It presents Kirchhoff's voltage «law» as representing conservation of energy
It presents Kirchhoff's current «law» as representing continuity.
It explicitly says These rules do not contain any new physical principles, but instead are simply the application of principles we have already encountered.
All three of those assertions are quite wrong. The errors don't matter much in the context of chapter 31, which is restricted to DC circuits ... but presumably the student is expected to remember the principles that are learned in chapter 31 and apply them in other contexts. In fact, as discussed in item #6, for AC circuits:
Violations of Kirchhoff's voltage «law» are routine, even though we still have conservation of energy.
Violations of Kirchhoff's current «law» are routine, even though we still have conservation of charge (aka continuity of current).
These «laws» embody a great many non-trivial assumptions, very different from the principles already encountered.
The ramifications for this for chapter 32 are discussed in item #6.
Suggestions:
The most helpful thing to say is that people _like_ the Kirchhoff way of looking at things, and often invest a lot of effort to design and build circuits in such a way as to minimize the magnitude of departures from Kirchhoff's «laws». It must be emphasized that this is an engineering choice, not a law of physics.
In chapter 31, emphasize that Kirchhoff's laws are more-or-less OK in the DC limit, but cannot reliably be extrapolated to AC circuits.
It is OK to mention that the current «law» is _distantly_ related to conservation of charge (aka continuity of current) _provided_ we make numerous assumptions about ideal wires and other components.
It is OK to mention that the voltage «law» is related to Faraday's law for induced voltage. Kirchhoff gets the right answer in the DC limit and not otherwise. Faraday gets the right answer always.
Do not connect the voltage «law» to conservation of energy.
In section 31.7 on page 835
representing conservation of energycontinuity.These rules do not contain any new physical principles, but instead are simply the application of principles we have already encountered.All three of those assertions are quite wrong. The errors don't matter much in the context of chapter 31, which is restricted to DC circuits ... but presumably the student is expected to remember the principles that are learned in chapter 31 and apply them in other contexts. In fact, as discussed in item #6, for AC circuits:
The ramifications for this for chapter 32 are discussed in item #6.
Suggestions: