thermal physics~ help?

Question

If water in a sealed, insulated container is stirred, is its temperature likely to increase slightly, or decrease slightly, or stay the same? Explain your answer.

Given your answer to the above statement, why does stirring a hot coffee cool it down?

Answer 1

1..The disturbance causes some of the evaporated (gaseous) liquid to be re-absorbed into the surface of the liquid and, at the same time release more vapour into the vapour-space.
The liquid and its vapour will remain in equilibrium and therefore, at the same temperature.

2..The cup, being open to the atmosphere, on stirring the drink, the liquid on the surface is constantly changing causing an increase in the evaporation rate.
Also, due to the motion of the liquid beneath the air, this, in effect, increases in the breeze blowing over the surface removing the released vapour molecules more quickly.
The liquid will cool more rapidly.

Answer 2

a) by stirring the water in the container would increase its kinetic energy therefore raising its temperature.
b) When we have an ope container, like a coffee cup, he colder liquid settles at the bottom of the container. By stirring you are allowing the cold liquid from thew bottom to come up and mix with hotter liquid at the top. Evaporation is also play in a significant role. The evaporation is proportional to the area and bt stirring the effective area increases.

In an enclosed container surrounding water vapor quickly reaches saturation and prevents evaporation effectively.

Answer 3

(I think this would go with both questions) It would decrease the temperatures of the liquids because over time, the liquid would evaporate (especially the hot coffee). The hot liquid has molecules that move really quickly because of more heat, and they soon 'escape' to the air through evaporation. The average kinetic energy of the molecules decreases as more of them evaporate, causing the liquid to cool down.