Re: [Phys-l] local conservation (was: non-grady ...)

[Steve Highland <shighlan@uslink.net>]

> I still want to cling to the idea that electric charge is real, tangible
> 'stuff' that I can hold in my hand.  Energy seems different, especially when
> you can freely label any state as 'zero energy' and get the same description
> of a system's behavior.  How can energy be real 'stuff' if you can
> arbitrarily say how much you have to start with? [SH]

"By way of analogy: Altitude is as "real" as anything could be,
yet it has a gauge invariance much like energy does.  The choice
of gauge has no observable consequences.  This doesn't make it
any less "real"."  [John Denker}


I like the analogy between altitude and energy -- for me they both are
missing the feeling of being 'stuff' in the sense that charge is like water.
My point wasn't about how 'real' these things are but more along the lines
of how "substance-like" they are...

On 02/18/2008 01:11 AM, Leon de Oliveira suggested:

> > Energy - a conserved substance like quantity that can be transferred
> > from one body to another or transformed from one form to another.


I suppose my gut feeling that electric charge is like some kind of goo
that's permanently jammed into some elementary particles is laughably
quaint.  My desire to see things this way may also explain why I can't get a
grip on how one permanently jams angular momentum into an elementary
particle -- angular momentum is another thing that just doesn't feel
"substance-like" to me.


I am searching for an example of an energy transfer that goes counter to the
local conservation argument you've expressed.  If I can find one then I'll
be better able to defend my gut feeling.  This will take some thought.

Steve Highland
Duluth MN