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Iridium will always be the densest element in my heart.
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Apr 7, 2016 02:58
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I was marking geophysics exams where the solution to a particular problem of "What is making the gravity high here?" was described to us as being a 10-meter sphere of 9-9s pure iridium, buried ten meters under the surface. Everyone then did the maths on modeling up the exact parameters of the sphere and dutifully demonstrating their work on how that solution would have been arrived at. Extra credit was awarded to the students who then went on to say "but that's probably more iridium than is in the entire crust of the Earth and definitely more iridium than has ever been mined". One whole section of my thesis was on iridium, it's my most favourite element. I have a little sample of it on my desk that's about ten grams, in a display case. It's cool to look at it and go "you were definitely formed in a supernova".
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Apr 7, 2016 03:08
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Isn't Iridium so rare because there was basically none of it in the initial formation of the planet? I know Technetium basically doesn't exist on Earth because it's stupid radioactive and all natural deposits have since all decayed into its products, but Iridium isn't particularly radioactive.
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Apr 7, 2016 03:25
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Kwyndig posted:Isn't Iridium so rare because there was basically none of it in the initial formation of the planet? I know Technetium basically doesn't exist on Earth because it's stupid radioactive and all natural deposits have since all decayed into its products, but Iridium isn't particularly radioactive. There was a lot of it to go around when the Earth formed (essentially at the same concentration you find in meteorites), it's just that because it doesn't really interact with anything, all of it sunk into the core while the Earth was still molten. A little bit of the more common precious metals were able to hang around near the surface because they complexed with sulfur and got belched back upwards by volcanic explosions before they could sink too deep.
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Apr 7, 2016 03:49
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Kwyndig posted:Isn't Iridium so rare because there was basically none of it in the initial formation of the planet? I know Technetium basically doesn't exist on Earth because it's stupid radioactive and all natural deposits have since all decayed into its products, but Iridium isn't particularly radioactive. There's a popular theory that most or all of the precious metals in the crust of the Earth come from the Late Heavy Bombardment, where we were hammered by a significant number of meteorites, all of which had the potential to be iron-nickel ± PGE-Au-Ag in composition. At that time (somewhere between 4.1 and 3.8Ga (billion years ago)) the Earth had already cooled to the point where it had a solid crust (that was then smashed to bits by the bombardment); the exact make up of the mantle and core would have been different due to the higher relict heat but basically the same. So while basically all of the precious metals that were part of the accretion of the planet had already sunk to the core, this next lot were able to stick around on the surface and form metals. I personally like the theory from my reading but there's enough arguments against it that it might not have happened and the explanation for these elements in the crust needs to go back to the drawing board. It's really bloody hard to figure out definitively what happened around four billion years ago without a fair bit of "it is interpreted that" and "these observations suggest that". Venusian Weasel posted:There was a lot of it to go around when the Earth formed (essentially at the same concentration you find in meteorites), it's just that because it doesn't really interact with anything, all of it sunk into the core while the Earth was still molten. Yes and no on the lack of interaction. High-density transition metals such as platinum group elements are siderophiles, which means they readily dissolve in molten iron and form metallic bonds, essentially alloying themselves with iron and nickel. I mean, I know you know this, this is really just for the folks following along at home. Density isn't the best explanation of elemental differentiation into the crust or mantle/core; mercury is twice as dense as iron but because it so readily complexes to form sulphides, selenides and tellurides it stuck around in the crust.
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Apr 7, 2016 04:25
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Memento posted:One whole section of my thesis was on iridium, it's my most favourite element. I have a little sample of it on my desk that's about ten grams, in a display case. It's cool to look at it and go "you were definitely formed in a supernova". One of my cow orkers has this block of tungsten alloy on his desk, it's about a 3" cube and it has "17.9 g/cc" written on it. Your brain isn't evolutionarily equipped to deal with it. You pick it up and it just plain has more inertia than your senses are telling you anything that size should have. It's like when you're driving a car and get up to over about 110mph, the reptilian part of your brain just says "Okay, I'm out, this is all on you now."
