# Technology on a planet with only the 25 essential elements for life **URL:** \ **Category:** Factual Questions\ **Created:** [December 17, 2015, 2:43am UTC](https://boards.straightdope.com/t/technology-on-a-planet-with-only-the-25-essential-elements-for-life/740657 "2015-12-17T02:43:42Z")\ **Posts on this page:** 20\ **Page:** 3
**Author:** ![the\_diego](https://avatars.discourse-cdn.com/v4/letter/t/7bcc69/32.png) [@the\_diego](https://boards.straightdope.com/u/the_diego)\ **Post date:** [December 18, 2015, 9:16am UTC](https://boards.straightdope.com/t/technology-on-a-planet-with-only-the-25-essential-elements-for-life/740657/41 "2015-12-18T09:16:36Z")
Not, not for that site (meaning nonclayey soil for forest growth.) What I do know is clay content, or soil texture, hardly matters in allowing tree growth. What matters are things like water, aeration, non-compaction, ph, etc. You can have ideal conditions for tree growth without clay. ---
**Author:** ![MrDibble](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/mrdibble/32/114_2.png) [@MrDibble](https://boards.straightdope.com/u/MrDibble)\ **Post date:** [December 18, 2015, 11:24am UTC](https://boards.straightdope.com/t/technology-on-a-planet-with-only-the-25-essential-elements-for-life/740657/42 "2015-12-18T11:24:54Z")
> [@the\_diego](#): > > You can have ideal conditions for tree growth without clay. Then it would be trivial to point to just such a forest. ---
**Author:** ![MrDibble](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/mrdibble/32/114_2.png) [@MrDibble](https://boards.straightdope.com/u/MrDibble)\ **Post date:** [December 18, 2015, 12:19pm UTC](https://boards.straightdope.com/t/technology-on-a-planet-with-only-the-25-essential-elements-for-life/740657/43 "2015-12-18T12:19:11Z")
> [@coremelt](#): > > If we ever manage to create them, elements in the island of stability are still expected to be extremely radioactive with a half life between one-day and one-year. We’re not going to be seeing any new elements that are stable even over a human lifetime. Oh, true enough. ---
**Author:** ![Riemann](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/riemann/32/3133_2.png) [@Riemann](https://boards.straightdope.com/u/Riemann)\ **Post date:** [December 18, 2015, 10:39pm UTC](https://boards.straightdope.com/t/technology-on-a-planet-with-only-the-25-essential-elements-for-life/740657/44 "2015-12-18T22:39:52Z")
This has been fascinating. Thanks MrDibble - I had no idea of the significance of Al in clay minerals. I’ve been trying to understand just why. Al is of course the smallest cation with the highest charge, but I can’t find any straightforward explanation of how this relates to the fine granularity of the clay minerals; or perhaps it relates to capacity of the grains to coordinate water molecules and hydrate? Do you know if Al is present in virtually all clays because of its abundance, or is it essential to impart claylike properties? If Al were absent but other small cations were more abundant, could they replace it in principle, to give clays with similar properties? ---
**Author:** ![dracoi](https://avatars.discourse-cdn.com/v4/letter/d/90db22/32.png) [@dracoi](https://boards.straightdope.com/u/dracoi)\ **Post date:** [December 18, 2015, 11:35pm UTC](https://boards.straightdope.com/t/technology-on-a-planet-with-only-the-25-essential-elements-for-life/740657/45 "2015-12-18T23:35:45Z")
I don’t think the presence of clay in soils is such a big deal when discussing a hypothetical planet. Even if we can’t find a single tree in Earth’s forests that could survive without clay, that means nothing for a planet that evolved from day one without clay materials. Without clay in the soil, you’d see plants adapt to soils without clay. Perhaps they’d even decompose in a very specific cycle that provides the missing clay-like features of the soil. In fact, that’s pretty much what already happens in places like the forests of the Pacific NW. You have to really dig to hit a layer of dirt that contains clay/aluminum compounds and only the trees themselves are down that deep. Everything else in the forest is growing what’s basically an acidic mulch of moss and fallen debris. It’s not good agricultural land from a human food perspective, but we’re still talking about Earth-based plants adapted for Earth-based soils. ---
