Titel rot
 

 

 

 

 

Substance-like quantities in the Karlsruher Physics Course (KPC)

In the KPC the substance-like quantities are the basic quantities. A substance-like or extensive quantity is a quantity, whose value refers to a region of space:

mass
energy
momentum
electric charge
entropy
amount of substance

To each of these quantities a density can be defined, and to each of them corresponds a current with a current strength and a current density. To each of them a simple and direct intuitive representation can be formed: It is convenient to imagine them as a measure of the amount of a substance, i.e. to apply the substance model.

The use of the substance model in the KPC has two consequences:
In mechanics momentum and momentum currents are treated right from the beginning.
In thermodynamics entropy and entropy currents are treated right from the beginning.

LiteraturE:
G. Falk: Was an der Physik geht jeden an?, Phys. Blätter 33 (1977), S. 616-626
F. Herrmann: The Karlsruhe Physics Course, Eur. J. Phys. 21(2000), S. 49-58