I observed a strange phenomenon today. I brought my milk and it was steaming hot so i left it for a while so that it could cool down a bit. It was cooled enough and there was cream on the surface and i started to drink after removing the cream. When the glass was approx 1/8 full i found the milk was cold and the difference in temperature when i started to drink and now could clearly be felt. Then i swirled the milk (like we do with test tubes to mix chemicals) and found milk was hot again. Is this phenomenon usual or just happened with me? Few other observations: The base of glass at the time i discovered this phenomenon was cold unlike the body. The glass was made of steel.
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$\begingroup$ Did you use a microwave oven to heat the milk in the steel 'glass', or did you heat the milk by another method and then pour it into the glass? Also what was the steel glass resting on? (in case it's possible that the heat at the bottom was conducted away) $\endgroup$– John HunterDec 24, 2021 at 21:14
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$\begingroup$ I used a gas stove to heat the milk and the glass was resting on a stone slab. $\endgroup$– Rahul SharmaDec 25, 2021 at 2:59
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$\begingroup$ Ok, all the best, Merry Christmas. $\endgroup$– John HunterDec 25, 2021 at 19:57
1 Answer
As the vessel was steel it's possible that the heat was being conducted away through the base of the 'glass'. The base would be in contact with the table.
This would cause cold milk at the bottom, it would stay at the bottom, as it's denser than the hot milk. The top of the glass would be hotter than the bottom.
When you drank, you'd come to the cooler milk. When you swirled it, the milk would come into contact with the hot part of the glass, higher up, and get hot again.