4 ms·
My favorite poorly understood phenomenon in basic physics is the Mpemba effect, where hot water can freeze faster than cold water under certain circumstances. I
by TillE 4y ago
My favorite poorly understood phenomenon in basic physics is the Mpemba effect, where hot water can freeze faster than cold water under certain circumstances. It's just phase changes of water in a simple experiment you can do at home, and I think there's still no widely accepted explanation.
- thaumasiotes 4y agoYou might want to find a phenomenon that everyone can agree exists. Failing to explain something that doesn't happen isn't very mysterious. https://en.wikipedia.org/wiki/Mpemba_effect https://en.wikipedia.org/wiki/Mpemba_effect > the actual occurrence of the Mpemba effect is a matter of controversy > In 2016, Burridge and Linden defined the criterion as the time to reach 0 °C (32 °F; 273 K), carried out experiments, and reviewed published work to date. They noted that the large difference originally claimed had not been replicated, and that studies showing a small effect could be influenced by variations in the positioning of thermometers: "We conclude, somewhat sadly, that there is no evidence to support meaningful observations of the Mpemba effect." > In controlled experiments the effect can entirely be explained by undercooling [water may cool below the freezing point without actually solidifying] and the time of freezing was determined by what container was used.
- NavinF 4y agoThat's because nobody's replicated that effect in a real lab. People who claimed to observe effect didn't even bother to bypass the freezer thermostat and force the compressor to stay on, nor did they measure power consumption. It's just shoddy science.