>        "What freezes faster, hot water or cold water?"
>
>        and just as importantly...
>
>        "Why?"
>
>        I just got off the phone with the Zamboni guy at the local
>        rink, and he says they fill the Zamboni with hot water because
>        "it's supposed to freeze faster."
 
        Karl, cold water freezes quicker.  To illustrate, set two
glasses of water outside on a cold day (assuming it gets below freezing).
Let one glass be room-temperature tap water and let one glass be very
hot water.  Actually, don't use real glass because the hot glass may
shatter - use plastic cups.  Anyway, assuming each cup holds the same
amount of water and both cups are of the same material, the one with
the colder water to start will freeze first.
 
        By the way, the mechanical engineer in me (Wow! I actually
get to use this stuff...) says that hot water is put in the Zamboni to
better melt the top layer of ice.  That way, it's easier to get rid
of all the blemishes in the ice surface.  I would bet the Zamboni guy
just tossed out an answer.  Anyone in the "cyber-rink" out there
have an opinion?
 
Carl Ford
Naval Research Laboratory
Ultraviolet Measurements Group
 
GO TERRIERS!!!
GO GOPHERS!!!