**Author:** ![MrDibble](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/mrdibble/32/114_2.png) [@MrDibble](https://boards.straightdope.com/u/MrDibble)\ **Post date:** [December 19, 2015, 1:15pm UTC](https://boards.straightdope.com/t/technology-on-a-planet-with-only-the-25-essential-elements-for-life/740657/46 "2015-12-19T13:15:31Z")
> [@Riemann](#): > > This has been fascinating. Thanks MrDibble - I had no idea of the significance of Al in clay minerals. I’ve been trying to understand just why. Al is of course the smallest cation with the highest charge, but I can’t find any straightforward explanation of how this relates to the fine granularity of the clay minerals; or perhaps it relates to capacity of the grains to coordinate water molecules and hydrate? Do you know if Al is present in virtually all clays because of its abundance, or is it essential to impart claylike properties? It’s not _essential_ to providing the particular sheet-like structure of clays (also the micas) - alternating layers of Si-O tetrahedra and Al-O octahedra. Mg can play this role as well, like in talc or sepiolite. But neither of those has the properties of the Al-clays - sepiolite makes lovely meerschaum pipes and you can carve bowls out of talc soapstone, but neither is plastic the way actual clay (kaolinite, montmorillonite-smectite, illite) is. The fine granularity comes because those sheets are held together with some relatively weak Van De Waals and being sheets, allow for more breaks in the layers themselves. There are differences between the structures you get with Al (clays) and without (the Mg serpentines) and between the different ratios of Al to Si layers (1:1 vs 2:1 clays) and how those reflect the capabilities of the crystal to absorb other elements in their structure either ionically or through replacement. > [@](#): > > If Al were absent but other small cations were more abundant, could they replace it in principle, to give clays with similar properties? Like I said, Mg forms similar structures but they don’t have the same properties. ---
**Author:** ![MrDibble](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/mrdibble/32/114_2.png) [@MrDibble](https://boards.straightdope.com/u/MrDibble)\ **Post date:** [December 19, 2015, 1:22pm UTC](https://boards.straightdope.com/t/technology-on-a-planet-with-only-the-25-essential-elements-for-life/740657/47 "2015-12-19T13:22:25Z")
> [@dracoi](#): > > I don’t think the presence of clay in soils is such a big deal when discussing a hypothetical planet. Even if we can’t find a single tree in Earth’s forests that could survive without clay, that means nothing for a planet that evolved from day one without clay materials. Without clay in the soil, you’d see plants adapt to soils without clay. Perhaps they’d even decompose in a very specific cycle that provides the missing clay-like features of the soil. Then you’re into absolute speculation that’s outside the scope of the OP’s question as posed, IMO. Anything is possible, I guess - 25-element world could evolve biological computers and naturally-occuring carbon-fibre space elevators, if you like. > [@](#): > > In fact, that’s pretty much what already happens in places like the forests of the Pacific NW. You have to really dig to hit a layer of dirt that contains clay/aluminum compounds and only the trees themselves are down that deep. Yes, but without that layer and its physical properties, I doubt you’d get anything like a tree to stay standing. Podzols aren’t pure sand anymore than most other soil types. Pure sand isn’t great for supporting tall structures. > [@](#): > > Everything else in the forest is growing what’s basically an acidic mulch of moss and fallen debris. It’s not good agricultural land from a human food perspective, but we’re still talking about Earth-based plants adapted for Earth-based soils. No-one’s questioned that you can get some plants to grow on sandy soil. Just that you can’t get the forests, which are supposed to be so essential for a non-clay tech world. ---
