1 00:00:01,800 --> 00:00:06,960 Speaker 1: Welcome to brain Stuff, a production of iHeart Radio, Hey 2 00:00:07,000 --> 00:00:11,960 Speaker 1: Brainstuff Lauren Bolg bomb here. Gallium is a rare, silvery 3 00:00:12,039 --> 00:00:14,720 Speaker 1: white element that can pull off one of the coolest 4 00:00:14,760 --> 00:00:19,239 Speaker 1: parlor tricks on the periodic table. At room temperature, gallium 5 00:00:19,320 --> 00:00:23,079 Speaker 1: is a shiny metallic solid that resembles pure aluminum. But 6 00:00:23,320 --> 00:00:25,320 Speaker 1: hold it in your hands for a few minutes and 7 00:00:25,480 --> 00:00:30,040 Speaker 1: this solid hunk of metal starts to melt. The melting 8 00:00:30,080 --> 00:00:33,560 Speaker 1: point of gallium is just eighty five point six degrees fahrenheit. 9 00:00:33,680 --> 00:00:36,640 Speaker 1: That's twenty nine point eight celsius, which means that it 10 00:00:36,720 --> 00:00:39,640 Speaker 1: melts into a mirror like puddle in your hot little hand. 11 00:00:40,400 --> 00:00:43,360 Speaker 1: In its liquid form, gallium looks a lot like mercury, 12 00:00:43,560 --> 00:00:47,240 Speaker 1: but gallium isn't toxic like mercury, so it's safer to handle, 13 00:00:47,440 --> 00:00:51,559 Speaker 1: though it can stain your skin. But gallium is so 14 00:00:51,720 --> 00:00:54,920 Speaker 1: much more than fodder for melt in your hand YouTube videos. 15 00:00:55,360 --> 00:00:58,840 Speaker 1: It's also a key ingredient in LED lights and the 16 00:00:58,920 --> 00:01:02,360 Speaker 1: go to semi condu after material for the powerful microchips 17 00:01:02,400 --> 00:01:06,360 Speaker 1: in your smartphone. The only thing stopping gallium from taking 18 00:01:06,400 --> 00:01:09,240 Speaker 1: over the electronics world is that it's very rare and 19 00:01:09,360 --> 00:01:14,880 Speaker 1: very expensive compared to silicon. Pure gallium doesn't exist in 20 00:01:14,920 --> 00:01:18,039 Speaker 1: its shiny elemental form in nature. It needs to be 21 00:01:18,080 --> 00:01:21,199 Speaker 1: extracted from minerals like box site through a multi step 22 00:01:21,280 --> 00:01:25,399 Speaker 1: chemical process. According to the U S Geological Survey, the 23 00:01:25,440 --> 00:01:28,680 Speaker 1: abundance of gallium in Earth's crust is a measly nineteen 24 00:01:28,760 --> 00:01:32,640 Speaker 1: parts per million. The silicon, by comparison, is two d 25 00:01:32,760 --> 00:01:37,399 Speaker 1: and eighty two thousand parts per million. In the year 26 00:01:37,480 --> 00:01:40,679 Speaker 1: eighteen fifty seven, a French chemist was the first person 27 00:01:40,760 --> 00:01:44,280 Speaker 1: to isolate and recognize gallium as a new element. He 28 00:01:44,440 --> 00:01:48,320 Speaker 1: named it after the Latin name for France, Gallia. But 29 00:01:48,560 --> 00:01:52,080 Speaker 1: four years before that, Russian chemist Dmitri mend to Leave 30 00:01:52,200 --> 00:01:56,240 Speaker 1: predictive gallium's existence. Mend to Leave, known as the father 31 00:01:56,320 --> 00:01:59,000 Speaker 1: of the periodic table, saw that there was a gap 32 00:01:59,080 --> 00:02:01,960 Speaker 1: in the table after aluminum, so he posited that a 33 00:02:02,040 --> 00:02:05,120 Speaker 1: missing element would share many of the properties of aluminum, 34 00:02:05,240 --> 00:02:09,280 Speaker 1: but with a different atomic structure. Amanda Leave was right, 35 00:02:09,760 --> 00:02:14,160 Speaker 1: but he couldn't have predicted how gallium's unusual qualities somewhere 36 00:02:14,200 --> 00:02:16,840 Speaker 1: between a metal and a non metal, would make it 37 00:02:16,960 --> 00:02:23,320 Speaker 1: ideal for modern electronics. Here's another cool and somewhat bizarre 38 00:02:23,480 --> 00:02:28,240 Speaker 1: fact about gallium. While it melts that the aforementioned hand temperature, 39 00:02:28,680 --> 00:02:32,480 Speaker 1: it doesn't boil until it reaches over a scorching four 40 00:02:32,560 --> 00:02:37,080 Speaker 1: thousand degrees fahrenheit or two thousand degrees celsius. It's exact 41 00:02:37,120 --> 00:02:40,560 Speaker 1: boiling point is listed differently in different chemistry texts, and 42 00:02:40,600 --> 00:02:43,640 Speaker 1: I'm not going to check it personally today, so that's 43 00:02:43,680 --> 00:02:48,240 Speaker 1: the ballpark. At any rate. This earns gallium the award 44 00:02:48,400 --> 00:02:52,680 Speaker 1: for maintaining the longest liquid phase of any element. So 45 00:02:52,960 --> 00:02:57,040 Speaker 1: why is this for? The article this episode is based