It has always astonished me that physics textbooks are so poorly
written that they must be constantly revised. Surely there has
not been sufficiently rapid evolution in the concepts of physics
over the era of the seven previous editions to warrant new ones
on the basis of there being new material. The authors must be
correcting the many errors and misconceptions that appear in the
book. Since the *eighth* edition of a book entitled "Conceptual
Physics" is about to appear one must ask "Why the hell can't
they do a decent job of correcting the errors once for all time?"
I thought that an earlier edition of that book was indeed a poor
one, but surely seven times trying to improve it should be
enough!
Some of us mean spirited cynical types believe that new editions
of poor textbooks are published solely because the publishers
want to soak a new generation of students and they cannot do
that if used books are readily available. That makes the old
books (which are of no value to their owners - poor textbooks
never are) unsaleable by their owners. Inclusion of new problems,
or even the same problems in different numerical order, makes
it gratuitously difficult for a student to use an older edition.
Many professors don't care. The publishers give them their books
free, and few of my colleagues even ask what a book costs when
visited by a publisher's rep. I know, because I always ask, and
the reps are usually not equipped with that information!
I urge you to confront this situation as I do. I don't use the
textbook's problems at all; I assign problems separately. It is
more work than simply spewing out a string of numbers, but if I
do that then the students can use older editions of the text or
even other texts instead of buying a new one. I only have to do
this in first year courses, it seems. Good books (e.g. Reif's
"Thermal and Statistical Physics") do not appear in new editions
every two years. Students keep their books. When textbooks were
better at first year level that was also true; I still have my
copy of Sears and Zemansky. Another tactic you might try is to
seize on the appearance of a new edition of your first year text
as an opportunity to change publishers, and you should tell your
rep that is why you are doing it.
What I have said about introductory physics texts does not hold
for astronomy texts, the contents of which do change on a time
scale such that a five year old book is missing a lot of stuff
the student has heard about. Publishers (the same ones) should
be ashamed of themselves for this behaviour when selling physics
books, however. Perhaps there is some niche market out there of
ethical professors who do care what their students have to pay
for their books. Hello? Anyone else out there feel that way?