[bergerjac]

In 11th-grade 'Honors' Chemistry, we ran the 'Which water freezes faster' experiment outside in ~0℉.

2 glass beakers with same amount of water: 1 hot, 1 cold, stirring both at the same rate. Teacher told us the experiment was over once ice starting forming on the surface…

Cold water developed ice first. Outside in that weather, no one waited to see how long hot takes to become ice.

[dfdz]

In case you missed this in the article, the effect you described is a possible explanation of why the effect happens …

> Or perhaps external factors come into play: A layer of frost in a freezer can act as an insulator, keeping heat from leaking out of a cold cup, whereas a hot cup will melt the frost and cool faster.