Re: Specific Heat of Polystyrene Cups

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From: SFPhysics@aol.com
Date: Mon Feb 28 2000 - 12:58:42 PST 

From: SFPhysics@aol.com
Message-ID: <6d.19c96ec.25ec3b82@aol.com>
Date: Mon, 28 Feb 2000 15:58:42 EST
Subject: Re: Specific Heat of Polystyrene Cups

Hi Jeff:

Neil is correct. A key item to keep in mind is that the amount of
polystyrene is *very* small. Consider the mass of the cup and remember that
it is polystyrene *foam* so the cup is mostly air! Even the insulating
properties of the cup are in your favor as only a thin surface layer in
contact with the contents actually changes temperature with any rapidity.
The specific heat for air where the volume is constrained resulting in a
pressure rise is 0.725 starting at STP; but, since little of the captive air
is affected, this value is off little help. Just compute as if the cup was
not there. ;-)

Al Sefl

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