**Author:** ![MrDibble](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/mrdibble/32/114_2.png) [@MrDibble](https://boards.straightdope.com/u/MrDibble)\ **Post date:** [December 19, 2015, 2:16pm UTC](https://boards.straightdope.com/t/technology-on-a-planet-with-only-the-25-essential-elements-for-life/740657/48 "2015-12-19T14:16:04Z")
To re-iterate my answer to the OP, in case it wasn’t clear - without Al in your crust, you’re _never_ leaving the stone age. You _might_ make it to _something_ like the Pre-Pottery Neolithic, but you’re not going to be doing any metallurgy other than native metals + meteoric iron and that doesn’t get you to the OP’ “no problem” Steam Age. It doesn’t even get you to the Bronze Age. ---
**Author:** ![the\_diego](https://avatars.discourse-cdn.com/v4/letter/t/7bcc69/32.png) [@the\_diego](https://boards.straightdope.com/u/the_diego)\ **Post date:** [December 20, 2015, 11:40pm UTC](https://boards.straightdope.com/t/technology-on-a-planet-with-only-the-25-essential-elements-for-life/740657/49 "2015-12-20T23:40:05Z")
So this thread’s still alive. The short answer to “man would never \_\_\_ without \_\_\_” is that man is there to begin with. That’s the most important assumption. It means all requirements needed for animals to evolve from fish to man have been met by the 25. I’m guessing you have productive forests, rich grazing areas, navigable rivers full of fish and kept live by acres of broad-leaf forests on either side feeding it nitrates and phosphates and what-have-you. The small nit picks: no-clay forests - look at high energy fluvial areas like old flood plains. The ground is highly winnowed by river action and seasonal floods. There’s practically no clay or non-clay mud. Where the river oxbows away from a spot, forests appear. You also have the rice lands in northern India which are seasonally flooded and silt from the Himalayas are regularly dumped. The soil isn’t clayey. And yet rice is planted and there are forested areas. Also look at the pine barrens. Hardly any clay there. However, I must hasten to say that forests ideally grow in more stable areas, areas with bed rock just below the surface where (in this world) clay is formed through slow physico-chemical action and tree roots have something to anchor to. No ceramics - one doesn’t need pottery technology to smelt metal. In fact, smelted iron or copper even predates ceramics in some parts of the world. Just discount the fact that clay relics are preserved better than wood, or leather, or even metals. The only real use for ceramic is for holding vessels and building material. Lots of possible substitutes available for a resourceful organism if he/it was able to evolve to a level of intelligence. ---
**Author:** ![MrDibble](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/mrdibble/32/114_2.png) [@MrDibble](https://boards.straightdope.com/u/MrDibble)\ **Post date:** [December 21, 2015, 8:17am UTC](https://boards.straightdope.com/t/technology-on-a-planet-with-only-the-25-essential-elements-for-life/740657/50 "2015-12-21T08:17:56Z")
> [@the\_diego](#): > > So this thread’s still alive. The short answer to “man would never \_\_\_ without \_\_\_” is that man is there to begin with. That’s the most important assumption. It means all requirements needed for animals to evolve from fish to man have been met by the 25. The OP didn’t say “man”, it said “intelligent life” > [@](#): > > The small nit picks: no-clay forests - look at high energy fluvial areas like old flood plains. The ground is highly winnowed by river action and seasonal floods. There’s practically no clay or non-clay mud.[…]You also have the rice lands in northern India which are seasonally flooded and silt from the Himalayas are regularly dumped. The soil isn’t clayey.[…] Also look at the pine barrens. Hardly any clay there. We’re not talking about “practically” or “hardly” any clay. 0% clay, 0% any Al-containing minerals at all. > [@](#): > > No ceramics - one doesn’t need pottery technology to smelt metal. One doesn’t _today_. One needs it to develop the idea of iron or copper smelting in the first place, and to construct the earliest furnaces and forges. > [@](#): > > In fact, smelted iron or copper even predates ceramics in some parts of the world Cite for this, frankly, incredible claim? > [@](#): > > The only real use for ceramic is for holding vessels and building material. This is utter nonsense. Just look at