Ummmm...
I recall (but couldn't likely reproduce any evidence or proof) that N3L doesn't work for moving charges (unless the magnetic field is included?).
I don't know of the conditions in which Snell's Law isn't accurate.
Any help / insight would be appreciated.
Thanks.
Paul Lulai
Physics Teacher
St Anthony Village S.H.
3303 33rd Ave NE
St Anthony Village, MN 55418
-----Original Message-----
Subject: Re: [Phys-l] Global Evolution as fact
Having co-taught a course in philosophy of science I can tell you that
the concept of a "fact" is not well defined in science because
scientific "facts" change over time. Some scientists (e.g. Aristotle)
once were absolutely sure the earth was at the center of the universe
(and they had perfectly good reasons to think so). A second problem is
we often teach "facts" that aren't really true (e.g. Newton's laws,
Snell's law, etc.). Just about any set of definitions that attempt to
distinguish between fact, law and theory either can be shown to be
inconsistent or flies against common usage (Kepler's laws are not true
but the theory of relativity is).