Explain this shit

>>7761695

Not 100% sure, but the water around the cup will never get above 212F (boiling point of water). Maybe they are saying that the water in the cup can shed it's heat out the top of the cup faster than heat from the boiling water can enter through the non-zero resistance of the walls of the cup?

>>7761699
>212F (boiling point of water).
the boiling point of water is 100 degree celsius.

Not sure if thats true but as soon as water reaches the boiling point(depending on airpressure) at 100°C, it wont become hotter. it will stay at 100°C. The cup keeps the temperature of the water in it always slightly below 100°C.

>>7761701
>the boiling point of water is 100 degree celsius.
Yeah, choice of measuring system is more important than the second law of thermodynamics.
You clearly have your priorities in order.

this >>7761707
if water surpasses the boiling point it turns into steam and leaves the system

>>7761701
The two are equivalent.

>>7761695
What is that app?

>>7761707
You basically rephrased the question

>>7761695
The water will boil.

looking at the diagram, it seems like the cup is sealed shut. We also don't know what the cup is made out of.

Shit question / 10

>>7761707
/thread
>>7761743
No, he didn't. Let me try to explain it.
First, consider these three facts;
1) water boils when it reaches 100° C and then you add additional heat to it
2) while it's boiling it keeps the 100° C temperature
3) between two bodies at different temperatures in contact there is a heat transfer from the warmer body to the colder body
4) the heat transfer rate is proportional to the temperature difference (and other factors that are of no interest to us now)
Knowing this, the water in the cup will receive heat from the surrounding water and its temperature will become asymptotically close to 100° C while never reaching it. Even if we wait an infinite amount of time for the water in the cup to actually reach 100° C, it won't start boiling since at that point it would need other heat for the phase transition, but being in thermodynamic equilibrium with the surrounding water no heat exchange happens.

Of course, this is all in theory, in reality there would be interactions with steam bubbles and the surrounding air that could be well over 100° C in temperature.

>>7761707
>>7761711
This is why engineers shouldn't be allowed on this board

>>7761701
>>7761699

>Not using Kelvin
fucking plebs

Depends on the heat source - if enough steam at over 100 degrees was produced, water in the cup could boil.

>>7761769
100°C is arguably the best way to describe the boiling point of water in standard conditions since that's the way it was originally defined.

The water will transfer heat to the other watermolecules by convection (warm water moves to warm other water). In the cup, heat can only be transferred through conduction.

I suppose as long as the cup's material has a specific heat equal or lower than water, it will allow the necessary heat to transfer into the cup's water.

However, once the bottom of the watermolecules in the cup is heated up, it will also transfer heat to the rest of the cup through convection.

>>7761781
The four elements (excluding aether) are arguably the best way to describe the constituents of matter since that's the way it was originally defined.

>>7761695

The conduction from the element to the pan is greater than 100C, raising the water to at least 100C where excess energy is shed by phase change of liquid to gas state.

The conduction from the 100C water to the cup cannot raise the temperature of the water in the cup to above 100C because 2nd law thermodynamics.

Some energy is lost therefore the energy imparted is always less than 100C in the water in the cup.

eventually all the water in the pot will have evaporated so that the cup is in direct contact with the heat source

The cup is really a red herring. The point is that the water that actually boils is going to be directly at the heat source, ie the steam rises up from the bottom.

>>7761760
The water outside the cup will boil away retard. Then guess what happens. Fucking engineers.

File: 1348595016340.gif (515KB, 700x795px) Image search: [Google]

515KB, 700x795px

>>7761886

You'll never be invited to an engineers party

If the heat source for the boiling water is the surface of the Sun, then yes.

File: Untitled.jpg (57KB, 757x707px) Image search: [Google]

57KB, 757x707px

>>7761794
if this is not bait i hope you are still in high school

>>7761695
Of course it will boil, as long as Q_out is smaller than Q_in

>>7761695
what if the water is saturated in salt

>>7761695
Depends on how insulative the cup is and the real temperature of the hot plate, the temperature profile from the plate to the cup could have a cup water temperature below boiling if the heat transfer coefficient is low enough.

>>7761695
Water outside of cup: 373K
Bubbles outside of cup: 373K
Water inside of cup: 373K
0th law of thermodynamics states 0 heat shall flow in
No enthalpy of vaporization -> no boiling

Did you all fail Gen Chem or something?

>>7763399
Congratulations, you've just created the hydro-meme drive :^)