From: Ronald Wong (ronwong@inreach.com)
Date: Wed Dec 18 2002 - 02:03:50 PST
Message-Id: <l03102801ba25e80cc913@[209.209.19.158]> Date: Wed, 18 Dec 2002 02:03:50 -0800 From: Ronald Wong <ronwong@inreach.com> Subject: Re: grain elevator and questions
A few "common" examples to add to Paul's list:
Mike Schulist asked:
>2. "do other substances sublimate besides dry ice?"
Mothballs (naphthalene).
Just like a puddle of water on the sidewalk can evaporate and turn into a
gas even though it's below the boiling point, a solid can sublime into a
gas even though it's below the sublimation point (but at a far slower
rate).
Have you ever wondered what happened to the ice cubes in the ice-tray that
were sitting untouched in the freezer of your frost-free refrigerator for
ages? They sublimed into the air.
>3. "Is plasma a higher energy state than a gas? Where else does
plasma exist besides the outer atmoshpere and in fires?
Anytime you have an ionized gas, you have a plasma. So neon signs,
fluorescent tubes (where the plasma produces the UV that is then converted
into visible light by the fluorescent coating), bolts of lightning, the arc
produced during arc welding (or by students who short out an electrical
circuit), as well as those novelty items that consist of a sphere with
glowing streamers moving around in them which respond when you touch the
surface of the sphere with your hand/fingers (the Exploratorium has an
beautiful piece of artwork that works on the same principle) are additional
examples of where plasmas can be found.
ron
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