[DVBC] Physics question

[Doug Bower]

Bob,

Thermal heat characteristics is probably the most misunderstood physical
science.  People believe many "wives tales", such as using hot water in
ice cube trays freezes faster.  As far as your water bottle situation is
concerned, Bob used hot water and Bill used cold water.  Assuming both
water bottles were the same non-insulated type, the same size, and both
bicycles were traveling through cold air at the same speed the heat
transfer rate would be the same.  The only difference in temperature of
the water inside would be for the first few miles where Bob's hot water
bottles would be giving its heat up to the environment.  Once Bob's
bottles transferred their heat and became the same temperature as Bill's
the physical laws of freezing would be the same for both Bob's and
Bill's water bottles.  There is only one other factor that I didn't
mention yet.  The only other factor that needs to be considered is what
was inside the water?  Did Bob and Bill fill their water bottles from
the same well?  The only way you can change the temperature at which
pure water freezes is by adding chemicals.  For those of us that still
remember 9th grade Science class, if you add chemicals such as the
compound salt, you raise the temperature water freezes at.  So bill's
bottles must have had some trace chemicals such as Gatorade or Cytomax.
If this isn't the case I have one more idea...  If Bob and Bill filled
their clean uncontaminated bottles from the same source with the only
difference being Bob used hot water and Bill didn't the hot water tank
or the hot water system is removing compounds from the water that the
cold water system is allowing to pass.  A simple experiment could be
performed to test this theory.  Fill two clean shot glasses with water,
one using cold water and the other using hot water.  Both shot glasses
must be filled with the same volume of water.  Place a lid upon each
shot glass to prevent evaporation of any trapped chemicals and let them
both sit on the counter until they reach room temperature.  Place them
both next to each other in the freezer, check periodically to see if one
shot glass if freezing before the other.   

Let me know hot the experiment worked, Doug

    

-----Original Message-----
From: dvbc-list-bounces at list.dvbc.org
[mailto:dvbc-list-bounces at list.dvbc.org] On Behalf Of Bob LaDrew
Sent: Sunday, January 21, 2007 4:32 PM
To: dvbc-list at dvbc.org
Subject: [DVBC] Physics question

    For today's ride I warmed up my bottle so it would go longer without

freezing. Bill used cold water in his. Mine froze right up and Bill was
able 
to drink out of his the entire ride.
    What is the operative law of physics at work here?
    Dougie, you wanna field this one?
    --Bob LaDrew 


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