metallurgy: What are you making your tuyères out of, if not clay? Your crucibles? And how are you lining your forges? What are you making your glass furnaces out of? How did you even get the idea for artificial glass? You’re not making faience without the example of ceramics first (or clay furnaces to fire it in) > [@](#): > > Lots of possible substitutes available for a resourceful organism if he/it was able to evolve to a level of intelligence. Just intelligence is not enough to reason your way to high tech. You need the low tech first, which can be [built on](http://mygeologypage.ucdavis.edu/cowen/~gel115/115CH3.html). You need to first learn to air-dry pots, then bake them in an open fire, then fire them, before you have the ability to even reach the temperatures that smelt copper and iron. Without that, you’d think lead and tin were the only metals that you _could_ smelt. And even those are going to do you a fat lot of good without something to melt them in - baskets and bladders aren’t going to do so well at smelting over a fire, are they, now? ---
**Author:** ![the\_diego](https://avatars.discourse-cdn.com/v4/letter/t/7bcc69/32.png) [@the\_diego](https://boards.straightdope.com/u/the_diego)\ **Post date:** [December 21, 2015, 9:05am UTC](https://boards.straightdope.com/t/technology-on-a-planet-with-only-the-25-essential-elements-for-life/740657/51 "2015-12-21T09:05:58Z")
“Cite for this, frankly, incredible claim?” I can mention the Kan-kanae mountain tribesmen in northern Philippines. While they may have known ceramic products brought in by the Chinese as early as the 7th century, or from the lowland tribes, there is no evidence that they made their own clay products. But they discovered the Lepanto enargite copper deposit, sometime in the 18th century and exploited the deposit until the Spaniards went into systematic production in 1875. I worked in Lepanto in the late 80s. The mountain tribesmen were also active gold panners at the time. “This is utter nonsense. Just look at metallurgy: What are you making your tuyères out of, if not clay? Your crucibles? And how are you lining your forges?” Collect black iron sand on the beach. Put it in a shallow depression on the ground. Build a fire on it, fan the fire using some kind of blow tube. Heat to at least 1,200 degrees. Roll out the blob of semi-molten iron/steel with a stick. Shape and flatten it with rocks. Let it cool. Sharpen it on a rough stone surface. Go out and kill something, get a section of the femur, jam the tang of the blade in and bind it with sinew from the kill. Voila, a knife. The Vikings made steel using beehive furnaces. Of course they used clay a lot but a stack of stones daubed with sand and non-clay mud, or animal dung, and lined on the inside with ash will also work. Later on, man will discover that SiMatic minerals make great refractory linings. ---
**Author:** ![MrDibble](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/mrdibble/32/114_2.png) [@MrDibble](https://boards.straightdope.com/u/MrDibble)\ **Post date:** [December 21, 2015, 11:49am UTC](https://boards.straightdope.com/t/technology-on-a-planet-with-only-the-25-essential-elements-for-life/740657/52 "2015-12-21T11:49:56Z")
> [@the\_diego](#): > > “Cite for this, frankly, incredible claim?” > > I can mention the Kan-kanae mountain tribesmen in northern Philippines. While they may have known ceramic products brought in by the Chinese as early as the 7th century, or from the lowland tribes, there is no evidence that they made their own clay products. But they discovered the Lepanto enargite copper deposit, sometime in the 18th century and exploited the deposit until the Spaniards went into systematic production in 1875. I worked in Lepanto in the late 80s. The mountain tribesmen were also active gold panners at the time. You realize your say-so is not a cite, right? Where’s the _cite_ for them smelting the copper (which is certainly believable - 1700s is not unbelievable, they were hardly an uncontacted H-G people like some New Guinea highlanders), and the _cite_ for them not having any pottery (which I _highly_ doubt - these are rice terrace farmers, what did they cook their rice in? Their Kalinga neigbours are well-known for their pots (at least, in archaeology