In the late nineteenth century it seemed that physics was largely complete. But a nagging problem arose when the idea that temperature represents the average…
In the late nineteenth century it seemed that physics was largely complete. But a nagging problem arose when the idea that temperature represents the average…
G Meazza4 January, 2014 at 5:30 pm
5:31 math begins
7:17 math sheet fully displayed
(I’m doing this because I want to find the math directly next time I’m
watching this video. Not a problem if I do this with your other videos ?)
Doomzdayxx7 December, 2013 at 3:58 am
These videos are great, thankyou very much.
Game Replays29 November, 2013 at 2:12 am
This might sound stupid but what do I need to learn to understand the math
in this video? I currently only have basic math knowledge and I’m looking
to study the prerequisites of QM alongside with QM.
Peter Joseph8 June, 2013 at 11:03 am
Checkout these excellent Quantum Mechanics videos. Probably the best I’ve
seen.
Rodrigo Castilho18 March, 2013 at 2:11 pm
Got it… So the uv catastrophe predicts infinite energy because there are
an infinite number of different frequencies in which the electromagnetic
waves that leave the black body could vibrate… Right?
viascience16 March, 2013 at 9:35 pm
Let me be more precise. Classically the energy of a single mode (a “wave”)
does not depend on frequency, only on amplitude. For a given range of
frequencies the total energy of all modes in that range will increase with
frequency because there are more modes at higher frequencies.
viascience15 March, 2013 at 4:08 pm
This is because the number of modes increases with frequency. The energy of
each mode is the same but more modes at higher frequency means more total
energy at higher frequency.
Rodrigo Castilho15 March, 2013 at 1:39 pm
But isn’t the uv catastrophe the prediction by classical physics that the
energy irradiated would be infinite because of infinite frequency?
viascience15 March, 2013 at 5:06 am
In classical physics the energy of a wave depends on its amplitude and not
on its frequency.
Rodrigo Castilho13 March, 2013 at 7:57 pm
Ok… and what’s the explanation, in classical physics, for the energy of a
wave to be dependent only of its frequency?
viascience12 March, 2013 at 3:45 am
Thanks – I hope it’s a brainer and not a headache. 😉
viascience12 March, 2013 at 3:45 am
Mechanical objects are composed of a finite number of atoms/molecules. It
follows that there are a finite number of modes of oscillation. When
thermally excited, each molecule has energy on the order of kT. So the
total energy is finite. But there is no limit to the number of modes of an
electromagnetic field.
tysondockins11 March, 2013 at 5:26 am
I’m getting either a brainer or a headache. Either way, awesome.
Rodrigo Castilho8 March, 2013 at 1:17 pm
Humm, I think I’m starting to understand this… But if classical physics
fails to explain the light bulb, shouldn’t it fail to explain the vibrating
violin string as well? As far as I know, classical physics has no problem
in explaining why the intensity of sound from a vibrating string is less
than infinite… By the way, thank you for atention!
viascience8 March, 2013 at 4:32 am
Exactly, so in the classical theory the bulb could not have a non-zero
temperature. That’s where it fails. To get an object to some temperature,
where it would be emitting an infinite amount of energy, you’d have to
supply an infinite amount of energy.
Rodrigo Castilho7 March, 2013 at 5:06 pm
But the bulb couldn’t possibly emit more energy than what’s supplied to
it… So, even from a classical point of view, the amount of energy emitted
must be equal to the amount of energy supplied to the system, not?
(assuming that the system is in equilibrium).
viascience7 March, 2013 at 4:07 pm
It predicts that the higher the frequency, the more energy is emitted. At
infinite frequency, infinite energy would be emitted.
Rodrigo Castilho7 March, 2013 at 3:10 pm
I don’t understand where the classical theory fails to explain the amount
of energy irradiated from the light bulb : (
Mike Gale22 November, 2012 at 12:26 am
Temperature is defined as a measure of kinetic energy. The constant k is
empirical. It’s basically just a unit conversion factor. Temperature is a
macroscopic quantity. How it translates into microscopic particle
velocities depends on your model of the material.
Mike Gale21 November, 2012 at 4:23 am
Your definition of N as the number of boxes seems superfluous as it doesn’t
occur in the equation. It might be worth mentioning that it’s used to
normalize the PDF. That is, the sum of P(n) from n=0 to N must equate to
unity. The 1/M factor emerges as N approaches infinity. You could refer
viewers to a website like mathworld.worlfram.com for more details about
this. Still a brilliant composition. You are doing us all a great favor
with these videos.
Xyrosis7 September, 2012 at 6:00 pm
Where did Boltzmann get ⟨E⟩ = kT from exactly?
sp00x6 September, 2012 at 10:24 pm
Sounds good – I just finished reading Brian Greene’s “The Fabric of the
Cosmos” and he was all stuck up and never covered those types of exciting
topics 😉
viascience6 September, 2012 at 9:37 pm
We’ll cover “quantum healing” of atoms – when an atom that is troubled by
too much energy and is healed by radiating some away. 😉
SpiritualAtheist6 September, 2012 at 8:24 pm
If this series is anything like your series on GR it should be great. Btw
… FIRST.
sp00x6 September, 2012 at 8:24 pm
Will you be covering quantum healing in this series? *g*