Re: Test tubes for salt water cap?

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: Ian Macky <ian.macky-at-oracle-dot-com> 

 > 1) The walls of a beer bottle are somewhat thicker than that of a test
 > tube; assuming similar glass, the voltage at which you could operate would
 > be lower.  (If the glasses had a similar dielectric constant, however, the
 > thinner glass would give a greater capacitance - am I right?)

there are many kinds of "glass", an infinite number of formulations.
test tubes will likely be made of borosilicate glass (boron oxide
added: Pyrex, Kimex, etc), to reduce coefficient of thermal expansion
--> won't shatter when heat shocked.  regular glass fractures with
too sudden a heat change.  has anyone ever had problems with glass
bottle caps breaking?  no shrapnel i hope?