Why do thermos flask bottles advertise 24hrs cold and 12hrs hot. Shouldn’t it be the same amount of time for temps in both directions?
In: 1049
I hope I’m able to phrase this correctly, but it’s based on the 2nd law of thermodynamics: (paraphrased) heat always moves from hotter objects to colder objects. The thermos is acting as both insulator and conductor in this case. It’s conducting its heat to the outside world, albeit slowly, but it’s losing therms more quickly than it can absorb them from the “outside” ambient temps.
Cold does not conduct, or transfer, the way heat does – think of it this way: I can’t cool my house by opening the fridge, that just lets the heat in and warms my food. I can however warm my house by opening the oven, because it’s the heat that’s transferring.
In short, the thermos loses heat faster than it absorbs heat.
Latest Answers