WEBVTT Kind: captions Language: en 00:00:01.020 --> 00:00:02.260 Hey, Vsauce. Michael here. 00:00:02.260 --> 00:00:06.500 And I'm in Anaheim at VidCon. I hope to see some of you here, because I 00:00:06.500 --> 00:00:11.240 like you guys. But I can't marry all of you. 00:00:11.700 --> 00:00:17.440 But if I did put a ring on it, what is the most precious thing you could make that ring 00:00:17.450 --> 00:00:20.180 out of? Silver, gold, platinum. 00:00:20.180 --> 00:00:26.170 Those are all fine, but I wanna know what is the rarest, most scarce thing on Earth 00:00:26.170 --> 00:00:29.830 that's stable and safe to wear I could make that ring out of. 00:00:29.830 --> 00:00:32.280 And I want it to be pure. I'm talking elemental. 00:00:32.720 --> 00:00:38.280 Well, luckily, I recently went to the University of Nottingham, home of Periodic Videos and 00:00:38.280 --> 00:00:44.880 experimented with some elements. First things first, zinc dissolved in mercury. 00:00:44.880 --> 00:00:48.160 This stuff is awesome, it's dense, it's heavy, it's liquid metal. 00:00:48.200 --> 00:00:54.380 It's cool, but even cooler is human urine. Thank you Neil. 00:00:54.380 --> 00:01:00.240 Of course I am just kidding. This is an aqueous solution of the metal vanadium. 00:01:00.240 --> 00:01:08.780 And when we mix vanadium in with the mercury and the zinc, the mercury helps the zinc give 00:01:08.789 --> 00:01:15.100 electrons to the vanadium. And is it gains more and more electrons, it 00:01:15.100 --> 00:01:18.979 changes colour. We're looking for purple. 00:01:19.580 --> 00:01:23.180 I love shaking this, it's crazy, it's like throwing me off balance. 00:01:23.180 --> 00:01:26.520 It's so heavy. Look at that. 00:01:32.060 --> 00:01:33.520 Thank you electrons. 00:01:37.260 --> 00:01:39.740 Those colours were beautiful, but vanadium 00:01:39.749 --> 00:01:43.049 is not that rare. I wanna get something more precious. 00:01:43.049 --> 00:01:47.329 And how about precious personally, like my dad? 00:01:47.329 --> 00:01:52.320 He's a chemical engineer who specifically works with and has a patent concerning one 00:01:52.329 --> 00:01:55.129 element. Sulphur. 00:01:55.129 --> 00:02:00.229 Of course a fun thing to do with sulphur is to make it bark like a dog. 00:02:00.229 --> 00:02:04.140 Here's what we're gonna do. We're gonna take a glass tube and fill it 00:02:04.149 --> 00:02:08.229 with laughing gas, nitrous oxide. We're gonna pour a little bit of water into 00:02:08.229 --> 00:02:12.950 the tube to cushion and protect the tube and then we're gonna pour in some liquid carbon 00:02:12.950 --> 00:02:16.070 disulphide. It's very volatile and will evaporate, giving 00:02:16.070 --> 00:02:22.580 us a mixture of gases inside this tube. Finally, I will light the top of the tube, 00:02:22.580 --> 00:02:27.340 causing the carbon disulphide to burn. And as it burns, the temperature and pressure 00:02:27.350 --> 00:02:31.660 in the tube will increase, causing the reaction to go faster and faster. 00:02:31.660 --> 00:02:33.920 It'll accelerate and bark. 00:02:37.500 --> 00:02:38.420 Wow. 00:02:41.100 --> 00:02:46.460 And look at all the sulphur on the sides of the tube. 00:02:46.460 --> 00:02:51.000 That reaction was fun and cool and colourful, but we're way off track here. 00:02:51.010 --> 00:02:55.850 Even though sulphur is precious and dear to my heart, it's not that rare at all. 00:02:55.850 --> 00:03:03.130 So let's get crazy and talk about astatine. Astatine is so rare here on Earth that we 00:03:03.130 --> 00:03:07.930 don't even know what it looks like. If you were to try to get enough astatine 00:03:07.930 --> 00:03:12.090 atoms together that you could see it with your own eyes, it would instantly vaporise 00:03:12.090 --> 00:03:17.140 itself because of its radioactive heat. The fact that it's so radioactive means it 00:03:17.140 --> 00:03:21.790 wouldn't be great as a ring, so let's move on to something a little bit more standard 00:03:21.790 --> 00:03:24.410 and see where it takes us. Gold. 00:03:24.410 --> 00:03:31.170 Gold, of course, is famous for its un-reactivity, which is why it's a great way to store your 00:03:31.170 --> 00:03:33.410 wealth. If you have a lot of gold laying around, the 00:03:33.410 --> 00:03:38.319 likelihood that it will combine with other elements and dissolve or rust or corrode is 00:03:38.319 --> 00:03:42.859 basically zero, with the exception of some special solutions. 