RE: ciepła woda zamarza szybciej niż zimna

At 12:08 2006-04-04 +0200, you wrote:

>Subject: ciepła woda zamarza szybciej niż zimna
>
>Ot, taka ciekawostka:
>http://physicsweb.org/articles/world/19/4/4/1
>
>
>
>>Znowu Prima Aprilis ?

Nie, to od dawna znane zjawisko. Nawet przebadane:

Knight CA
<http://www04.sub.su.se:2075/?SID=A5jipHpKODKelkGIlI4&Func=Abstract&doc=2/1>The
Mpemba
effect<http://www04.sub.su.se:2075/?SID=A5jipHpKODKelkGIlI4&Func=Abstract&doc=2/1>:
The freezing times of hot and cold water
AMERICAN JOURNAL OF PHYSICS 64 (5): 524-524 MAY 1996

AUERBACH D
<http://www04.sub.su.se:2075/?SID=A5jipHpKODKelkGIlI4&Func=Abstract&doc=2/2>SUPERCOOLING
AND THE MPEMBA
EFFECT<http://www04.sub.su.se:2075/?SID=A5jipHpKODKelkGIlI4&Func=Abstract&doc=2/2>
- WHEN HOT-WATER FREEZES QUICKER THAN COLD
AMERICAN JOURNAL OF PHYSICS 63 (10): 882-885 OCT 1995
Abstract: Temperature measurements taken near vessel walls show that
initially hot water may well begin to freeze quicker than cold. This is
not, as previously surmised, due to the cooling history of the water (e.g.,
air expulsion during heating). Rather, supercooling virtually always takes
place. On those occasions where the cold water supercools sufficiently more
than the hot the Mpemba scenario is the following: The hot water
supercools, but only slightly, before spontaneously freezing. Superficially
it looks completely frozen. The cold water (in larger volume than that of
the hot sample) supercools to a lower local temperature than the-hot before
it spontaneously freezes. This scenario can occur more often for ambient
cooling temperatures between -6 degrees C and -12 degrees C.

Michał

-- 
Michał Sobkowski, IChB PAN, Poznań
http://www.man.poznan.pl/~msob/
"Każdy złożony problem ma proste, błędne rozwiązanie!"
[U. Eco]