A little tip i was given by my Dearly departed Nan, with regards to fast manufacture of ice cubes:
“Warm the water to lukewarm first ,then put in trays and freeze.”
‘Something to do with thermodynamics’.....”let’s all have a nice cup of Tea.”
The mother of my life-long friend (we met when we were five years old) always put the ice cube trays in the freezer with warm water in them. Didn’t know thermodynamics, but she was a clever ol’ farm girl and was very seldom wrong in her philosophies.
Well... not exactly.
It is true that the rate of change of temperature of the lukewarm water will be faster than the rate of change of temp for cooler/cold water (that part is thermodynamics) eventually the lukewarm water will reach the same temperature that the cold water would have been already. And THEN is has to cool some more to freeze...
But you used more energy to get the lukewarm water cold (that part is also thermodynamics...) in addition to the energy you used to get the lukewarm water lukewarm.. ;-)