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Apr 7, 2016 04:38
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So, aside from the lichens that hang out in the Chernobyl reactor, does anyone know off hand about some extreme examples of things that survive and thrive in environments that are highly radioactive/metallically poisonous? I'm utterly fascinated by fungus and just how unbelievably resilient and adaptable it is. Today, one of my friends who's a Chem major told me about how their professor had a microscope up in front of their class, focused on fungal yeasts that were living in mine tailing from a badly done gold mine from the early 1800s. The water is unnaturally blue from the amount of copper in it, and yet this fungus is just hanging out, happily nomming on sulfides.
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Apr 7, 2016 04:47
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GWBBQ posted:Water burns in a fluorine-rich environment Yeah but I can't really do that in my back yard, and something tells me getting the guys down at UW to light some faygo on fire for shiggles would be hard.
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Apr 7, 2016 04:52
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A White Guy posted:So, aside from the lichens that hang out in the Chernobyl reactor, does anyone know off hand about some extreme examples of things that survive and thrive in environments that are highly radioactive/metallically poisonous? I'm utterly fascinated by fungus and just how unbelievably resilient and adaptable it is. Today, one of my friends who's a Chem major told me about how their professor had a microscope up in front of their class, focused on fungal yeasts that were living in mine tailing from a badly done gold mine from the early 1800s. The water is unnaturally blue from the amount of copper in it, and yet this fungus is just hanging out, happily nomming on sulfides. Living things need energy to keep living; the corollary to this is that if there is energy somewhere, something will take advantage of it. The term for something that lives somewhere you would expect life to be blasted into its component molecules is extremophile. Hydrothermal vents at the bottom of the ocean - commonly referred to as either black or white smokers - provide heat and sulphur or methane that can be used for energy. There's also a species of bacteria that has evolved to use the very faint light given off by some of these vents for photosynthesis, which is super neat. So we're talking about water that could have a pH of under 2, is 100-150°C and under 250+ atmospheres of pressure. Life will, indeed, find a way. Some reading to kick you off: https://en.wikipedia.org/wiki/Extremophile https://en.wikipedia.org/wiki/Hydrothermal_vent#Biological_communities Also, "a badly done gold mine from the early 1800s" unfortunately doesn't really narrow down the field.
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Apr 7, 2016 04:57
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Memento posted:"you were definitely formed in a supernova". I do this in the mirror while flexing every morning.
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Apr 7, 2016 05:06
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Keiya posted:Yeah but I can't really do that in my back yard, and something tells me getting the guys down at UW to light some faygo on fire for shiggles would be hard. Well what kind of chemists do they think they are, not being willing to light things on fire with fluorine just to see if they'll burn?
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Apr 7, 2016 05:07
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Kalman posted:Well what kind of chemists do they think they are, not being willing to light things on fire with fluorine just to see if they'll burn? It's not like there's much mystery involved with that. The list of things that don't burn with fluorine is relatively small. Most of them are things that have already been 'burned' in fluorine. What you want is a pyromaniac with access to lots of fluorine and some good video cameras.
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Apr 7, 2016 05:21
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jetz0r posted:It's not like there's much mystery involved with that. The list of things that don't burn with fluorine is relatively small. Most of them are things that have already been 'burned' in fluorine. Somebody's going to get a whole lot of views for their YouTube video titled "Let's see what happens when you drop a bottle of Faygo into a vat of liquid fluorine!"
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Apr 7, 2016 05:30
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Burning things in fluorine also means you have gaseous fluorine around. Most sane people would say gently caress that.
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Apr 7, 2016 05:34
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Phanatic posted:One of my cow orkers has this block of tungsten alloy on his desk, it's about a 3" cube and it has "17.9 g/cc" written on it. I'd like to have a 120mm APFSDS-T projectile. They turn up occasionally on the oddball online milsurp stores.  Not sure what I'd do with it other than accidentally trip over it and impale myself (this is the sort of thing that should be displayed horizontal, on a low shelf, behind thick glass), but it'd be a cool curio. 24mmx543mm, mass 4kg (or a hair under an inch diameter, 21-3/8" long, 8lb13oz for us stupid Americans.) How much would a hunk of steel the same size weigh? I'm bad at math. jetz0r posted:It's not like there's much mystery involved with that. The list of things that don't burn with fluorine is relatively small. Most of them are things that have already been 'burned' in fluorine. https://www.youtube.com/watch?v=ep_mf6ZE9U0 Note that Dan's lab coat is basically bloodstained rags.
