THE CLOUD ABOVE A BOILING KETTLE IS STEAM OR COLD WINDOWS "STEAM UP"
WRONG!! but you can just about get away with this!
STEAM is really water vapour which is water in its gas state.....it is invisible.
If you look carefully at the area just above the spout when a kettle is boiling steadily you will see that it is totally transparent and colourless. (PLEASE NOTE..BE CAREFUL HERE THE STEAM
CAN CAUSE A VERY NASTY SCAULD SO DO NOT GET TOO NEAR OR TOUCH IT). after a few centimetres it seems to form a cloud. This is caused because the water vapour meets the cooler air and so some water condenses
and forms tiny water droplets..all these droplets make up the white cloud. Although this is not technically "steam" use of english probably allows us to use the name. Note also that the cloud seems to have an end to it even though
the kettle is still boiling, this is because the warm tiny water droplets are re-evaporating into the air.
after a while you will find the windows (which are cool) will "steam up". When the warm water vapour meets the cool window some of the water vapour
condenses back into water droplets on the windows as they remove heat from the water vapour.
(thanks to Ben Daglish for fine adjustment to the explanation)