15

We have a word called evaporation for liquid turning into vapour. Is there a word for something turning from gel to liquid?

The thing is that I have a plant "Aloe Vera" and it has a gel substance in it. But if you pluck it and let it rest for few days, the gel turns into liquid.

Is there a word for it?

  • 5
    Deliquesce: (Of organic matter) become liquid, typically during decomposition. – Joe Dark Oct 21 '15 at 19:35
  • Is there a precipitate formed, or does all of the gel seem to have turned into a liquid? – M.A.R. ಠ_ಠ Oct 21 '15 at 20:24
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    @JoeDark I don't think that's a good choice, for two reasons. First, it's usually used with the meaning it has in chemistry, which is to absorb moisture from the air, and that's not what's happening here. Second, outside chemistry, it's a very rare word so it's not likely to be understood. Anyone who's familiar with the meaning from chemistry will misunderstand you; anyone who isn't, probably just won't understand. – David Richerby Oct 22 '15 at 7:52
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    @JoeDark, David, Thirdly, not all gels are organic, so it's wrong on a technical level anyway. (Nice word of the day for me though!) – James Webster Oct 22 '15 at 11:04
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    @JamesWebster Sure, though I don't think it's a technical word, in that sense. Even if it is, using technical terms figuratively in a non-technical sense is fairly common. – David Richerby Oct 22 '15 at 11:41
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The general technical term for a solid or gas becoming a liquid is "liquefaction" (the verb form of which is liquefy) - but it's something that I'd say is probably mainly used in engineering/materials science contexts for this.

Since a gel is classed as a solid (technically, a solid with liquid dispersed through it), I'd say it's fine to refer to its liquefaction (certainly in any casual context) as "melting", same as you would any other solid.

10

There are two answers suggesting melt. This is not a bad choice, and in many circumstances it is the one I would use. It would be widely understood and wouldn't raise many eyebrows.

That said, melt carries at least a little hint of a sense of temperature changes. (I think butter melts because the colloidal fats actually do change from solid to liquid with temperature changes.)

@JezW mentioned the noun liquefaction. I agree that in the noun form it is technical jargon rarely heard outside of science/engineering. I believe the conjugated verb form, liquefy/liquefied, is used more widely. (var spelling: liquify)

If the gel turns to a liquid completely in the absence of temperature changes, I would use liquefy.

If you squeeze a corn-starch and water mixture it will harden in your hand, but if you relax your grip it will liquefy again.

I left a jar of mayonnaise in the fridge for a year. When I opened it, it had completely liquefied. Do you think it is safe to eat?

If you don't use your hand sanitizer within a month or two, it might start to liquefy.

In the later two cases the implication is that despite stable temperatures, something else has caused the structure to break down - the solids spread through the liquid are settling, or are simply falling apart.

Evidence for this word being used outside of a scientific context: The song "Liquefy," by the band The Servant: youtube link to music video


TLDR; I would consider liquefy/liquefaction to be the general term. It could occur due to melting, decay, decomposition, sedimentation, deliquescence, etc. In casual circumstances, people might use melt for any of these, but it has connotations of temperature change, and will sound strange if people know one of the other mechanisms to be at work. Liquefy is widely understood, and always means turns into a liquid, whether by chemical, thermal or mechanical processes.

  • Huh - Sublimate used to be more widely used : books.google.com/ngrams/… – Adam Oct 21 '15 at 17:00
  • Liquefy it is; they have to expect correction from the nitpicky me if they say melt. :) – M.A.R. ಠ_ಠ Oct 21 '15 at 20:55
  • @inɒzɘmɒЯ.A.M - Do you know why Sublimate might have been so much more popular mid-century? Was there some field of research into sublimation that was just opening up? – Adam Oct 21 '15 at 21:10
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    @Adam It peaks at the beginning of the 20th century, not the middle; and most of those hits are medical uses of "corrosive sublimate", an old name for mercury bichloride, used as a topical antiseptic. – StoneyB Oct 21 '15 at 22:35
6

To deliquesce is to absorb moisture from the air. That is not what your aloe is doing. The gel is a colloid of protein and water. The protein chains are breaking down. I would call that 'decay'. Thixotropic colloids become more slippery under shear, because the chains get aligned when they are dragged past each other. That is what happens when you pinch the fresh aloe.

  • It seems bacteria are responsible for the decomposition of the polypeptide chains. I believe the part "sol->liquid" is indeed "liquefaction", however decomposition (not "decay") is spot on and more scientific. (Note that everyday life usually doesn't refer to what happens 'behind the scenes', rather what is observed) – M.A.R. ಠ_ಠ Oct 21 '15 at 20:58
5

There are common1 words for all the transitions between the common states of matter:

Solid  -> Liquid   = Melt
Solid  -> Gas      = Sublimate
Liquid -> Gas      = Evaporate / Boil
Liquid -> Solid    = Solidify / Freeze
Gas    -> Solid    = Desublimate / Sublimate [2]
Gas    -> Liquid   = Condense

The problem is that gel is a colloid. That is, it has two parts, in two states, one spread throughout the other. In this case, there is a solid spread throughout a liquid.

Since the same is true of butter, (solid fat spread through water), and butter melts, I'd be happy to use the word melt for a gel too.


1. Ok, sublimate isn't exactly common, and this list isn't complete, just provides some options.

2. See comments.

  • 3
    Gas --> Solid is also (perhaps more commonly?) referred to as deposition. And freezing is a decent synonym for solidifying. – Adam Oct 21 '15 at 16:14
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    @Adam, huh, I've never heard of deposition in that context. I only know the "ousting" and legal contexts. Can't believe I forgot about freezing :P – James Webster Oct 21 '15 at 16:16
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    @James Webster -- "Chemical Vapor Deposition" (CVD) is one of the choices a manufacturer has for applying a coating to a material. Sometimes the "coating" is the entire material, which is then removed from the substrate it was deposited on. You probably use some products that were made (or coated) by CVD on a daily basis. – Jasper Oct 21 '15 at 16:22
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    Deposition is common; however, sublimate is indeed common in a theoretical chemistry context. If a colloid relaxes though, we'll call the process "sedimentation". – M.A.R. ಠ_ಠ Oct 21 '15 at 20:54
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    "Thaw" and "melt" are not synonyms at all. After thawing, an object (usually food or plants) is typically still solid, though the ice in it has melted – Fabio Beltramini Oct 21 '15 at 23:31
2

Thixotropy is defined to be the gel -> fluid behavior you describe.

Another answer mentioned it but settled on a different word.

  • 4
    Thixotrophy is used for a gel that temporarily turns to liquid when subjected to shear stress, then reverts back to a gel when left alone. That may not be what the O.P. is looking for. – Adam Oct 22 '15 at 19:54
  • What is the verb form of "thixotropy"? – Jasper Oct 22 '15 at 23:31

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