Does water boil at a consistent temp?
- Thread starter Woody50
- Start date
This is Dr. Aussie's go-to.
PLEASE...someone tell me the universe is 6000 years old!! THEN I'll have something smart to say!
SteveB
Well-known member
Pixie is correct about the one specific temperature. But he missed your question.
Water boils at different temperatures depending on the altitude.
"Boiling Point of Water and Altitude" https://www.engineeringtoolbox.com/amp/boiling-points-water-altitude-d_1344.html
And the reason why is due to pressure on the water. At greater pressures, the temperatures need to be higher.
At lower pressure, i.e., higher altitude, the water boils at a lower temperature.
For those of us who used to, or maybe still do go backpacking in the high country, we had to learn to follow a fairly clear instruction that water boils at a lower temperature and then we could cook our meals safely.
So.... pressure difference does change the temperature at which water boils.
Low pressure, lower temperature. High pressure, higher temperatures.
Both the links will provide you with the necessary information.
Here's one for you....
Ever want to boil water at a really low temperature?
Just take it to space.
"Water In Space: Does It Freeze Or Boil?" https://www.forbes.com/sites/startswithabang/2016/12/23/water-in-space-does-it-freeze-or-boil/amp/
Which is why I carefully specified the pressure in post 4.
"At a standard pressure of 100 kPa (1 bar) the boiling point of pure water is 99.61°C or 211.3°F. Always."
So no, Steve, I did NOT miss the question.
Not sure if you are aware of this, but space travel is extremely expensive and takes a huge amount of effort. It is not like in Stars Wars where you can just jump into your ship and head up there.
If you really want to see water boil at room temperature, just reduce the pressure in the vessel.
Cisco Qid already said this in post #10: "I have experimentally observed water boiling at room temperature in a near vacuum so obviously when you remove or vary the air pressure the boiling point changes."
If the room temperature is 20°C, reduce the pressure to 2.34 kPa, and it will boil. Rather easier than taking it to space; I have done it myself.
SteveB
Well-known member
Actually.... you did.
I do however note that you can't even take a compliment without needing to throw a temper tantrum.
Woody's original post. Part of it anyway.... the main part.
This is where I wish this forum software had gifs.
emojis just don't quite cut it.
So....
no shi8 sherlock! Thank you for stating the obvious.
Ah.... so, I have to go out and spend a lot of money on a vacuum container to reduce the pressure so I can do that.... Thanks. I'll leave that to those with the budget to do so.
As have others. I don't recall however needing to be the one who plays whack-a-mole, so they can be right.
The points I made still stands.
1- water boils at various temps, depending on the pressure. (something I actually learned at 12 yrs of age, during my first backpacking trip)
2- pressure is the determining factor of the temperature at which boiling occurs.
Water Boiling Point vs. Altitude
Elevation above sea level and the boiling point of water.
www.engineeringtoolbox.com
And since your profession is that of a PhD Chemist, I post this for you.
Methods for Computing the Boiling Temperature of Water at Varying Pressures
Abstract Boiling is an extreme form of evaporation that occurs when the saturation vapor pressure is equal to the total atmospheric pressure. This paper computes boiling temperature by four different methods and compares the results to data provided in the CRC Handbook of Physics and Chemistry...
journals.ametsoc.org
And yet I specifically stated at constant pressure.
You do know pressure varies with altitude, right?
Yeah, you would prefer to spend YOUR money on a spaceship.
Good investment Steve.
And yet you felt the need to call me out on this thread.
You words say one thing. Your actions another.
Congratulations. You have made one point twice.
Two weeks after the rest of us did.
SteveB
Well-known member
yet he asked.....
Does it? Does water boil--at any consistent altitude--at a consistent temp?
wow.... really?
You mean like at sea level the standard pressure is 1013 mb, and where I live, at 4400 feet, it's 873 mb?
Or, at 7300 feet, it's 720 mb?
