Submitted by cheese_grater_man69 t3_11d010c in explainlikeimfive
Comments
tdscanuck t1_ja620w3 wrote
Have to be a little careful here...lots of carbon-based organic compounds melt. Like pretty much all plastics, fats, waxes, etc.
It just happens that the main compounds in wood (lignin, cellulose) are heavily cross-linked and undergo thermal decomposition into things that burn before they reach melting temperature under normal conditions.
Lirdon t1_ja6298d wrote
You’re absolutely correct. My bad.
cqpa t1_ja683vn wrote
I feel like we still haven't arrived at an "explain like I'm five" version yet, though?
So maybe something along the lines of... so there's a lot of important things that are different between wood and metals. As u/Lirdon said, metals are just raw elements (i.e. silver, nickel, etc.). The atoms in metals form a special type of bond with each other that's different from the bonds that we see in organic stuff like wood. The type of bonds formed by metals lends itself really well to going evenly from a solid into a melty liquid when you heat it.
Wood is a mix of many types of organic, non-metal compounds. The bonds that these atoms in these compounds form tend to be much, much stronger.
When non-metal stuff with those stronger types of bonds gets heated, sometimes it goes nicely from being a solid to a liquid (like the plastics and waxes that u/tdscanuck mentioned). But sometimessss things get real spicy instead. In the case of wood, the compounds completely break apart into ash, tar, and the CO2 gas. Metals don't really have the option to "break apart" into other things since the nickel, copper, etc. atoms are already in their most basic form.
Maybe? Hopefully the people who actually know chemistry can come fix this lol
Edit: apparently metals can also burn but there's a bunch of reasons when metals common forms we see them don't very often. https://www.wtamu.edu/~cbaird/sq/2018/02/18/why-dont-metals-burn/
PerturbedHamster t1_ja6s9ef wrote
And lots of metals do burn, even before melting. Magnesium burns intensely. This table lists a bunch more.
Jetboot t1_ja6cy10 wrote
Melting temperature and burning temperature are different. Wood actually does have a melting temperature, but it's way past the melting temperature.
Similarly, metals generally have a burning temperature that is well past the melting temperature.
In the middle are plastics with melting and burning temperatures that are close together.
And then there are ceramics. It is technically possible to melt them, but technically they are already burnt... ceramics are weird.
bbqroast t1_ja6iwzw wrote
The molecules in wood are super big organic (carbon, hydrogen, oxygen, etc) molecules that can't really "flow" around each other in a liquid.
If you got them hot enough to flow like that, the molecules would rip itself apart - either burn (in the presence of oxygen) or sublimate into gas.
LogosPlease t1_ja5z9oc wrote
The carbon bonds release a lot of energy when exposed to a little heat and oxygen. Metal will melt after you put intense amounts of energy into it because it doesn't have carbon or carbon bonds with energy. If you take a lighter to (most) metals they will not experience any physical changes. Carbon can melt but it has to be at incredibly high temps to do so.
Lirdon t1_ja5znp3 wrote
Wood is not a basic element, its a lot of organic material made of carbon, and carbon, in general doesn’t melt, it sublimes. While metals have a melting point that is achievable, carbon melting point is like 3,5K degrees and before that it combusts and becomes smoke.
EDIT: I was corrected, there are carbon based organic compounds that melt, like plastics. But it so happens that compounds in wood do not. Just for clarification.