Exploring the Connection Between Forum Folders and Classical Physics

[Phrak]

Why is this Folder called Classical Physics?

General relativity is classical physics.

 

[maverick_starstrider]

What would you call it? "Classical Kinematics, Thermodynamics and Electrodynamics" doesn't have the same ring to it.

 

[Phrak]

What would you call it? "Classical Kinematics, Thermodynamics and Electrodynamics" doesn't have the same ring to it.

I know. And it's irritating. Why is there no designator to identify pre-relativity, pre-quantum mechanics based physics?

 

[maverick_starstrider]

.. "The good old days"?

 

[Phrak]

 

[Vanadium 50]

Why is there no designator to identify pre-relativity, pre-quantum mechanics based physics?

There is. "Classical physics".

 

[Nabeshin]

It has a sub-title...

 

[maverick_starstrider]

There is. "Classical physics".

He is right. Technically "classical" physics is a term in juxtaposition of "quantum" physics. Which means that relativity is technically classical physics.

 

[Vanadium 50]

No, Maverick_starstrider, Classical is a term that is used in contrast with both quantum physics and relativistic physics.

 

[Phrak]

Classical gauge theory comes to mind as a description of physics that discludes quantum mechanics and includes relativity.

 

[maverick_starstrider]

No, Maverick_starstrider, Classical is a term that is used in contrast with both quantum physics and relativistic physics.

"To what "classical physics" refers is dependent on the context. When discussing special relativity, it refers to the Newtonian physics which preceded relativity, i.e. the branches of physics based on principles developed before the rise of relativity and quantum mechanics. When discussing general relativity, it refers to the result of modifying Newtonian physics to incorporate special relativity. When discussing quantum mechanics, it refers to non-quantum physics, often including even general relativity. In other words, it is the physics preceding the physics of interest in one's discussion."

All kinds of vague.

 

[jtbell]

We have a forum named "Special & General Relativity," a few rows down from the "Classical Physics" forum. That should make it clear that in the context of PF, "Classical Physics" does not include relativity.

I think we have a bigger problem with the "General Physics" forum. My understanding is that it was intended for "general" physics-related topics that don't fit in the other forums in the "Physics" section. However, in the US at least, "General Physics" is the common name for a two-semester introductory physics course that covers basically classical mechanics and electromagnetism, so in practice most of the threads in "General Physics" could just as well go into the "Classical Physics" forum.

 

[Redbelly98]

The distinction between "General" and "Classical" physics at PF has often confused me.

In grad school, our Classical Mechanics course included special relativity but not general relativity. But, as, jtbell says, there is a Relativity subforum clearly labeled, so I think that distinction at PF has always been pretty clear.