Science question (not for school)?

Question

If water becomes water vapor at 100 degrees C, and is liquid water at any lower temperature, than how does water vapor stay as water vapor when it's at room temperature, wouldn't it be constantly condensing? Does this make any sense?

Answer 1

A liquid can evaporate and remain in the vapor state at temperatures far below it's boiling point. As a liquid is warmed, the vapor pressure doesn't stay at 0, then suddenly become 1 atm (760mmHg), when the temperature reaches its boiling point; it is a gradual increase.

You can get condensation if the amount of vapor present exceeds that which the air can hold at a specific temperature. This often happens when it cools down at night the air holds less water and we get dew, fog or frost.

Answer 2

Actually you are being misguided and not being told the whole truth.

Many liquids exist in their liquid and vapor phase at any given temperature.

Here is a thorough explanation:

The boiling point of water is 100c.
Boiling temperature by definition is this:

the temperature at which the vapor pressure of a liquid is equal to atmospheric pressure (1 atm)

At any given temperature a liquid does exist as vapor. There is what is called an equilibrium process occuring that is temperature dependent. You can think of this as a see-saw where the higher the temperature the more the liquid becomes a vapor and the more noticeable it becomes.

At room temperature there is water vapor although really do not see it.

If you take a glass of ice cold water and let it sit you will notice water forming outside the glass correct?

Well that is none other than the water vapor condensing from the air.

Answer 3

Water vapor does indeed constantly condense at room temperature, but at the same time the same number of water molecules also evaporate into the air. It's like inside a stadium, every time someone sits down another person gets up. That way an equilibrium is maintained, and the amount of water vapor in the air stays constant (as long as the temperature doesn't change).

Most objects stay dry because equal amounts of water evaporates and condenses on them. But some things, like crackers, croutons, cookies or chips, tends to prevent condensed water from evaporating. They would keep absorbing moisture from the air. That's why those food items lose their crispiness and become stale if you leave them in open air for too long.

Answer 4

Hmm... Well, the only thing i can figure is while it is still over 100 degrees celcius, it will diffuse and make its way outside and become part of a cloud, and that which doesn't make it's way outside gets caught on the windows and glasses throughout the house.