Sean thats very interesting, its called the Mpemba effect but it relies on certain conditions to be present and the exact reason for its occurance is unknown, people can only speculate. I tested hot and cold water on glass and hot water dries 4x quicker than cold, Luke
ps. I suggest everybody reads this article about the mpemba effect.
http://physicsworld.com/cws/article/print/24493Although it is infact sometimes true certain circumstances, you will see from this article that it isnt always true that hot water freezes quicker. To have a definitive answer an experiment would need to be carried out that applies ONLY to a WFP WC circumstances. Different things will effect the mpemba effect:
the cold waters temperature
the hot waters temperature
the windows temperature
Unless the experiment is carried out on many houses ( different internal temperatures affecting glass temperature ) then the test will not be fair as the mpemba effect is by no means reliable. It is unlikely that hot water in excess of 90c would freeze quicker than water that is 5-10c but if the hot water is at 60-80c when it hits the glass there is a chance it would freeze qucker on a freezing day. Luke