One of the easily-forgotton tenets of science, or perhaps a commandment: Remember thy assumptions, for they may fail to hold.
Mpemba’s baffling discovery: can hot water freeze before cold? (1969)
[W]e see an admirable open-mindedness of Professor Osborne in his dealings with Mpemba, and that open-mindedness would quickly benefit them both. Conversely, we see a dangerous “groupthink” amongst Mpemba’s classmates regarding science, in which they are genuinely offended by Mpemba questioning the status quo. Mpemba shows great wisdom in his answer: “Theory differs from practical”. This is an important point for anyone studying physics: we like to create simplified models to explain nature, but those models often lose real-world aspects in the process of stripping them down.
One of the worst examples of flaming on a normally friendly science site concerned Mpemba. It came down to the argument that “your experiment doesn’t agree with my model therefore the experimental process is flawed”
I think it is humbling that we still cannot entirely understand the freezing of a container of water – at my last count there were at least six other simultaneous factors to account for other than the temperature. The usenet physics faq describes the importance and interest – “Mpemba’s story in particular provid[es] a dramatic parable against making snap judgements about what is impossible.