In a surprising finding, light can make water evaporate without heat
In a surprising finding, light can make water evaporate without heat
At the interface of water and air, light can, in certain conditions, bring about evaporation without the need for heat, according to an MIT study.
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Uh, I'm surprised.
I learned this in school more than a decade ago.
Did my teacher accidentally lied the truth?
Light is energy. This isn't surprising to me at all.
The energy transfer to evaporate water is the heat. This is specifically without heat.
They proved more water was evaporated than the heat applied to the water.
The theory being the light knocks away water particles at the surface of the water without heating them.
So, in fact, water will evaporate without heat because of the lack of equilibrium between air and water, until the air is wet enough for the process to stop.
Discovering that light vaporise water is not the same as discovering that water vaporise itself without heat. It is an interesting discovery nonetheless.
Up to 3 times more water evaporated than heat energy the light could supply.
It's pretty massive if true.
It's still silly.
Imagine commenting "it's still silly" in a science focused community.
I'm a scientist, you big silly.
What does that even mean?
That's literally not possible. It may be heat that we don't have sensitive enough equipment to detect but light is energy and it hitting the water will release heat.
I mean that's literally what this study has shown. So it is indeed completely possible.
I don't think you have the grasp on things that you think you do. I'm not in the mood nor do I have the time to have a beginners class on this so I suggest you do some reading on your own and learn how to analyze things and come to your own conclusions. Way way too many studies are straight up faked at worst, at best they are tweaked and results that say something different are thrown out or ignored.
By this logic, when we heat up food or drinks in the microwave we are not using heat at all. We are in fact generating heat as the water molecules are excited by the energy in the radio waves being transmitted towards whatever is in the microwave. For those who may not know, radio waves are just light we can't see because our eyes don't have whats needed to see them.
You know what. Ignore everything I said above and keep on keeping on. Stay ignorant and full of yourself. See how far that gets you in life.
I hope you lack the time because youâre setting up your own study. This one was set up due to previous observations of rates of evaporation double or greater than those understood to be mathematically possible. Hell of an equipment error. It also observes a difference in the rate of evaporation under different colors of light, with the highest rate of evaporation occurring under green light, which you would probably also deem impossible, since color has nothing to do with it and green isnât even the most energetic wavelength. An MIT professor, a postdoc, and four others hang their hat on these results, and the reality of this phenomenon. rdyoung disagrees with them in a comments section on an obscure forum. Which source might be more credible?
You also definitely don't understand what I or the study is saying. Not surprised here at all.
Again, as I said. Maybe we don't have the tech to read the miniscule amount of heat in a photon of light or the heat generated as the light excites the water molecules, that doesn't mean that heat wasn't a part of it.
Yet another one who has no idea or grasp of the concepts at play here.
Just like reddit, I thought a sub such as this would have a smarter community but once again you lot proved me wrong and showed me that no matter how dumb I think people can be, they can always surprise you with the idiocy.
I'll leave you with a quote from Harvey Danger.
Been around the world and found That only stupid people are breeding.
Just like Reddit you're being an absolute asshole for no reason.
Lighten up. This is no way to have a productive discussion. If you aren't in the mood, then maybe you shouldn't be commenting right now. Take a breather. We all have bad days. Hope you feel better.
You replied to a fairly accurate summary of the postulated explanation of an observed phenomena by saying itâs literally impossible. Either the study is faking its* data, or the study has real data but you donât like the way definitions are playing out here. Youâre arguing for both, because itâs really important that this study is wrong, because you donât like it. But it canât be both. Letâs assume PNAS didnât publish a completely fraudulent study about a made-up phenomenon.
The thermal heat that is being transferred is what causes evaporation. Thatâs the historical understanding. Yes? Energy in, energy out. 1:1 ratio, everything is conserved. But itâs evaporating twice as fast as that measured heat transfer explains. 1=2? Thatâs not right. Saying âitâs just more heat that you canât measureâ doesnât make any sense, because youâre claiming that 1.0004 = 2. Itâs a new process. Yeah, something happened on a molecular level and there was probably heat transfer. But on a completely different scale than the known process of evaporation through actual âmacroâ heat transfer. So itâs not the fucking same.
Again, the green thing. If evaporation is caused only by previously understood processes of heat transferâmore energy is more heat transfer is more evaporationâthen why does a less energetic green light produce more evaporation than a more energetic blue or violent light?
âThe researchers tried to duplicate the observed evaporation rate with the same setup but using electricity to heat the material, and no light. Even though the thermal input was the same as in the other test, the amount of water that evaporated never exceeded the thermal limit. However, it did so when the simulated sunlight was on, confirming that light was the cause of the extra evaporation.â
Sorry to steal so much of your time, but if youâre not fucking whatâs so damn important
Don't feed the troll.
First, being rude makes you look like you don't know what you're talking about. Condescension in technology and science is very 'last century'.
Second, you're right. This article is a bad translation at best. If the light interacted with the water in any way that produced motion and caused evaporation, that motion IS heat.
They probably mean to say that they can evaporate water directly with light without having to use a heating element or something non-water to absorb the light. That's my best guess at translating a poorly written article at least.
From the abstract: âWe interpret these observations by introducing the hypothesis that photons in the visible spectrum can cleave water clusters off surfaces due to large electrical field gradients and quadrupole force on molecular clusters.â
The commenterâs interpretation of the summary was pretty close to the language Chen used.
To be clear, this article is written by an English native speaker who is summarizing a study written in English primarily by a man whoâs been at U.S. universities for three decades. Unless you meant it was a bad summary, which I donât think it was, but thatâs opinion.
No they literally state more water was evaporated than heat energy from the light could do by up to 3 times.
That's assuming some definition of heat that requires light absorbtion. This is still heat, because all motion of atoms is heat.
Oh look, another snowflake who reads factual statements as being rude. Fuck off with that shit.
The above said, thank you for being one of the few who actually gets it. There is heat everywhere there is light even if we can't detect it with equipment. The light exciting the water molecules generates heat, this is a fact that could only be argued with by those who think birds aren't real and/or that JFK will rise from the dead and bring along Lincoln as his vp.
Insulting others for pointing out your mistakes makes you look like a child. Graceful acceptance of feedback is a sign of maturity.
I realize that it's a common autistic trait to need to be correct and have little patience for those who don't understand, but take it from my personal experience, training yourself to not do that will improve your life significantly.
snowflake
Ah you're just a giant insufferable douche. Got it.
Haha, what a nice trolling attempt!
Yeah that's the part that confuses me....how does one transfer energy to something without generating any heat?
They explain that in the article. Light barely gets absorbed in water, which is why you can see several meters deep in water. Only the absorbed part can turn into heat.
They measured an effect that partly evaporates water more efficiently than the heat influx can. The theory mentioned in the article is, that light directly knocks out water molecules at the water/air surface boundary. The measured effect was the most effective with light of a green wavelength
Heat doesn't really exist at an individual particle level, it only describes the average kinetic energy of a large number of particles. "Normal" evaporation occurs because all the water molecules are jiggling around fast enough that sometimes some get knocked off at the top and fly away. The theory from this paper says that light can strike a single water molecule just right that it breaks off without help from the others.
Saying this is "without heat" means that the light isn't simply increasing the average kinetic energy at the top of the water and speeding up the rate of "normal" evaporation. They think it's specifically acting on a single molecule at a time.