.... stick your hand in it. Assuming an ambient air temperature of 70° F:
If it feels pleasantly damp, it's water vapor.
If the skin comes off, it's steam.
more malarkey - as someone who's spent the last 30+ years running a food processing plant, I can tell you that the 'vapor' coming off very hot water below 212* will NOT feel "pleasantly damp"
as noted above, steam is vapor, generated by the phase change of water that happens when boiling under pressure - the visible vapor from a rad is not steam
Bill