circles), why would they not have any?) And anyway, you admit in your own statement that they were not ignorant of ceramics, so how does that “pre-date” anything? > [@](#): > > Collect black iron sand on the beach. Put it in a shallow depression on the ground. Build a fire on it, fan the fire using some kind of blow tube. Yeay, this would be the “tuyère” I mentioned. What are you using for it? Not something organic that’s going to burn up way before you reach smelting temperatures, I hope… More importantly, _why_ would any creature even _think_ of trying this whole process out if they’ve never smelted iron or anything else before? > [@](#): > > Heat to at least 1,200 degrees. Roll out the blob of semi-molten iron/steel with a stick. You’re _never_ getting steel in the mix if you’re using an open fire. > [@](#): > > Shape and flatten it with rocks. How are you going to get the slag out without reheating it? Otherwise you just have an iron-rich lump of rock. Do you even know how the bloomery iron process works? > [@](#): > > Let it cool. Sharpen it on a rough stone surface. Go out and kill something, Why on earth would you go to all that trouble, when a sharp stone gets you that same result? > [@](#): > > The Vikings made steel using beehive furnaces. Of course they used clay a lot but a stack of stones daubed with sand and non-clay mud, or animal dung, and lined on the inside with ash will also work. How is this stuff going to stick to the sides, and remain so, without a clay fraction? Non-clay silts aren’t plastic and sticky. Animal dung (which I’m very familiar with as a building material) can be clay-like, but then it can’t sustain smelting temperatures - it’ll be fuel, not walls. A beehive furnace without clay walls is going to collapse. Even the primitive bowl furnaces of the pre-Roman Britons used clay linings. > [@](#): > > Later on, man will discover that SiMatic minerals make great refractory linings. The non-human intelligent species the OP postulates isn’t going to get the chance to discover that - those sorts of materials only become accessible with industrial-level tech, and they’re never getting there. ---
**Author:** ![the\_diego](https://avatars.discourse-cdn.com/v4/letter/t/7bcc69/32.png) [@the\_diego](https://boards.straightdope.com/u/the_diego)\ **Post date:** [December 22, 2015, 12:11am UTC](https://boards.straightdope.com/t/technology-on-a-planet-with-only-the-25-essential-elements-for-life/740657/53 "2015-12-22T00:11:27Z")
You need 1,400 degrees to make steel. Yes, almost impossible in a wood furnace. But there’s a “but” in everything, which you either don’t know or don’t bother with. That’s why these exchanges can get tedious. 1,400 degrees is an average temperature needed to produce MOLTEN steel. Even Japanese tataras for making sword steel don’t reach that. Wood furnaces can reach 1,200 with a good blower system. This is enough to produce steel and carbides somewhere within your mass of iron oxide. You don’t produce a melt. Just a lump of varying composition from un-smelted magnetite, to ferrite, to steel and iron carbides. Japanese smiths would break that lump and test each piece individually for carbon content. In my blob example, just forge the whole thing. You’re not out to join a cutting competition. There was an experiment wherein four (human) couples were made to live off the land with nothing but the rough clothes they were wearing (wore out in six months) and some livestock. The first three months was rough going, even though they can already produce a fire. Their lifestyle changed drastically when one of them was able to fashion a crude knife using the method I described. “Why would anyone bother to do this if they’ve never smelted iron or anything before.” This is already in the realm of psychology; what drives an intelligent being to do something out of the ordinary, seemingly without any practical end. This is clearly your homework, not mine. The question also applies as to why basic heat treating and carburization were discovered when you already had usable steel before that. And later, why someone bothered to invent the Bessemer process, all the way to powder sintering. ---
