5 ms·
The guide keeps saying it's because they disipate heat so quickly, but I thought it was supposed be quite the opposite?
by hanoz 7y ago
The guide keeps saying it's because they disipate heat so quickly, but I thought it was supposed be quite the opposite?
- jansan 7y agoAnd also, dissipate to where? To the hotter parts of the material? To the air? I think he is wrong.
- balfirevic 7y agoThe outermost part dissipates heat quickly to the air which lowers it's temperature (the temperature of the outermost part, that is). In regular materials, the heat flows quickly from the center, so the temperature of the outer layer cannot drop significantly in such a short amount of time. But this material conducts heat so poorly that this doesn't happen, so the outer layer stays cool.
- jtbayly 7y agoFascinating. So it’s both: it conducts to air quickly, but to itself slowly.
- kragen 7y agoAt these temperatures, radiation is usually a much more significant heat transport mechanism than conduction or convection, so probably a substantial amount of that heat was deposited in the walls of the room and the bystanders.
- javagram 7y agoYes, i think the guide is saying it backwards. The caption of the video says “ Space Shuttle thermal tiles conduct heat so poorly that after being in a 2200 °F oven for hours, you can pick them up with your bare hands only seconds after they come out, still glowing hot” This makes sense - the tiles themselves are at 2200 degrees but are not transmitting the heat quickly to you while you touch them for a brief period of time.
- JorgeGT 7y agoCorrect. Similarly, even though space is terribly cold, you could be exposed to it briefly without getting cold. Low pressure however is the real danger...
- stanmancan 7y agoWhich is also why cooling things down in space is a unique challenge. There’s nothing to carry the heat away from whatever it is you’re trying to cool.
- dredmorbius 7y agoWell, nothing (vacuum) will carry away heat, as radiated blackbody radiation. Slowly. https://en.wikipedia.org/wiki/Thermal_radiation https://en.wikipedia.org/wiki/Thermal_radiation
- rrauenza 7y agoAnd a large aspect of the game Oxygen Not Included! Makes it even harder they don't model radiative heating..
- dreamcompiler 7y agoYes. Same idea as when you stick your hand into a 400F oven to pull the pizza out. Doesn't hurt because air is a poor heat conductor. But if you touch the 400F metal pan, it will hurt.
- jlawson 7y agoThe tiles are extremely low-density, so their heat dissipates quickly because they don't hold much of it. So the corners of the tiles become cool within a few seconds, even though the material inside just a centimeter away is at thousands of degrees. That's why he said to touch the corners. And why you can see the corners not glowing, while the center of the sides keeps glowing.
- 4gotunameagain 7y agoYou're right, these are pure silica tiles, very low density and very low heat conductivity. https://en.wikipedia.org/wiki/LI-900 https://en.wikipedia.org/wiki/LI-900
- deleted 7y ago[deleted]
- starpilot 7y agoYes, they are insulators, so they reduce heat transfer.
- refurb 7y agoPlus the have a very low heat capacity. So although they might be 2200F, they hold very little heat. Similar to being in a sauna. A human can stand inside a 150F sauna without getting burned (the air doesn't hold much heat and slowly transfers it to your body). But if had 150F water against your skin, you'd be burned quite quickly.