Someone please explain...

[lechee]

Do you have room in the bottom of your Bator?

 

[Huny]

Think of it like a Fondue Pot (or a boiling pot of water). When cooking and there is a lot of water in it, the fire will keep it at a steady boil. As you eat the cheese out, the remaining cheese gets hotter and hotter. When you have less water in there, the temperature can heat the water faster and evaporate it faster. Yes, humidity is about surface area, but it's also about evaporation.

 

[rhythmicgoldfish]

my guess is surface area, it looks as though you have a sponge that sits in the pan of water, when the tub is full only a little bit of the sponge is touching the air because most of it is submerged but when the water is low the sopping wet sponge provides at least an extra foot of wet surface area if not more (after all every pock mark and hole in the sponge provides extra surface area)