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Apr 7, 2016 05:34
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Bad Angus! Bad!
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DemeaninDemon posted:Burning things in fluorine also means you have gaseous fluorine around. Most sane people would say gently caress that. All sane people would say gently caress that. It's kind of a prerequisite. Luckily not all people are sane.
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Apr 7, 2016 05:45
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Delivery McGee posted:Not sure what I'd do with it other than accidentally trip over it and impale myself (this is the sort of thing that should be displayed horizontal, on a low shelf, behind thick glass), but it'd be a cool curio. 24mmx543mm, mass 4kg (or a hair under an inch diameter, 21-3/8" long, 8lb13oz for us stupid Americans.) How much would a hunk of steel the same size weigh? I'm bad at math. Wolfram Alpha owns for this stuff. It's 1.931kg, assuming that 24mm is the diameter.
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Apr 7, 2016 05:45
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Delivery McGee posted:Not sure what I'd do with it other than accidentally trip over it and impale myself (this is the sort of thing that should be displayed horizontal, on a low shelf, behind thick glass), but it'd be a cool curio. 24mmx543mm, mass 4kg (or a hair under an inch diameter, 21-3/8" long, 8lb13oz for us stupid Americans.) How much would a hunk of steel the same size weigh? I'm bad at math. Or, assuming it’s pure uranium (I think it’s 90%, so close enough) so you don’t have to assume the geometry, 1.65 kg.
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Apr 7, 2016 05:55
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A White Guy posted:So, aside from the lichens that hang out in the Chernobyl reactor, does anyone know off hand about some extreme examples of things that survive and thrive in environments that are highly radioactive/metallically poisonous? I'm utterly fascinated by fungus and just how unbelievably resilient and adaptable it is. Today, one of my friends who's a Chem major told me about how their professor had a microscope up in front of their class, focused on fungal yeasts that were living in mine tailing from a badly done gold mine from the early 1800s. The water is unnaturally blue from the amount of copper in it, and yet this fungus is just hanging out, happily nomming on sulfides.
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Apr 7, 2016 05:59
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Phanatic posted:One of my cow orkers has this block of tungsten alloy on his desk, it's about a 3" cube and it has "17.9 g/cc" written on it. I bought a 2.4 kg hunk of tungsten for my own desk, and I’m honestly kind of disappointed. It doesn’t have much of that effect on me or, it seems, on other people who have picked it up. I don’t know why. Possibly it’s not a sufficiently compact shape or it’s just big enough (and obviously made of metal) that your brain expects it to be “heavy” and doesn’t care that it’s more than twice as heavy as an iron bar of the same size would be. Specifically, it’s this shape, $75 from eBay:  From the DoD number, it looks like it’s a ruddervator counterweight for a KC‐135. Platystemon has a new favorite as of 06:24 on Apr 7, 2016 |
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Apr 7, 2016 06:13
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Platystemon posted:I bought a 2.4 kg hunk of tungsten for my own desk, and I’m honestly kind of disappointed. It doesn’t have much of that effect on me or, it seems, on other people who have picked it up. From what I recall, the poisoning effects of tungsten are only apparent if you drink wine out of the barrel of your French-army issued assault rifle darthbob88 posted:Deinococcus radiodurans. Discovered in '56 when it proved that hard radiation isn't enough to sterilize a can of meat. Hardy little sunzabitches. Also, probably not the mine you're thinking of, but I must mention the Berkeley Pit. A lake so toxic a flock of geese died after landing on it, but there's still bacteria and fungi, happily digesting the metals and spitting out what might be the next cancer drug. Part of it. There are a lot of areas that were mined with the sole goal of getting gold out of them there hills during the Gold Rush in California, and consequently, we're still dealing with the environmental effects of mine tailings 150 years after. Also, goddamn, life will uh, find a way.