00:03:42.860 --> 00:03:49.100 In particular, one discovered in 1300s with the fancy name "aqua regia." 00:03:49.100 --> 00:03:54.459 It's made out of hydrochloric acid and nitric acid and we're about to make some right now 00:03:54.459 --> 00:03:59.250 thanks to Neil from Periodic Videos. Of course, we're using this fume cover, because 00:03:59.250 --> 00:04:02.350 the fumes that come off the nitric acid are quite dangerous. 00:04:02.350 --> 00:04:08.350 It's the gas NO2 and if you inhale it, nitric acid forms in your lungs. 00:04:08.350 --> 00:04:11.760 So instead of doing that, let's put some gold in aqua regia. 00:04:11.770 --> 00:04:14.420 We're just gonna use this ancient priceless Egyptian relic. 00:04:14.420 --> 00:04:20.209 Let's go ahead and try this out. As the gold dissolves, what we wind up with 00:04:20.209 --> 00:04:27.319 in the evaporating dish is chloroauric acid. Auric coming from aurum, the Latin word for 00:04:27.319 --> 00:04:32.039 gold, which is why gold's symbol on the periodic table is Au. 00:04:32.760 --> 00:04:36.039 It's really sad to watch that gold dissolve away. 00:04:36.039 --> 00:04:39.800 I wish there was a way for us to just make other things into gold. 00:04:39.800 --> 00:04:41.960 Now I know what you're thinking. "Michael, that's alchemy." 00:04:41.960 --> 00:04:47.099 But alchemy is quite real. In today's particle accelerators we can smash 00:04:47.099 --> 00:04:52.919 particles together, creating elements. At the accelerator collider at GSI they can 00:04:52.919 --> 00:05:01.210 create gold by smashing particles together at a rate of 2 million gold atoms every second. 00:05:01.760 --> 00:05:06.860 That's pretty cool, right? Well, as you know, atoms are incredibly small. 00:05:06.860 --> 00:05:12.809 They're so small that even though GSI can make 2 million new gold atoms every single 00:05:12.809 --> 00:05:19.659 second, were they to leave the machine on at that rate for 50 million years they would 00:05:19.659 --> 00:05:28.219 only produce 1 gram of gold. Gold is rare and precious and expensive. 00:05:28.220 --> 00:05:35.020 But gold is 40% more common than iridium. And iridium is incredibly resilient. 00:05:35.020 --> 00:05:40.139 It doesn't dissolve in aqua regia and it's not even attacked by molten metals or silicates 00:05:40.139 --> 00:05:46.449 at high temperature, which is nice and ..., but not as pretty as cerium, which reacts at high 00:05:46.449 --> 00:05:52.259 temperature to form beautiful little sparkles. As we continue our journey to discover the 00:05:52.259 --> 00:05:57.099 rarest thing to make a ring out of, we've got to discuss osmium. 00:05:57.100 --> 00:06:03.040 This stuff is so rare there's fewer than one part per billion in our Earth's crust. 00:06:03.040 --> 00:06:07.180 But we're not done yet. Iridium and osmium are both in the platinum 00:06:07.180 --> 00:06:11.110 family. And if you take a look at platinum, it's much 00:06:11.110 --> 00:06:14.900 more common than both iridium and osmium, but there's something neat that I think we 00:06:14.900 --> 00:06:18.720 should consider. Stable isotopes. 00:06:19.020 --> 00:06:22.740 And it's one of the isotopes of platinum that will finish our story. 00:06:22.740 --> 00:06:27.080 Platinum-190. It's a stable isotope with half-life of over 00:06:27.080 --> 00:06:30.480 billion years that's non-reactive. It's fits all our criteria. 00:06:30.480 --> 00:06:36.919 A ring made of the scarcest, naturally occurring stable, non-reactive thing. 00:06:36.920 --> 00:06:41.400 So hey, it would be an awesome ring. Now, you're probably wondering, "Michael, 00:06:41.400 --> 00:06:45.460 why did you experiment with vanadium, sulphur, gold and cerium?" 00:06:45.469 --> 00:06:48.379 Well, here's what's interesting. Take a look at the periodic table and there's 00:06:48.379 --> 00:06:50.819 symbols. Ta-da! 00:06:50.819 --> 00:06:51.799 Vsauce. 00:06:51.799 --> 00:06:52.799 And as always, 00:06:52.800 --> 00:06:54.020 thanks for watching.