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General Science / Re: Does pressure in a thermos flask affect the temperature of the water inside?
« on: 22/03/2021 09:48:56 »
Nice question. I'd say yes, a bit.
The headspace gas above the hot liquid will be under pressure because heat from the fluid and the walls of the flask will heat the gas. When you open the lid, you release the pressure and the gas expands. This will drop the temperature of the gas and hence also rob some energy from the liquid because the gas has surface contact with the interface. But the effect will be very small.
The headspace gas above the hot liquid will be under pressure because heat from the fluid and the walls of the flask will heat the gas. When you open the lid, you release the pressure and the gas expands. This will drop the temperature of the gas and hence also rob some energy from the liquid because the gas has surface contact with the interface. But the effect will be very small.