From: Jmgoldberg <Jmgoldberg@aol.com>
Date: Tue, 6 Jan 1998 00:04:11 EST
To: pinhole@exploratorium.edu
Subject: wave reflection
There are two things about waves that have been driving me crazy. First, how
can I explain to my students that a wave travelling along a medium like a
spring that is loose on one end (or fixed to a "loose" medium) will reflect
with no inversion. They'll accept wave reflection so as to conserve energy,
but no inversion after they can visualize a Newton's third law description of
a reflected wave being inverted at a rigid barrier makes them very unhappy.
Got a good explanation?
Second, so (window) glass is opaque to UV, at least that's what I've thought.
My students insist they get sunburns through car windows and I tell them
they've got poison ivy. Is glass opaque to all UV frequencies? How thick
does it have to be?