Can you melt wood?

[Alan_Smithee]

@beowulff

Even in a vacuum, wood won’t melt. It will decompose first.

@Machine_Elf

not necessarily a vacuum, but any non-oxidizing atmosphere. This was an experiment in my ninth-grade science class, the destructive distillation of wood. We packed a test tube with wood splints, and stoppered it with a glass tube leading through the stopper and then passing through a cooling bath. A burner under the test tube cooked the wood; the tiny bit of oxygen in there was soon consumed and replaced with CO2 and other wood combustion products, and then - with no more oxygen available - the wood began decomposing into some interesting chemicals that distilled out as combustible liquids and gases after passing through the cooling bath.

But it never did recondense as wood. We definitely were not melting or vaporizing wood.

El_Kabong has it: every element has a melting point, but not every compound does.

Cecil did cover that, though. He explained that if you heat wood in a vacuum, you’ll vaporize the water and other volatile components first, then the remaining ash will melt, and finally the carbon will melt. I’d say that counts as melting wood, even if you couldn’t get the wood back from it! Surely if you melt every component of the wood, you’ve melted the wood, right? You wouldn’t say you can’t melt bronze because the copper and tin separate, would you?

[kayaker]

Isn’t it good?

[Anaglyph]

@Alan_Smithee

Cecil did cover that, though. He explained that if you heat wood in a vacuum, you’ll vaporize the water and other volatile components first, then the remaining ash will melt, and finally the carbon will melt. I’d say that counts as melting wood, even if you couldn’t get the wood back from it! Surely if you melt every component of the wood, you’ve melted the wood, right? You wouldn’t say you can’t melt bronze because the copper and tin separate, would you?

Yes, but the carbon atoms in wood were present as cellulose and lignin, which decompose to carbon, carbon monoxide and water before they melt. While bronze is a mixture whose components may unmix, but do not undergo a chemical transformation upon melting, the molecules in wood break up and recombine to form different, simpler molecules.

[johnpost]

melting is a physical process giving a phase transition, it is reversible.

a looser definition would be turning a solid into a liquid. heating wood would drive off water vapor (which you would have to condense to get liquid) and then drive off some organic compounds as vapor (which you would have to condense to get liquid). solid components would become charcoal if oxygen wasn’t present for combustion. either way you get a chemical change through combustion or pyrolysis.

[Michael63129]

I’m curious about where the stated figure of 9345.8 °C for the theoretical melting point of wood comes from (searching for this number and wood only gives a bunch of results which are all really the same page). They also claim that wood burns in a vacuum so…

[Tom_Tildrum]

So how much wood could a woodchuck melt if a woodchuck could melt wood?

[kanicbird]

Perhaps it would be possible to play with pressure along with or instead of with heat to try to liquify it.

also it does nto follow that melting is a reversible process for a composite material, just you could get some solid back.

[dstarfire]

To dumb it all the way down:
If you melt an object you retain it’s composition, but not it’s structure.

In other words, if you were to melt down a light bulb, and refreeze it, you’d expect to get a mass with of metal, glass ,and other stuff, not another light bulb.

This same principle applies even to very small structures, like cells, and even proteins and sugars.

[johnpost]

if something becomes liquid through pyrolysis it undergoes a chemical change. you wouldn’t loose the elemental composition but you would loose the molecular composition.

tar and charcoal don’t easily become a piece of wood again.