An Iron Golem is heavier than a human, but could at the very least run across a lake of lava, in a manner similar to certain lizards and insects.
Small animals running across liquids is because of surface tension, not viscosity; it could likely make its way across lava for a bit, but getting stuck would be a serious risk.
And Iron Golems are bipedal, which means that at any given step, they have their entire mass bearing down on a single iron foot. If the golem were to deliberately lay prone and attempt to paddle across, there would be different mechanics in play
People keep saying it sinks. This is wrong. Let me make it clear.
solid/Liquid/gas
Heavier things sink instantly though gas. You put oxygen on top of helium and the oxygen goes down and the hydrogen up. Similarly, stones, water, etc. drop though nitrogen gas. But if you make something like an aerogel it could float above tungsten hexafluroide.
Heavier things CRUSH solids. They do not sink though them, they crush them, but remain on top.
With liquids, it does NOT just depend on weight, but you need to know the VISCOSITY. That is, it's resistance to deformation. Room temperature Water has a viscosity of about 1 mPas Room temperature ketchup has a viscosity of about 5k-2k mPas (or 5 x 10^3 to 2 x 10^4).
Lava has a viscosity of about 100,000 or 10^6, which is similar to cold, thick, peanut butter. You can walk on both fairly easily, as long as you do not stop moving (and survive the temperature). If you fall asleep on it, you would drown in your sleep.
An Iron Golem is heavier than a human, but could at the very least run across a lake of lava, in a manner similar to certain lizards and insects.
No such thing given that we don't have any real life example to pull from regarding Iron Golems and lava. Therefore, seeing that's its an imaginary scenario using an imaginary creature, it's left to the imagination of those creating it to determine what happens. Therefore, how could there be a right, wrong, better, or best?
I appreciate the breakdown and math but don't start any "how to D&D" response with absolutes.
Whilst I agree that arguing the exact physics behind D&D isn't the best idea, I do have to argue against the idea of an Iron Golem walking on liquid lava.
Assuming Mog_Dracov's numbers are right and the lava is as thick as thick peanut butter, what do you think happens if you take a tank full of thick peanut butter and place an anvil on top of it? what happens if you stack another 20 or so anvils on top of that? It's always going to sink.
Further to that, there's no exact viscosity for lava - I distinctly remember being taught of a greta variety of different types of volcano, and some flow very quickly with much hotter, less viscous lava. For a pool to exist to hold the gole, it would be deep, which would likely mean it's going to be much hotter than lava flowing in thin sheets over a surface (which is likely where the viscosity measurement came from, because it's where it's relevant to how fast it flows).
Whilst I agree that arguing the exact physics behind D&D isn't the best idea, I do have to argue against the idea of an Iron Golem walking on liquid lava.
Assuming Mog_Dracov's numbers are right and the lava is as thick as thick peanut butter, what do you think happens if you take a tank full of thick peanut butter and place an anvil on top of it? what happens if you stack another 20 or so anvils on top of that? It's always going to sink.
Further to that, there's no exact viscosity for lava - I distinctly remember being taught of a greta variety of different types of volcano, and some flow very quickly with much hotter, less viscous lava. For a pool to exist to hold the gole, it would be deep, which would likely mean it's going to be much hotter than lava flowing in thin sheets over a surface (which is likely where the viscosity measurement came from, because it's where it's relevant to how fast it flows).
As pointed out earlier in this thread, it's challenging to make definite conclusions about the iron golem's density, as we don't know if it's hollow, like Alphonse Elric. If your GM rules it's hollow, it likely has neutral bouyancy in lava, so it has no reason to sink. If it's iron throughout, I think we worked out it's about 2.5x as dense as the lava, or reasonably close to dropping an aluminum golem onto cold milk (clearly a common occurrence, farms are dangerous places, ok?), at which point questions like viscosity and displacement come up.
