I put some water in a teakettle. I put it on the stove.
I turn on the burner, on high. After a while the water in the kettle boils. The steam from the boiling water entirely fills the kettle, pushing out *all* the air. The steam is rushing out the little hole (making an awful whistling noise), *and* the kettle itself is *entirely* filled with steam. The pressure in the kettle is at 1 atmosphere, give or take a few millibars. It's all at 100C, give or take a degree .... except for the bottom surface of the kettle, which is quite a bit hotter where it contacts the burner. I leave it on the stove and go take a nap, ignoring the whistling noise. After a while, all the water boils to steam. The kettle is still filled with water vapor, of course! But now there's no liquid water left. The stove is still on high, and after a while the bottom of the kettle starts to glow a cheery red. The kettle is still filled with water vapor -- "dry steam" -- and the pressure inside is still 1 atmosphere, give or take a few millibars. What temperature do you suppose the steam inside the kettle is at? Could this be -- gasp! -- an example of superheated steam at 1 atmosphere?? Darn right.
