Controversy continues over whether hot water freezes faster than cold
The answer is BOTH.  And sometimes neither.<p>Because this is literally about the time-domain solution to heat conduction and fluid dynamics (convention) with different initial conditions and boundary conditions (shape of vessel, temperatures at boundaries, etc.).<p>For example if there isn&#x27;t uniformity of initial temperature, if there isn&#x27;t uniformed of the applied cold sink, if there isn&#x27;t uniformity of heat flux capacity due to conductivity of the interfacing boundary conditions, etc.   There&#x27;s even questions about the water purity or contaminants which definitely would change the answer.<p>These are not and often can not be controlled.  And in practice at home, you will never duplicate even what the answer is in a control lab experiment.<p>It is the norm to have a range solutions that entirely depend upon initial conditions and boundary conditions.   And there&#x27;s also uncertainty of even knowing the values of these conditions.<p>Expecting a simplistic yes&#x2F;no answer to many problems ESPECIALLY those involving heat transfer and fluid dynamics is like asking for a specific date for your date from your date of birth or your childhood medical history.<p>See also climate change - we DO NOT KNOW there is a specific date when things &quot;tip&quot; and ANYONE claiming there is a date let alone timeframe is a liar or so ignorant they can&#x27;t possibly be right!   The error of any model is larger than the estimate value itself.<p>You&#x27;d think people would have learned something from the 20th century about the FACT that we do not live in a 19th clock-work universe with complete predictability.  We know how it can never be predictable especially if fluid dynamics is involved - you know, mathematical chaos and all.