It's fine to assume a lava, like we did with density - no one's expecting the GM to stat out the specific lava in question based on local geology. Apparently, lava viscosity is primarily determined by how much silica is in it (and, of course, absolutely does also depend on temperature), but all lava is incredibly viscous compared to water. Intermediate lava, the second most viscous kind, is slightly more viscous than smooth peanut butter at 1200C, but felsic lava, the most viscous kind (this is the one that often contains obsidian) is 100 times as viscous at the same temperature. However, felsic magma is also less dense than what we assumed earlier. In fact, from what I can tell, magma density and viscosity inversely correlate - denser magma is less viscous, and less dense magma is more viscous. Here are some lava numbers - all values assume 1200C:
Magma Type Density (kg/m^3) Viscosity (cP) Basalt 2650–2800 10^4-10^5 (approximately mustard) Andesite 2450–2500 3.5*10^6 (slightly more than peanut butter) Rhyolite 2180–2250 10^8 (particularly thick caulk)
That density we worked with earlier in this thread is sus - I can't figure out what kind of lava allegedly has that density. These values are closer to 1/3 the density of iron. But if we assume a Rhyolite lava for simplicity, the golem will almost certainly sink, but it'll sink very, very slowly.
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And Iron Golems are bipedal, which means that at any given step, they have their entire mass bearing down on a single iron foot. If the golem were to deliberately lay prone and attempt to paddle across, there would be different mechanics in play
No such thing given that we don't have any real life example to pull from regarding Iron Golems and lava. Therefore, seeing that's its an imaginary scenario using an imaginary creature, it's left to the imagination of those creating it to determine what happens. Therefore, how could there be a right, wrong, better, or best?
I appreciate the breakdown and math but don't start any "how to D&D" response with absolutes.
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Whilst I agree that arguing the exact physics behind D&D isn't the best idea, I do have to argue against the idea of an Iron Golem walking on liquid lava.
Assuming Mog_Dracov's numbers are right and the lava is as thick as thick peanut butter, what do you think happens if you take a tank full of thick peanut butter and place an anvil on top of it? what happens if you stack another 20 or so anvils on top of that? It's always going to sink.
Further to that, there's no exact viscosity for lava - I distinctly remember being taught of a greta variety of different types of volcano, and some flow very quickly with much hotter, less viscous lava. For a pool to exist to hold the gole, it would be deep, which would likely mean it's going to be much hotter than lava flowing in thin sheets over a surface (which is likely where the viscosity measurement came from, because it's where it's relevant to how fast it flows).
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As pointed out earlier in this thread, it's challenging to make definite conclusions about the iron golem's density, as we don't know if it's hollow, like Alphonse Elric. If your GM rules it's hollow, it likely has neutral bouyancy in lava, so it has no reason to sink. If it's iron throughout, I think we worked out it's about 2.5x as dense as the lava, or reasonably close to dropping an aluminum golem onto cold milk (clearly a common occurrence, farms are dangerous places, ok?), at which point questions like viscosity and displacement come up.
It's fine to assume a lava, like we did with density - no one's expecting the GM to stat out the specific lava in question based on local geology. Apparently, lava viscosity is primarily determined by how much silica is in it (and, of course, absolutely does also depend on temperature), but all lava is incredibly viscous compared to water. Intermediate lava, the second most viscous kind, is slightly more viscous than smooth peanut butter at 1200C, but felsic lava, the most viscous kind (this is the one that often contains obsidian) is 100 times as viscous at the same temperature. However, felsic magma is also less dense than what we assumed earlier. In fact, from what I can tell, magma density and viscosity inversely correlate - denser magma is less viscous, and less dense magma is more viscous. Here are some lava numbers - all values assume 1200C:
Magma Type Density (kg/m^3) Viscosity (cP)
Basalt 2650–2800 10^4-10^5 (approximately mustard)
Andesite 2450–2500 3.5*10^6 (slightly more than peanut butter)
Rhyolite 2180–2250 10^8 (particularly thick caulk)
That density we worked with earlier in this thread is sus - I can't figure out what kind of lava allegedly has that density. These values are closer to 1/3 the density of iron. But if we assume a Rhyolite lava for simplicity, the golem will almost certainly sink, but it'll sink very, very slowly.