Atmospheric Pressure vs. Elevation above Sea Level
Elevation above sea level - in feet and meter - with barometric and atmospheric pressure - <i>inches mercury, psia, kg/cm<sup>2</sup> and kPa</i>.
www.engineeringtoolbox.com
It was something I learned a very, very, very long time ago. Before I moved here, in 1993.
But the point was driven home for me a couple of weeks after I moved here, and was working up at Lake Tahoe.
I was using a mattox to dig out some ice, so I could install some flashing, under an old forest-service cabin. I found that after a couple of swings, I couldn't breathe. I had to stop, and it took 5 minutes to catch my breath. I then started swinging again. After 3 failed attempts, I called the boss on the radio, and he showed up a few minutes later. He picked up the mattox, and started swinging. He swung for 5 minutes steady, no problem. It was at that moment that I not only was aware of there being a pressure difference between sea level, and 6250' feet above sea level, I actually KNEW it, through personal experience.
After a brief conversation about this, we agreed that it'd just be better to wait until after the spring thaw.
Pressure with Height: pressure decreases with increasing altitude
ww2010.atmos.uiuc.edu
I further learned about it following my diagnosis with metastatic melanoma. Turns out there's another feature of the density of the atmosphere that not a lot of people understand.
That first spring we moved here I got a nasty sunburn within 15 minutes. Apparently, the densest part of the atmosphere was now below the altitude at which I was living. that extra 15% that I no longer had above me, would've allowed me to work outside in the sun for 3 hours without any concern for getting burned.
So.... Yes Pixie. I am indeed aware of this.
apparently the concept of--- it's my money, I get to spend it however I want--- is a concept that's lost on you.
Not sure why you're bothered by how I spend my money, that I earned.
But, since this IS clearly a problem for you.
why don't you just give me all your money, and I'll make sure I spend it in a manner to which I am accustomed, and then you'll feel justified that your opinions about other people's money actually mean something.
It's my money.
All I did was to acknowledge that you were correct, for that specific temp/pressure.
Apparently that was a problem for you.
Mirror please.
Well, had you not made such an issue out of the point I made the first time, I would've moved on, with the rest of my day, but it wasn't good enough for you to have left it alone.
Seems to me that it's your words and actions which have a problem here.
And?
Is there a time limit on such discussions?
If so, you might want to let forum mgmt know, because they obviously never got this memo from you.
As a side note, you might be able to raise the boiling point of water by adding cooking oil. I haven't tried it but it's worth a shot. If you can raise the freezing point of water by adding anti-freeze why not not raise the BPOW. But of course these are two diametrically opposed events.Actually.... you did.
I do however note that you can't even take a compliment without needing to throw a temper tantrum.
Woody's original post. Part of it anyway.... the main part.
This is where I wish this forum software had gifs.
emojis just don't quite cut it.
So....
no shi8 sherlock! Thank you for stating the obvious.
SteveB
Well-known member
I vaguely recall hearing something about this, but I've only ever used it to soften pasta. The boiling temp of olive oil is 356°F.
Sounds like a good science project for some high school kid or an undergrad. Is the boil point proportional to the mixtures by mass or by volume? If not then plot the curve.
SteveB
Well-known member
I'm sure someone, somewhere, has worked through this.
My use of olive oil in my cooking pasta, has been a tablespoon or so, in the water. It keeps the pasta from sticking together after cooking and rinsing.
But presumably only if you can dissolve the cooking oil in the water using an emulsifier, or convert the cooking oil to ethylene glycol.
www.reference.com
What Temperature Is the Boiling Point for Antifreeze?
Pure antifreeze, which is the chemical ethylene glycol, has a boiling point of about 388.4 degrees Fahrenheit. However, most coolants are made of a combination of ethylene glycol and water.
www.reference.com
Actually, immiscible liquids boil at a lower temperature than either of the liquids on their own.
immiscible liquids and steam distillation
Explains the background to the steam distillation of systems containing two immiscible liquids.
www.chemguide.co.uk
On the other hand, adding salt will raise the boiling point.
Boiling-point elevation - Wikipedia
en.wikipedia.org
