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

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.