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Comment by xmodem | Hacker News Reader

The boiling point of water is 100 °C, and yet my shower seems to produce an awful lot of steam despite not being anywhere close to that.

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You have confused steam with small water droplets, akin to what emerges from an ultrasonic mister. If it were steam, you would be shrieking and then dead.

But it's still water, and it's still moving up and about of its own accord in the local air which is the point. That it isn't technically steam doesn't disprove the point the person you're responding to is trying to make…

The commenter's point isn't that the lead has technically been boiled, it's that, if we analogize to "steam" in a shower, I don't have to reach water's boiling point before I'm breathing in water. Does that translate to lead: i.e., even if I'm below lead's boiling point, could I be nonetheless breathing in lead vapor, or something like that? (I don't know the answer here, which would push me towards lead-free solder. I.e., I don't know if the precautions I'd take with lead would actually suffice.)

That's the reason I was being persnickety and "science-y" about terms: analogies can lead you astray. You don't know the answer here, and so your options are: 1) do some experiments, 2) reason by science, not analogy.

I have some weightlifting plates. Pure iron. Can I forego iron in my diet and just ... sit next to them? Now, by analogy, sure. Practically? Probably not.

Here's one for you: what do you think happens if you drank a glass of pure liquid mercury?

Most people think you'd die on the spot. Wrong! That mercury hasn't sublimated into mercury vapor. Instead, it barrels through your alimentary canal like a shot and was used to treat constipation, of all things. It is poorly absorbed by digestion and just runs right through you.

Phase changes matter for these things.

No, soldering doesn't send streams of liquid solder through the air. And if an occasional drip of solder does splash, it is so heavy, and has so much surface tension, that it doesn't go far and doesn't stay in the air like water droplets do.

I thought everyone did the experiment of leaving a saucer of water out and seeing it evaporates over time, despite being significantly lower than 100c.

And "Steam" is wooly term for high enough density of water vapor that you see condensation - often caused by higher temperatures in the majority of cases people experience it in day to day life. So it doesn't really have a precise definition. At what temperature point does "mist" become "steam?" What %age of the volume of air needs to be water vapor? If you lowered the pressure water "boils" at a lower temperature - is that still steam?

That first question, it is 100C at STP. Second question, enough to make you have a second or third degree burn. Third question, yes.

Good point. Also, steam is invisible. What we see - e.g. from a boiling kettle - is condensation.

We solder at 200°, which is 1500° below the boiling point and 23% of it. You shower at probably 40°, which is 60° below the boiling point and 84% of it. Because vapor pressure is typically an exponential function of temperature the absolute difference (1500°) is the more important measure here. If you were showering at -1500° you would have a point, but absolute zero is only -273.15°, so you can't.

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