**Author:** ![dracoi](https://avatars.discourse-cdn.com/v4/letter/d/90db22/32.png) [@dracoi](https://boards.straightdope.com/u/dracoi)\ **Post date:** [December 22, 2015, 1:26am UTC](https://boards.straightdope.com/t/technology-on-a-planet-with-only-the-25-essential-elements-for-life/740657/54 "2015-12-22T01:26:11Z")
> [@MrDibble](#): > > Then you’re into absolute speculation that’s outside the scope of the OP’s question as posed, IMO. Anything is possible, I guess - 25-element world could evolve biological computers and naturally-occuring carbon-fibre space elevators, if you like. Is it really such a stretch, though? How about this: stands of alt-Earth trees support each other in a way that Earth trees do not. When branches and roots touch those of another tree, they wrap around each other… a forest on alt-Earth stands up because a billion tons of trees are mutually “holding hands.” Maybe they are floating on sand, but nothing can knock them all over at once. This is not a carbon fiber space elevator - it’s something that modern plants can do _right now_ if you tweak their growth behavior correctly. And let’s be honest, if you lived on a world without cellulose and I described it to you, would you believe me? Strong as steel. Indigestible to just about everything. Lasts hundreds of years. And made entirely from sugar! But there it is. As a plant material, it’s so superior to other options that there aren’t other options. ---
**Author:** ![MrDibble](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/mrdibble/32/114_2.png) [@MrDibble](https://boards.straightdope.com/u/MrDibble)\ **Post date:** [December 22, 2015, 7:15am UTC](https://boards.straightdope.com/t/technology-on-a-planet-with-only-the-25-essential-elements-for-life/740657/55 "2015-12-22T07:15:07Z")
> [@the\_diego](#): > > You need 1,400 degrees to make steel. Yes, almost impossible in a wood furnace. Naah - you need the temperature AND a reducing carbon-rich atmosphere, or all you’re getting is iron oxides. And \*that’s \*what you won’t get from an open wood fire. > [@](#): > > There was an experiment wherein four (human) couples were made to live off the land with nothing but the rough clothes they were wearing (wore out in six months) and some livestock. The first three months was rough going, even though they can already produce a fire. Their lifestyle changed drastically when one of them was able to fashion a crude knife using the method I described. Were these 4 people raised completely ignorant of iron and the way it’s made? Otherwise, i don’t see the relevance. I’m not questioning that it’s possible to achieve a crude knife this way, I could do it myself (given clay :)). That’s not the point. > [@](#): > > “Why would anyone bother to do this if they’ve never smelted iron or anything before.” This is already in the realm of psychology; what drives an intelligent being to do something out of the ordinary, seemingly without any practical end. This is clearly your homework, not mine. The fuck it is. You’re the one proposing a stone-age person is just going to up and invent bloomery iron-smelting spontaneously. I’m the one saying that’s a bigger fantasy than the entire _oeuvre_ of Tolkien, Martin, Eddings and Penthouse letters, combined . _You_ defend it, it’s _your_ thesis, not mine. > [@](#): > > The question also applies as to why basic heat treating and carburization were discovered when you already had usable steel before that. They’re a side-effect of the processes used to shape and smelt. They weren’t invented out of whole cloth, they way you imagine iron smelting was. Are you unaware of the idea of serendipity in technological progress? > [@](#): > > And later, why someone bothered to invent the Bessemer process, all the way to powder sintering. By that time, we’re into directed experiment, coupled with a fairly advanced understanding of chemistry and metallurgy. Are you seriously suggesting your primitive being will have that foundation without the [technological](https://en.wikipedia.org/wiki/Industrial_Revolution) and [social](https://en.wikipedia.org/wiki/Age_of_Enlightenment) backing that led to something like Bessemer? ---
