Analysis:

The Schlieren experiment led us to the conclusion that Schlieren, at
least at regular video speeds, does not produce useful data about the
process of glass breaking under heat stress.  We were ultimately
unable to gather any useful data.  We did determine that glass doesn't
deform interestingly as it is heated; the glass doesn't change color
in the imager.

Future experiments with Schlieren could try using a high-speed video
camera.  If available, using a color high-speed video camera might
provide more information about the deformation, because of the
importance of hue in Schlieren imaging (hue indicates the direction in
which light is being bent).

Additionally, taking Schlieren video of a BB breaking glass could
provide useful data.  In our other experiments. we found that BB's
were more effective than heat expansion at providing both interesting
crack patterns and initial glass deformation.  BB's travel at a
high-enough speed that viewing them without a high-speed video system
or a synch-and-delay system with a still camera is unlikely to produce
useful data, so the NTSC video camera would need to be replaced.

