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Two questions.
1. As coffee in a cup cools down, will there be random spikes where the heat goes slightly up, even a tiny tiny tiny bit while the general trend is that it cools down.
2. If you had a tap of running water from a height, going down onto a heated stove or something, could the stove transfer heat up the running water so that if you put your finger through water near the top, you would feel it heat up (without evaporating it and without the heat transfering through the air or something)
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>>8500698
I'm gonna go ahead and say no and no. Gl with your hw
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>>8500698
First Question: No
Second Question: Dunno, why don't you go pour water on your stove
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>>8500698
assuming you're measuring with a thermometer probe, then yes the temp will vary. you are measuring a single point in a moving fluid, hot and cold spots create currents as it falls to a stable temperature.
no, conductive heat transfer propagates on the order of millimeters per second, even in metals. the falling water would be moving much faster than the heat could conduct to the top.
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>>8500698
>1. As coffee in a cup cools down, will there be random spikes where the heat goes slightly up, even a tiny tiny tiny bit while the general trend is that it cools down.
If you look macroscopically at the coffee no, the temperature will always be decreasing. If you look at individual molecules yes they will from time to time spike upwards but that is true in general of all substances.
>2. If you had a tap of running water from a height, going down onto a heated stove or something, could the stove transfer heat up the running water so that if you put your finger through water near the top, you would feel it heat up (without evaporating it and without the heat transfering through the air or something)
The thermal conductivity of water is no where close to high enough to make any meaningful increase in temperature at the tap. I can't be assed to try to calculate it but you're probably looking at less than 10^-12 watts or something ridiculous like that.
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2: heat transfer equation in one direction, speed of water in the other.
practically no, but depending on your setup possibly measurable (over very short distances in slow running water) if the water flows faster than the speed of sound (in water) the heat will no transfer upstream except through radiation
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>>8500698
1. no unless something randomly adds heat to it, so no
2. No, the water would not be able to heat up until it interacted with the heat given off from the stove. While a very slow moving liquid could probably have this happen, water falls too fast for the heat to get to the water further up the stream as by the time the water molecule above the one that just got heated receives heat from the one below it is already in the stove's area of heat
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