conditions for evaporating water

[gib65]

I think this goes under classical mechanics (it's classical physics anyway).

 

Suppose I had a cooky try with 1/4 inch deep water in it. If I let it sit on the kitchen counter, would it eventually evaporate? If it would, how long would it take? If it wouldn't, what conditions, in addition to those listed below, would be needed?

 

My house is a little above room temperature (25 degrees celcius).

I live in Calgary, Alberta, Canada which is at an altitude of about 1 KM above sea level (and I live 5 stories up).

It's the spring season with temperatures around +20 celcius (on good days).

 

What if I left it out on the balcony on an average day (~20 celcius with mild winds)?

[RyanJ]

I think this goes under classical mechanics (it's classical physics anyway).

 

Suppose I had a cooky try with 1/4 inch deep water in it. If I let it sit on the kitchen counter' date=' would it eventually evaporate? If it would, how long would it take? If it wouldn't, what conditions, in addition to those listed below, would be needed?[/quote']

 

Shure it would - it may take a while but it would all evaporate eventually

 

The conditions are as long as there is enough heat some water molecules will gain enough energy to escape the surface cohesion, the higher the ambient temperature the more general energy and the faster the water molecules are given off. It also helps if there is a low moisture content in the local atmosphere and a breeze helps too as it effectivly moves the water molecules that have evaporated away.

 

Cheers,

 

Ryan Jones

[dirtyamerica]

Isn't this scenario technically called equilibrium? There is a lower amount of moisture in the air so the water goes into the atmosphere, one molecule at a time? Considering pressure and temperature, the water is not boiling to get into the air.

 

Please correct me if I'm wrong.

[insane_alien]

your not wrong but it can be assumed an open system since the atmosphere is hugely vaster than the volume of the water vapour.

[RyanJ]

Isn't this scenario technically called equilibrium? There is a lower amount of moisture in the air so the water goes into the atmosphere' date=' one molecule at a time? Considering pressure and temperature, the water is not boiling to get into the air.

 

Please correct me if I'm wrong.[/quote']

 

You are correct

 

The higher the water content of the atmosphere the more collisions the water in the air will have with the surface of the water and the more that will this "stick" too the waters surface via cohesion. At the same time there will be just as many evaporating so the water effectivley goes no-where... Whats why when you sweat in the tropics the sweat does not evaporate because the air is already saturated with water vapour

 

@insane_alien: Its normally more a case of the local environment rather then the atmosphere in a whole, for example a room is a vastly different system to the whole atmosphere is it not? So we should maybe treat this in the context it was asked

 

Cheers,

 

Ryan Jones

[YT2095]

assuming it`s a a straight walled container (and not in a bottle) and it`s pure water, then it`ll take roughly about 6 days to entirely vanish (still air).

that`s the Practical side of it anyway (from experience).

[RyanJ]

assuming it`s a a straight walled container (and not in a bottle) and it`s pure water' date=' then it`ll take roughly about 6 days to entirely vanish (still air).

that`s the Practical side of it anyway (from experience).[/quote']

 

How did you work that out? There must be some formula somewhere that can do it for you

 

Funny how things turn out, this happens to be a big part of my biology practical exam

 

Cheers,

 

Ryan Jones

[YT2095]

How did you work that out? There must be some formula somewhere that can do it for you

 

I didn`t work it out, and I don`t use Formula (if I can avoid it as I hate Maths).

this is pure and simple Practical experience

I`ve evaporated enough water to make Crystals in the past and water pure for the condensate to Know it`ll roughly take 6 days to do at 1/4 inch at 25c.

he can more or less expect a small and stuborn "puddle" in a corner that`ll seem to take AGES to go also

 

no formula, nothing complicated, just Reality gleaned over about 30+ years