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Apr 7, 2016 06:35
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Platystemon posted:Cadmium is amazing as an industrial plating. It's also amazing for paint pigments, similar to a lot of other heavy metals. A couple of the Vallejo acrylic paints I use have metals such as cadmium in them, and they are extremely vivid. The labels also include a warning saying "Contains cadmium. Not for airbrush use. DO NOT SPRAY THIS PAINT", and I assume it would be a stupid idea to lick the brush, too. E: I'd love to have a set of a tungsten cube and an aluminum cube of identical size, but $160 is a bit much to pay for such a set. KozmoNaut has a new favorite as of 14:01 on Apr 7, 2016 |
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Apr 7, 2016 13:48
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KozmoNaut posted:It's also amazing for paint pigments, similar to a lot of other heavy metals. ..... oh boy. Vallejo paints you say? well. Guess i gots me some cadmium. 
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Apr 7, 2016 14:06
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SneakyFrog posted:..... oh boy. It seems they gradually changed their formulation a couple of years back, to remove all heavy metals. Mine are probably 5 years old, but they may have been sitting in the store for a while before I bought them.
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Apr 7, 2016 15:18
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KozmoNaut posted:It seems they gradually changed their formulation a couple of years back, to remove all heavy metals. Mine are probably 5 years old, but they may have been sitting in the store for a while before I bought them. mine were old overstock. got them eh.. 7-10 years ago?
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Apr 7, 2016 15:20
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It's like how pewter used to contain lead in it. It was easier to do it that way than a safe way and until relatively recently nobody cared if your paint or tiny metal people were toxic if you were stupid enough to put them in your mouth.
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Apr 7, 2016 15:24
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Phanatic posted:It is actually seeing use for that, because with the right recovery equipment it's not prohibitively expensive anymore. And it's such a potent anaesthetic that you can give plenty of oxygen along with it, which makes everyone happy. If it weren't for the expense it would be damned near perfect at that task. Xenon was recently banned by WADA because of its use as a doping agent. This probably fits itt http://www.bbc.co.uk/earth/story/20150904-the-bizarre-beasts-living-in-romanias-poison-cave
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Apr 7, 2016 16:13
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Deteriorata posted:Most of the color of a meteor trail is due to the emission spectra of nitrogen and oxygen that were ionized as it went by. That was my first thought, and after I saw that nickel had a white flame was my third thought too, but I'd still love to see a comprehensive documentation, preferably with spectra. I don't think that's why they use nichrome wire, though, since iron seems to have nice colorful flames at least in some ionization states. I'd imagine it's more the stuff being resistant to corrosion and melting, while being widely available, more than the color of the flames it would produce if ground up. GWBBQ posted:If people encourage me I'll probably be convinced to prove this by grabbing one of the iron-nickel meteorites from my office and bringing it to the chemistry lab. NO DONT I'm sure you can get cheaper nickel somewhere else. 
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Apr 7, 2016 17:59
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This is in response to the poster asking about ways microbes deal with environmental contaminants like heavy metals a bit ago, but I finally found this paper I cited a few years ago about a strain of B. sphaericus that uses heavy metals to literally make armor for itself http://www.ncbi.nlm.nih.gov/pubmed/16005595 Of course it was found in uranium mine tailings which makes it even more
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Apr 7, 2016 19:06
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Moist von Lipwig posted:bitter boobswill namechange tia
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Apr 7, 2016 22:24
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So, in the interests of science, safety and boredom, we were checking out info on the newest automotive refrigerant (r1234ya also known as tetraflouropropene) at work today to see why the stuff is going to be $100 a pound. In the process we decided to check out the msds info on it and were surprised to see it had fun words like "flammable gas 1", "highly flammable" and "thermal decomposition can release hydrogen floride". On the other hand, all of our training material lists it as safe, only mildly flammable compared to the other alternative that was considered (r152, also known as canned air). Any of you guys better at understanding these msds thingies wanna weigh in with an opinion? The cost means I'm not gonna get to play around with it in entirely inappropriate ways any time soon to see just how flammable it is. Not that I really want to after reading the part about creating hydrogen floride when it breaks down due to heat. Edit: I'm guessing that the reason for the difference is the fact that upper and lower flammability levels are fairly close together, meaning there is a narrow range where it will burn. This makes it overall safe to handle under normal conditions, but in that range it would be interesting to deal with. Elmnt80 has a new favorite as of 08:43 on Apr 10, 2016 |
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Apr 10, 2016 08:29
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I cannot answer your specific question, but I would like to point out there's a general chemistry thread in SAL where all the really knowledgeable people hang out: http://forums.somethingawful.com/showthread.php?threadid=3283822 It's possibly a better place for questions like that.