**Author:** ![MrDibble](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/mrdibble/32/114_2.png) [@MrDibble](https://boards.straightdope.com/u/MrDibble)\ **Post date:** [December 22, 2015, 7:20am UTC](https://boards.straightdope.com/t/technology-on-a-planet-with-only-the-25-essential-elements-for-life/740657/56 "2015-12-22T07:20:52Z")
> [@dracoi](#): > > Is it really such a stretch, though? No, but like I said, it’s taking things in an IMHO direction not a GQ one. A space I’m happy to play in, BTW - I _love_ specbio - Barlowe, Snaiad, all that jazz. > [@](#): > > And let’s be honest, if you lived on a world without cellulose and I described it to you, would you believe me? Depends - do we have lignin, chitin, keratin and silk on this cellulose-free world? Because those sorts of properties in organic polymers aren’t _that_ surprising. ---
**Author:** ![the\_diego](https://avatars.discourse-cdn.com/v4/letter/t/7bcc69/32.png) [@the\_diego](https://boards.straightdope.com/u/the_diego)\ **Post date:** [December 22, 2015, 8:22am UTC](https://boards.straightdope.com/t/technology-on-a-planet-with-only-the-25-essential-elements-for-life/740657/57 "2015-12-22T08:22:24Z")
> [@MrDibble](#): > > Naah - you need the temperature AND a reducing carbon-rich atmosphere, or all you’re getting is iron oxides. And \*that’s \*what you won’t get from an open wood fire. This could be confusing to some. A reduction reaction for iron oxide simply entails heating it enough to allow the oxygen to react with carbon introduced. The reaction will happen readily, since carbon is much more reactive than iron. It’s not about increasing or decreasing the amount of oxygen in a fire. :smack: There’s nothing wrong with an open wood fire for generating a reduction reaction. ---
**Author:** ![MrDibble](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/mrdibble/32/114_2.png) [@MrDibble](https://boards.straightdope.com/u/MrDibble)\ **Post date:** [December 22, 2015, 5:01pm UTC](https://boards.straightdope.com/t/technology-on-a-planet-with-only-the-25-essential-elements-for-life/740657/58 "2015-12-22T17:01:59Z")
> [@the\_diego](#): > > This could be confusing to some. A reduction reaction for iron oxide simply entails heating it enough to allow the oxygen to react with carbon introduced. The reaction will happen readily, since carbon is much more reactive than iron. It’s not about increasing or decreasing the amount of oxygen in a fire. No, it’s not about that, it’s about the amount of _free carbon_. That’s why Industrial steelmaking used coke, not coal, and Iron Age crucible steel used charcoal, not wood. I don’t know of any Iron Age smelting that used wood, not charcoal. I’d _love_ a cite to the contrary. If you have any cites, that is. ---
**Author:** ![dracoi](https://avatars.discourse-cdn.com/v4/letter/d/90db22/32.png) [@dracoi](https://boards.straightdope.com/u/dracoi)\ **Post date:** [December 22, 2015, 5:38pm UTC](https://boards.straightdope.com/t/technology-on-a-planet-with-only-the-25-essential-elements-for-life/740657/59 "2015-12-22T17:38:25Z")
> [@MrDibble](#): > > No, but like I said, it’s taking things in an IMHO direction not a GQ one. A space I’m happy to play in, BTW - I _love_ specbio - Barlowe, Snaiad, all that jazz. I’m just going from the OP’s original conditions: “Lets say by bad luck that a planet had only these 25 elements and none of the others were present at all anywhere in the planets crust / surface. Intelligent life evolves…” So my understanding is that we were always talking about organisms that evolved to survive in this alternate element-poor scenario. ---
**Author:** ![MrDibble](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/mrdibble/32/114_2.png) [@MrDibble](https://boards.straightdope.com/u/MrDibble)\ **Post date:** [December 24, 2015, 3:46pm UTC](https://boards.straightdope.com/t/technology-on-a-planet-with-only-the-25-essential-elements-for-life/740657/60 "2015-12-24T15:46:26Z")
> [@dracoi](#): > > I’m just going from the OP’s original conditions: “Lets say by bad luck that a planet had only these 25 elements and none of the others were present at all anywhere in the planets crust / surface. Intelligent life evolves…” > > So my understanding is that we were always talking about organisms that evolved to survive in this alternate element-poor scenario. Fair enough. [Previous page](https://boards.straightdope.com/t/technology-on-a-planet-with-only-the-25-essential-elements-for-life/740657.md?page=2)