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Nod
03-31-2005, 03:14 PM
At the risk of sounding as though im attempting to sound intelligent. i know that in the equation E=hv, h (Planck's constant) is 6.6x10 to the power of -34. what i dont understand is how he came up with that particular number as the constant....
so can anyone explain this to me?
eestlinc
03-31-2005, 03:16 PM
not sure off the top of my head, but he probably studied the relationship between energy and velocity, realized it was a direct relationship, and calculated the constant from the ratio of the two.
Caspian
03-31-2005, 03:17 PM
Hahaha, you want us to explain to you a man's life work? He wasn't just any man either, he was one of the greatest physicists to ever live.

Ask a physics professor with a lot of time on his hands.
Nod
03-31-2005, 03:20 PM
no i do not wish for an explanation of the mans life work, i was only wondering about the process of how one 'finds' a constant, and used Planck as an example.
eestlinc
03-31-2005, 03:23 PM
I think I gave a pretty decent explanation of how you "find" a constant.
udsuna
03-31-2005, 03:52 PM
He's right, to find a constant, you simply calculate the relationship between two things. We do it all the time, but the most valid example I can think of is money.

1$ is worth four quarters, so how many quarters is 10$? The constant is 1:4... it's a really simple thing. Now, if you didn't know how much the value of a quarter was, you'd experiment. In this example, by attempting to purchase something, and comparing how many quarters you need as opposed to how many dollars.

Now, admittedly, when your dealing with atomic and astronomical calculations, things get a LOT more complex, but once you finally have the numbers (no small achievement), it's really easy to switch it back and fourth, simply by applying the constant to the value.
boris no no
03-31-2005, 03:56 PM
Hahaha, you want us to explain to you a man's life work? He wasn't just any man either, he was one of the greatest physicists to ever live..
he was an alien! :p
physics was my worst subject. i could never understand it. still cannot!
i'll stick to my biology! :p
krissy
03-31-2005, 04:49 PM
im assuming its the only number that worked for all the light tests he did


In 1900 he introduced Planck's constant as a part of his accurate formulation of the distribution of the radiation emitted by a blackbody, which is a perfect absorber of radiant energy.

or something liek that. cuz you know how the energy curve goes up, but then comes down (catastrohpe!).
Craig
03-31-2005, 05:09 PM
This thread makes my eyes itch.
K-chan
03-31-2005, 05:41 PM
no i do not wish for an explanation of the mans life work, i was only wondering about the process of how one 'finds' a constant, and used Planck as an example.

He didn't find a constant. He picked a random number and stuck it into the equation. :D Seriously though, eestlin and udsuna gave a good explanation
Denmark
03-31-2005, 09:32 PM
Avogadro's Number > Planck's Constant

by about 57 magnitudes of ten.
Nod
03-31-2005, 09:36 PM
ok, i understand now why Planck used the constant that he did. incidently, Planck was indeed a great Physicist, although many would say he could have been greater had he not been so obsessed with trying to reconcile classical physics with quantum physics. now that ive said that, could you close this thread please?
Emerald Aeris
03-31-2005, 09:49 PM
"he could have been greater had he not been so obsessed with trying to reconcile classical physics with quantum physics."

Gah, but that's so important! It's pretty much THE most important thing to achieve in modern physics.
eestlinc
03-31-2005, 10:16 PM
i think eoff needs more intelligent discuss, not less.
Emerald Aeris
03-31-2005, 10:17 PM
dear god yes.
Kirkpatrick
04-01-2005, 03:51 AM
Avogadro's Number > Planck's Constant

by about 57 magnitudes of ten.

However, Planck's Constant > Avogadro's Number by an unmeasureable amount of coolness and/or usefullness :p.
-N-
04-01-2005, 07:58 AM
The only constant I'm pissed about is Boltzmann's constant, b = R/n. Seriously, WTF? What a bastard, he can just divide 2 constants and name the result after himself?
radyk05
04-01-2005, 11:12 PM
not sure off the top of my head, but he probably studied the relationship between energy and velocity, realized it was a direct relationship, and calculated the constant from the ratio of the two.

its not a V, its a "nu" (greek letter for N whose simbol is a curled v) and it represents the frecuency of the light wave.

http://www.colorado.edu/physics/2000/quantumzone/photoelectric2.html