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Cake day: July 26th, 2023

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  • Eheran@lemmy.worldtomemes@lemmy.worldVapor dispersal.
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    2 days ago

    It has next to nothing to do with pressure, let alone temperature drop due to expansion. There are 2 things:

    1. When each one quantity of cold and warm air mix, the temperature of the mixture is almost exactly the midpoint (average), as the heat capacity is almost a constant.
    2. Vapor pressure of the water is a function of temperature and scales FAR more than linear.

    So now when the hot, humid (burned hydrocarbon) air of the exhaust mixes with cold air the temperature drops a bit, but the vapor pressure drops massively. When conditions are right, the vapor pressure is now below the amount of vapor pressure that is actually present -> condensation.

    vapor pressure over temperature data, note how it changes more than 2 orders of magnitude over only 100 K.

    Just found this from NASA.











  • Happy child free, may I ask how old you are roughly? Because to me it seems that this number and that happiness correlate strongly inversely. People are more and more lonely. Less family, fewer siblings, no children, …

    There sure are people of any age that are happy without children (or generally with or without anything). But since you mention this and me seeing that correlation: I have to ask. If you are 30 that is essential meaningless, like saying you do not care about pensions. If you are 60 both statements carry a lot more weight.