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Apr 10, 2016 08:57
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Elmnt80 posted:So, in the interests of science, safety and boredom, we were checking out info on the newest automotive refrigerant (r1234ya also known as tetraflouropropene) at work today to see why the stuff is going to be $100 a pound. In the process we decided to check out the msds info on it and were surprised to see it had fun words like "flammable gas 1", "highly flammable" and "thermal decomposition can release hydrogen floride". If you crash your car and wind up stuck in a burning wreck you might get to deal with HF gas  Great choice of chemical there.
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Apr 10, 2016 10:33
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Elmnt80 posted:So, in the interests of science, safety and boredom, we were checking out info on the newest automotive refrigerant (r1234ya also known as tetraflouropropene) at work today to see why the stuff is going to be $100 a pound. In the process we decided to check out the msds info on it and were surprised to see it had fun words like "flammable gas 1", "highly flammable" and "thermal decomposition can release hydrogen floride". If your car is in a conflagration with R134a you aren't exactly out of the woods from exotic combustion products. If hot enough it too will form HF and the fluorine analog of phosgene. Fluorine is everywhere in this era of plastic and bespoke gases meant to have specific physical properties. A little different from being flammable, but also the major issue with flammable is the hot gases. You only need to worry about the inherent chemical properties of the gases if you survive the hot part. Mechanics are probably the ones that take the biggest amount of risk in a world with 134a replaced with 1234yf, since they need to store it at quantity in the shop and are the ones controlling the actual movement of it from place to place, which is the most likely step where it wants to be free. e. For clarity I am comparing it to 134a as the old junk. Not sure how 152a stacks up in safety and properties.
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Apr 10, 2016 14:42
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Minarchist posted:If you crash your car and wind up stuck in a burning wreck you might get to deal with HF gas it's actually a safety feature, your now rubberised bones will make it so much easier to extract you from the wreck of burning metal and plastic that was your car. instead of using the jaws of life they'll just stretch armstrong you out of the closest AC vent. Moist von Lipwig has a new favorite as of 17:40 on Apr 10, 2016 |
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Apr 10, 2016 15:41
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Although I am a random stranger on the Internet, I can safely say that it would be a terrible idea to burn that to see what happens.
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Apr 10, 2016 17:35
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Rigged Death Trap posted:WRONG A BUNCH OF THINGS DONT Has this been tried as a rocket fuel? I know they got specific impulse over 500 seconds with hydrogen-fluorine-lithium, but I wonder if KrF2's stronger oxidizing ability would cancel out the performance losses from how heavy krypton is. Edit: KrF4 would be even better, since it has a higher proportion of fluorine to krypton while potentially being a stronger oxidizer.
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Apr 10, 2016 20:17
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LostCosmonaut posted:Has this been tried as a rocket fuel? I know they got specific impulse over 500 seconds with hydrogen-fluorine-lithium, but I wonder if KrF2's stronger oxidizing ability would cancel out the performance losses from how heavy krypton is. Neither is stable at room temperature. Both need to be stored as solids at dry ice temperatures. They wouldn't be very practical as rocket fuels.
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Apr 10, 2016 22:17
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Kinetica posted:Although I am a random stranger on the Internet, I can safely say that it would be a terrible idea to burn that to see what happens. We didn't send men to the moon with that attitude.
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Apr 10, 2016 22:53
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LostCosmonaut posted:Has this been tried as a rocket fuel? I believe we have learned from this very thread that the answer to this question is always yes.
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