# Water evaporated

Hello everybody,

I'd like to ask a question.

I have one recipient with water, a little water in a box with not very much height as I show in the draw. We have atmospheric pressure and the temperature of the water is the same as the ambient temperature, about 20ºC.

My question is how much time does the water need to get evaporated.

Thanks

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## Answers and Replies

Shooting Star
Homework Helper
That will depend on the relative humidity and the rate of flow of fresh air over the water.

I would also like to point out, as an aside, that the temperatue of exposed water always becomes lower than the ambient temp within a short time due to evaporation, unless, of course, the air is saturated with water.

Pan evaporation is used to estimate such things as solar energy per sq measure and lake evaporation.

In the solar energy test two pans are used and one is open to the sun while the other is exposed to all the same conditions except that it is under a screen to shield it from the sun. The differential evaporation rate is used to calculate soler energy falling on the pan.

In the lake evaporation test only one pan is used and the time it takes to evaporate it is used to calculate the evaporation rate of the lake.

Below is a useful link for you

http://www-das.uwyo.edu/~geerts/cwx/penpan.html

Shooting Star
Homework Helper
I thought the OP was doing a little home Physics...

I thought the OP was doing a little home Physics...

That may well be, but the link I provided will prove helpful anyway.

again

Good morning,

I was reading the link you gave me but it's for lakes and things like that.

The question I propose it's for one recipient in one room, closed, with a normal temperature, pressure, relative humidity and we can think there isn't a flow of air above it.

Do you know anything about this case?

Thanks

The pan evaporation science is the same for indoor as well as outdoor cases. you just ahve to find charts that work for the conditions you want. Just Google for "pan evaporation"