Is one molecule of water wet?

Is one molecule of water considered to be wet?

(I do not know if this question has already been asked. I did research it on your site, but to no avail. If I just simply missed it please send me a link to the thread and disregard my question.)


You wouldn’t be able to feel one molecule of water, so it wouldn’t feel wet. By itself it wouldn’t have surface tension, and would probably be battered about by the molecules of what ever substance it was surrounded by, so wouldn’t flow in a watery wet way, so I’d say no.

That question is in large part theoretical because if other molecules of water are present then you have to consider the whole fluid, and it’s highly unlikely you’d find a single isolated molecule of water. But if I were to take a stab, I’d say a single molecule of water constantly fluctuates between being dry (a gas) and wet (sort of a liquid in that it could adhere to something).

Wetness describes the tendency of a liquid to adhere to a solid. The definition of liquid depends on the context you’re talking about, but it is generally characterized in terms of large amounts of molecules (unstable or absent internal crystalline structure, surface tension, adhesion, cohesion). None of these really apply to a single molecule except maybe adhesion. Moreover, water at room temperature is going to exist at some sort of equilibrium between liquid and gas.

This might be more of a philosophical question. How many molecules of water do you need before it’s wet? “Wet” is not a quality of water, it is a quality of an object that has water on it. For example, the cohesion of water to itself is greater than its adhesion to something like wax, so wax doesn’t truly get wet. But for a surface that can get wet, one molecule is enough to say that it’s wet.

Nobody knows.

I don’t think it’s entirely philosophical, is it?

There are water molecules around me right now - some of them are grouped together in the glass on my desk. There are others in the air around me. The group of them in my glass feel wet, the spaced out ones in the air don’t.

So I’m going to go with no, in the real world, isolated water molecules don’t feel wet.

It’s as wet as the sound of one hand clapping is loud.

It’s wet as a single lego is a building project.
Could use that single molecule of water to wash just one hand?

Actually, can one molecule of anything be defined as a solid, liquid or gas? Isn’t a materials state dependent on the configuration of a bunch of molecules?

I say it would be wet provided it was soaked into something else.

With 1 molecule you could observe it adhering to a surface, which technically could be considered wet. If you had 2, then you could observe whether they tend to cohere more to each other or to something else. If I spray water on a vertical surface of wax, the wax does get wet. The water molecules have greater cohesion to each other, so they form beads rather than a film, but the beads definitely do adhere to wax due to intramolecular forces, which is wetness.

Also, wetness can be an intrinsic characteristic, it isn’t entirely relative to the contact surface. Water is considered to be “wetter” if soap is added to it, this is why fire trucks add surfactants to water used to fight fires (called a “loaded stream”).

Is one atom of copper ductile? Is one atom of gold malleable? Is one molecule of TNT explosive? Is one molecule of CO toxic?

Not CO, but some molecules are:

Depends how you define the word “wet.” “wet” could be defined different ways for different purposes.

True, of course, and by analogy, I didn’t ask “is one atom of uranium radioactive?”, because of course the answer is “yes, once, at an indeterminate time” (after which it may well still be radioactive, but not uranium any more). But in general the toxicity of CO is down to its ability to convert haemoglobin into carboxyhaemoglobin, which it does very effectively but, since this locks up the CO as well, not to any harmful effect unless you have enough of the stuff to taint an appreciable proportion of your haemoglobin.

From here:

As has been said, since there’s only one molecule, there’s no surface tension, so there’s no wetting. If there’s no wetting, it’s not wet.

Of course, the litmus test would be if somehow you could *feel *its wetness. Now if your finger were reduced to one molecule . . .

I have nothing to add here, but am I the only one that thought of **They Might Be Giants’ ** “Particle Man” here?

Is he a dot, or is he a speck
When he’s under water does he get wet?
Or does the water get him instead?
Nobody knows, Particle Man

you weren’t :stuck_out_tongue:

Maybe “damp”?

Nonsense. We only need to define what “wet” means, and compare the effects of one molecule of water to that definition. I would define “wet” as being the characteristic that water behaves like a fluid continuum and acts as a weakly polar solvent, which is really just a more formal way of stating what Staggerlee and Pygmy Rugger have already said. Since one molecule is discrete, it can’t be considered a continuum or treated like a fluid, and while technically it will “dissolve” another molecule out of a substance, for all practical matters one molecule of water isn’t going to be noticed. In fact, if we arbitrarily define a drop of water to be on the order of 1 gram, it’s going to take sextillions of water molecules all bonded together to make something noticibly wet.

So no, one molecule of water isn’t “wet”. “Wet”, in a practical sense, is where you can see or feel a fluid continuum of water.