the actual path of motion.

I believe this is proven in The Variational Principles of Mechanics by Cornelius Lanczos, Dover Pub. An Excellant text I should add.

 

The more general statement about proper time is that it's extremal, i.e. either maximal or minimal. I learned that about 13 years ago when I was helping the author of Exploring Black Holes by Edwin F. Taylor and John Archibald Wheeler. We (Edwin and I) discussed the principle of stationary action many times since I had to know it since I was writing the Glossary to the text.

 

I always wondered why there was no restriction on the second variation. Now I know.:P

 

I recommend learning about this. It's actually fun to do so!

 

 

 

 

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When I first came across relativity, I took a few days off school to try and wrap my head around it, and figure out what was really happening, so I could carry on with my Newtonian life...

 

Failing that, I went back to school...

 

Later I found Quantum physics very puzzling, and therefore very interesting.

 

2nd law of thermodynamics I found more intuitive, but equally fascinating, and when quite young I was amazed how gyroscopes seemed to cheat gravity.

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The term/principle Least Action is inaccurate. The correct term should be the principle of stationary action. See - http://en.wikipedia....of_least_action

 

The integral in the variation doesn't need to be least, it merely requires the first variation of the action integral to be zero. There are no requirments on the second variation.

 

This can also be found in Classical Mechanics - Third Edition, byGoldstein, Poole and Safko, Addison Wesley (2002), page 35 Eq. (2.1). The itegral is I = integrl L dt and the following words after that integral are

 

I believe this is proven in The Variational Principles of Mechanics by Cornelius Lanczos, Dover Pub. An Excellant text I should add.

 

The more general statement about proper time is that it's extremal, i.e. either maximal or minimal. I learned that about 13 years ago when I was helping the author of Exploring Black Holes by Edwin F. Taylor and John Archibald Wheeler. We (Edwin and I) discussed the principle of stationary action many times since I had to know it since I was writing the Glossary to the text.

 

I always wondered why there was no restriction on the second variation. Now I know.:P

 

I recommend learning about this. It's actually fun to do so!

 

Well yes, "stationary" is technically the accurate word. "Least action" and "maximal proper time" are the usual names used, and are almost always accurate names.

 

That's pretty cool that you got to work with Taylor and Wheeler.

Edited by elfmotat
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I am amazed at the frequency (no pun intended) that the sine function and the sine wave seems to crop up in so many branches of physics and engineering.

Edited by Joatmon
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I was amazed by the astronomical events that are so luminous they outshine entire galaxies--easily outshine them. When I first learned of quasars, I knew astrophysics was what I wanted to study.

 

Also, I think it's pretty cool that all "heavy elements" were produced by the death of a star.

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the whole concept of electricity i guess, i used to be an electrician and i still dont even really know what it is....and that man was able to figure out how to burn things and figure out how to turn it into electricity...amazing imo

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I'm finding that cosmology interests me the most right now. I did graduate work in physics 30 years ago, but did not stay abrest of developments in physics reaearch, having been diverted into a "career" in computer programming. But it is still fascinating for me now to catch up on the progress and developments over the last 30 years in that branch of physics research.

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At the moment I am most fascinated by how the sum of random numbers/effects can be predictable. Admittedly, the extent to what this qualifies as physics is debatable (it definitely plays a huge role in physics, but by itself it may be argued to be math). In the past, I remember that I found the property of linearity quite amazing. Again, that is arguably not that much physical by itself. But it but pops up all the time in physics (with "superposition" probably being the most widely known instance).

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Well yes, "stationary" is technically the accurate word. "Least action" and "maximal proper time" are the usual names used, and are almost always accurate names.

To m Least etc. are not the words that should be used since one never knows when which of them applies unless one already knows and doesn't need to determine it.

That's pretty cool that you got to work with Taylor and Wheeler.

Yes. It was very very cool. My name is in it and it's online so you can verify it. See

http://www.eftaylor....ront_matter.pdf

 

Go to the page where the word Acknowledgements is printed. Then look in right column and read where it says

Peter M. Brown made many suggestions, found quotations, drafted the Glosssary of Terms, and helped to assemble the reading list, and had the initial idea for the front cover.

This book is now used to teach a course in GR and black holes at MIT. And all those people who take that course read my name! :P

 

 

It was published at the right time. In June of 2000 I was diagnosed with Acute Myloid Leukemia. Edwin came to see me in the first week and handed me a copy of the book in which it was autographed by both Taylor and Wheeler. Nothing could have made me better. That's the kind of person Edwin is. I was fortunate to have him in my life at that time.

 

Pete

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Sorry to hear about your condition PMB, its not often we get to interact with forum members on a personal level.

 

What about J A Wheeler, did you have the opportunity to get to know him ? He is, to me anyway, one of physics' icons of the last century.

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One of the coolest things I remember learning about was at a colloquium when I was visiting grad school. The speaker explained how you could place an excited state atom in a cavity, and depending on whether the decay emission was supported or not by the cavity mode structure, you could enhance or suppress the decay. That is, you could keep an atom in an excited state for an arbitrarily long amount of time by removing the channel for it to release a photon, or you could make it decay much faster than normal by making to couple strongly to that mode. I soon learned a lot of interesting things about cavity QED and even though there was no research program in that subfield where I went to school, it helped cement my choice of atomic physics as my area of study.

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<br />Sorry to hear about your condition PMB, its not often we get to interact with forum members on a personal level.<br /><br />What about J A Wheeler, did you have the opportunity to get to know him ?  He is, to me anyway, one of physics' icons of the last century.<br />
<br /><br /><br />Unfortunately, no. I never got to meet him. Edwin lives a mere 30 minutes away from me and MIT is just a 45 minute drive. But Wheeler live in NEw Jersey and had and have no access to that mind of travel. Now that he's passed away I'll never have that chance.
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I find the property of fields interesting, for instance you can have a magnetic or electromagnetic

 

field that directly effects mass in the surrounding area but that mass is completly physicaly

 

un-connected with the mass creating the field. What are fields in a physical sence?

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  • 6 months later...

What got me hooked was learning about Newtonian mechanics, and being able to calculate the exact trajectory and final positon of an object in motion.

It is pretty standard stuff, but i found it fascinating that you could work out exactly where something would land, if you shot it at a certain speed and angle.

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