Analogies in the Karlsruhe Physics Course

The KPC takes advantage of several analogies:

1. The analogy between the substance-like quantities allows for a simple mental representation of many physicall processes. They appear as a flow.

  Energy E                 Momenum p                    Electric charge Q            Entropy S                   Amount of substance n

  Energy current P     Momentrum current F     Electric current I              Entropy current IS      Substance current In

2. The analogy between momentum, electric charge, entropy and amount of substance allows for the use of a model,  where the difference of the values of the intensive variable appears as the cause of the current of the extensive quantity.

    Momenum p                       Electric chargeQ             Entropy S                   Amount of substance n

    Momentrum current F        Electric current I              Entropy current IS      Substance current In

    Velocity v                           Elektric potential Φ          Temperature T           Chemical potential μ

3. The analogy between momentum and angular momentum allows for a simple description of rotational mechanics.

    Momenum p                     Angular momenum L           

    Momentrum current F      Angular momentrum current  M

    Velocity v                         Angular velocity ω

    Mass m                            Momentum of inertia J

4. The analogy between electric and magnetic field strength results in a simplified presentation of the phenomena of magnetostatics.

    Electric charge Q                 Magnetic charge Qm

    Electric field strength E       Magnetic field strength H

5. The analogy between energy and amount of data (information) points to similarities between devices and processes in modern energy and information technology. 

    Energy E                  Energy current  P

    Amount of data H    Data current IH