- #36
the_emi_guy
- 766
- 79
clamtrox said:If you insist calling a particles energy it's mass, then sure :D I usually call mass mass and energy energy, so there's no confusion.
ZapperZ said:What "relativistic mass"? The "missing mass" is in the binding energy!
I definitely agree with clamtrox here. Mixing up those two, especially when someone isn't familiar with the concept, is causing nothing but confusion.
Zz.
Are you are saying that the rest mass of an atom should exclude the binding energy (since it is energy and not mass)? Should we also exclude the binding energy of the gluon field that holds its constituent quarks together? Or should we arbitrarily consider that gluon field to really be a gluon particle so that we can include its mass (which turns out to be the lion's share of the quark mass)?.
What is rest mass? As Naty1 pointed out, rest mass includes numerous energy components, both kinetic and potential. 1Kg of uranium consists of the rest mass of quarks, qluon field energy, atomic binding energy, thermal kinetic energy etc.
All of these mass-energy components make up its 1Kg rest mass.
Now it seems odd to me that if I now set this complex 1Kg package of mass-energy in motion, that I am obligated to record the increase in energy in Joules, not Kg, because it happens to be motion.
And, yet, if I place this moving 1Kg into a larger, stationary, container, its kinetic energy is now allowed to be converted to Kg and counts toward rest mass of the larger container.
I know that teaching relativistic mass has gone out of favor, and for some valid reasons, but I think that there is an unintended consequence.
Students should not get the impression that mass and energy are fundamentally different things or that e=mc^2 is a rule that tells how much of one can be converted to the other.
Energy can neither be created nor destroyed, and energy, in all of its forms, has mass.
Mass also can neither be created nor destroyed, and in all of its forms, has energy.
Mass and energy are two names for the same thing, and neither one is changed nor transformed into the other.
Rather than mass being changed into energy, the view of special relativity is that rest mass has been changed to a more mobile form of mass, but remains mass. In the transformation process, neither the amount of mass nor the amount of energy changes, since both are properties which are connected to each other via a simple constant.