frame a question of given answer :
If you hold a lid or a plate above boiling water, the steam touches the lid.
Answers
Answer:
When a lid is placed on a pot of boiling water, we see drops of water on the inside of the lid. Why?
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Well, boiling water from a pot produce vapour at about 100°C, about since it depends from the pressure and the distance (temperature drop) above the water surface.
This vapour will make contact with the lid of the pot, the lid will be at a temperature well bellow the 100°C, because its upper surface is in contact with the surrounding air (let's say 30°C) but hotter than that, since heat is transferred from the pot to the lid through metal heat conduction and from the vapours reaching the lid; we may assume that the lid will reach a temperature of let's say 60°C.
Now, as vapours (100% humidity, 100°C) contact the lid at 60°C (dew temperature less than vapour temperature), will condense in drops.
If you had your boiling pot in an oven and, carefully open the lid (now at the same temperature as the oven) you will not find any water drops