# Homework Help: If the air is 212 degrees F will water boil?

1. Apr 29, 2013

### willstaruss22

I've been trying to figure this our for a while now. My science teacher asked this question and he wants an answer by tomorrow but I have no idea. Can anyone help with this?

2. Apr 30, 2013

### SteamKing

Staff Emeritus
What must the temperature of the water be for boiling to occur? If you put a pot of water on a gas stove, the temperature of the flame is much hotter than 212 F. Does the water boil immediately?

3. Apr 30, 2013

### Staff: Mentor

In some places it will sometimes boil, in some it will never boil. Question leaves an important factor out, making the answer ambiguous.

4. Apr 30, 2013

### Joseph King

Also, keep in mind that boiling points for liquids change with altitude (though, I assume the question is for sea level).

5. Apr 30, 2013

### Staff: Mentor

With pressure to be precise. Which is exactly what I was referring to.

6. Apr 30, 2013

### willstaruss22

Yes I'm talking at sea level. Like if the air temperature was 212 degrees F would the oceans boil away?

7. Apr 30, 2013

### HallsofIvy

In order to boil, the water must have a temperature of 212 degrees farenheit. If the water sits in 212 degree air long enough, it will eventually reach that temperature.

8. Apr 30, 2013

### Karshtakavaar

The water will eventually reach a thermal equilibrium (where all elements in the system are at the same temperature). However, if my memory serves me, there are important elements of the question missing. Tt isn't specified whether or not the heating is constant. For example, if you heat only the air inside of an insulated container to 212 F, and fill it with cold water, the heat will impart kinetic energy into the water, thus heating it up, until the temperatures are equal. This is not at 212 F, because as the air tries to reach thermal equilibrium with the water, it loses temperature itself. Therefore, it would not, in a closed system with insufficient energy.

HOWEVER, if this is a system where the air is constantly heated, then YES, it will eventually reach thermal equilibrium. As an example, if the sun was hot enough to where the air at sea level was 212 F, the sun is constantly heating the air, so it doesn't matter how much kinetic energy it puts into the water. The water would eventually reach 212 F, from the air, and the oceans would boil away over time. (Note: This is a flawed example, because the ocean has salt in it, which alters the boiling point. Just assume that this is pure water, with no additives.)

So, essentially, if the air is losing kinetic energy as it heats the water, this will not heat it to boiling.

9. May 2, 2013

### Staff: Mentor

I think the answer relies on your definition of boiling. It isn't just asking will the water evaporate; it will do that below 212. I think it's asking will bubbles of vapour form within the liquid, i.e., beneath the surface.