I had an email discussion about this with Dr. Robert Wolke, a chemistry professor who used to write a column about food science, and also has written some books. I cannot now find the email but he had referred to steam as the visible stuff. I wrote him saying I thought steam was the invisible gas phase of water of 212F, and water vapor was the visible suspension of droplets in the air. He told me I had it backwards.
Atomizer, atomizer, you’re an atomizer baby
I hate when my kids play too much pop music on the radio.
Originally Posted by Chief Pedant
There’s no chance you are mixing up “steam” and “water vapor” is there?
I looked up the origin, of course, before posting.
There is a nearly irresistible temptation among the educated to hijack ownership of the “official” definition of a word, particularly where the educated Arbiter can back up the claim with a scientifically-based definition.
In the case of “steam,” though, the polloi coined it first–perhaps as long as a millenium ago for the original word, if my casual search was accurate. I doubt the original users of the word made the distinction that Chronos did, so it seems to me the word, as used in Post 2, should stand.
If popular and undereducated use corrupts an original, more precise definition, that’s one thing. But if science comes along and embraces an existing word, attaching to it a new, more nuanced definition, correcting the common (but original) usage is on shaky ground, is it not?
-12F here in Saint Paul right now. Sauce pan with about 3/4 of an inch of water at a rolling boil. Throwing it up in the air produced…rain. Well, a bit of it turned into a cloud, but the majority went up water, and came down water.
Well, the words themselves are fine, but picking consistent definitions of words and sticking with them makes it a lot easier to teach other, physically significant, concepts. For instance, if a “steam pipe” leaks, it can produce an invisible but very dangerous jet of high-temperature gaseous water, but this is harder to explain to someone who has it fixed in their head that steam is visible. We could, of course, define “steam” to be the visible stuff and exclusively use “vapor” for the true gaseous phase, but then we’d have to go and rename steam pipes “vapor pipes”, and the like.
To lower the temperature or change the state of matter takes time, temperature differance, and contact area. (It should be three "T"s sorry but I am coming up with a blank for contact area, too many years)
Example 1 gallon of water in a gallon can is placed in an -25 degree enviorment. A second gallon of water divided between 50 small cans is placed in the same enviroment. The second gallon has a larger total surface area and will freeze faster.
A pan of water thrown up in the air will break up into drops of water if there is enough time before the water hits the ground it will freeze.
A pan of hot water thrown up into the air will break up into smaller drops and water vapor clouds (hot water has less surface tension). Creating larger surface areas. They will drop slower so both a increase of time and contact area.
BREAKING NEWS: I just threw a pan of boiling water out of the door and it didn’t quite work. It did make an impressive steam cloud and some little ice balls, but the bigger drops came down as water. I also drenched the upstairs neighbours’ balcony. Oops. -32 C here right now.
No, it’s not true. Sure you’ll get a nice puff of fog-condensed-water-vapour/cloud-like shit, but the majority of the water you threw up will simply fall in the liquid state onto the ground (which is almost certainly covered with snow), melt and sink into that snow, and turn to ice within a couple minutes out of view. You won’t notice it due to either the distraction of the fog, the fog blocking your view of the rest of the falling water, or your need to get back inside before investigating what you think you saw properly.
It’s simple to test for yourself - go outside during appropriately cold weather, unzip your fly, and take a piss. Shake your spout around to make the stream all small drops if you like… you’ll simply make a nice little yellow pattern of liquid water dribbling into the snow, not mini ice cubes or yellow dust. Sure urine has a slightly lower freezing point than pure water, but the much lower initial temperature more than compensates for that (and the reduced “air time”). Besides… who’s boiling distilled water anyways? Throwing hot water into cold air is simply a poor man’s magician’s trick… you want to see it all freeze before it hits the ground so you do. But it doesn’t. I’ve taken many leaks at -35ºC.
You’ve just stolen my distinction between “water vapor” and “steam.” Water vapor’s the invisible stuff. Steam is little droplets of condensed liquid water suspended in the invisible water vapor. Now my life is ruined.
-20F this am, so I did a repeat of my above study. This time the steam cloud (or water vapor, or pixie dust, whatever the hell you want to call it) was much larger. But still not as impressive as other times I have done it.
[minor hijack] Dr. Wolke came for a lecture (“Substance Abuse in the Kitchen”) at a recent networking event hosted by my employer. I got to speak briefly with him afterward. I forget how the subject came up, but he said he is a fan of the Straight Dope. [/minor hijack]
Sorry, but you’re completely wrong, your urine notwithstanding. Urine contains proteins and sugars and is not anything like plain old water. And -35C is not nearly cold enough for this particular process to occur. -35F is a different story, and at -50F, odd things start to happen: oil freezes, gasoline turns to jelly, and yes, water thown into the air does not reach the ground as visible liquid.
According to the folks on Mt Washington the water needs to be near boiling for it to work successfully. Lower temps of the water (below 200) doesn’t work as well so that may explain why it doesn’t work with piss.
