Why is it faster to boil water with the lid on

[terryphi]

I always though water boiled faster with the heat on simply because the lid retained heat.

However, I was thinking about the enthalpy of vaporization.

Could it be that there there is some sort of limit on how much water vapor air can hold, and beyond this it takes more and more heat to put water vapor into the air. In effect moisture saturated air makes water boil faster because it prevents vaporization.

If anyone could expound on this, I would be appreciative.

 

[D H]

Could it be that there there is some sort of limit on how much water vapor air can hold, and beyond this it takes more and more heat to put water vapor into the air. In effect moisture saturated air makes water boil faster because it prevents vaporization.

Yes. It's called "vapor pressure" (google that term).