on. 46 00:02:57,200 --> 00:02:59,720 Speaker 1: Has to Works reached out to the American Chemical Society 47 00:03:00,040 --> 00:03:03,240 Speaker 1: and spoke with Daniel Mandiola, a chemistry professor at the 48 00:03:03,360 --> 00:03:08,480 Speaker 1: University of Pennsylvania. He said, gallium is confused. It melts 49 00:03:08,480 --> 00:03:11,400 Speaker 1: at a low temperature, which is consistent with a light element, 50 00:03:11,639 --> 00:03:14,080 Speaker 1: but it boils at a very high temperature, which is 51 00:03:14,120 --> 00:03:17,680 Speaker 1: consistent with a very heavy element. Gallium doesn't know if 52 00:03:17,680 --> 00:03:19,480 Speaker 1: it wants to be a metal or a non metal. 53 00:03:21,400 --> 00:03:24,640 Speaker 1: Gallium's dual personality stems from where it sits on the 54 00:03:24,639 --> 00:03:28,320 Speaker 1: periodic table among two groups called the metalloids and the 55 00:03:28,520 --> 00:03:33,079 Speaker 1: post transition metals. Gallium is next in line after aluminum, 56 00:03:33,280 --> 00:03:36,800 Speaker 1: but it's atoms are far more independent than its shiny 57 00:03:36,840 --> 00:03:42,640 Speaker 1: foil uh. Also, aluminum is more electro positive trait of 58 00:03:42,680 --> 00:03:46,280 Speaker 1: true metals. That means it's more apt to release electrons 59 00:03:47,920 --> 00:03:51,720 Speaker 1: Like silicon. Gallium is a good conductor of electricity, but 60 00:03:51,920 --> 00:03:54,400 Speaker 1: not a great one. That's what makes both of these 61 00:03:54,400 --> 00:03:58,760 Speaker 1: metalloids prime candidates for semiconductors where the flow of electricity 62 00:03:58,840 --> 00:04:03,640 Speaker 1: needs to be control but using current manufacturing processes, A 63 00:04:03,640 --> 00:04:08,640 Speaker 1: wafer of gallium arsenide, the most popular gallium based semiconductor material, 64 00:04:09,200 --> 00:04:12,360 Speaker 1: is roughly a thousand times more expensive than the silicon 65 00:04:12,440 --> 00:04:17,839 Speaker 1: wafer because of gallium's rarity. Even though gallium is that 66 00:04:17,920 --> 00:04:21,720 Speaker 1: much more expensive than silicon, it's become a popular semiconductor 67 00:04:21,800 --> 00:04:26,599 Speaker 1: material in the latest generations of smartphones. Smartphones communicate with 68 00:04:26,640 --> 00:04:30,960 Speaker 1: cellular data networks using radio frequency chips or r F chips, 69 00:04:31,040 --> 00:04:33,960 Speaker 1: and r F chips made with gallium arsenide give off 70 00:04:34,040 --> 00:04:37,440 Speaker 1: less heat than silicon and can operate at higher frequency bands, 71 00:04:37,560 --> 00:04:40,720 Speaker 1: a requirement for five G networks. A little more than 72 00:04:41,680 --> 00:04:44,440 Speaker 1: of all the gallium consumed in the United States is 73 00:04:44,520 --> 00:04:47,039 Speaker 1: used to make r F chips and other types of 74 00:04:47,080 --> 00:04:52,640 Speaker 1: integrated circuits. However, one of the coolest applications of gallium 75 00:04:52,760 --> 00:04:56,040 Speaker 1: is in light emitting diodes, or l eds, which are 76 00:04:56,120 --> 00:04:59,320 Speaker 1: now used in everything from computer displays to traffic lights 77 00:04:59,360 --> 00:05:02,600 Speaker 1: to car headlights. L e d s are so popular 78 00:05:02,680 --> 00:05:06,400 Speaker 1: because they're super efficient they don't heat up. The first 79 00:05:06,520 --> 00:05:09,200 Speaker 1: visible light l eds were invented in the early nineteen 80 00:05:09,240 --> 00:05:13,400 Speaker 1: sixties when researchers at General Electric discovered the unique properties 81 00:05:13,440 --> 00:05:17,760 Speaker 1: of diodes made with various gallium alloys, that is, combinations 82 00:05:17,760 --> 00:05:22,680 Speaker 1: of gallium with arsenic, nitrogen, phosphorus, and other elements. In 83 00:05:22,760 --> 00:05:26,880 Speaker 1: a diode, electrons move through two layers of semiconductor material, 84 00:05:27,360 --> 00:05:29,839 Speaker 1: one with a positive charge and the other with a 85 00:05:29,920 --> 00:05:33,880 Speaker 1: negative charge. As free electrons from the negative side fill 86 00:05:34,200 --> 00:05:37,320 Speaker 1: holes in the positive side, they emit a photon of 87 00:05:37,400 --> 00:05:41,800 Speaker 1: light as a byproduct. Scientists have discovered that different gallium 88 00:05:41,839 --> 00:05:47,080 Speaker 1: alloys emit photons of different visible light frequencies. So gallium 89 00:05:47,160 --> 00:05:51,159 Speaker 1: arsenide and gallium phosphide produced red, orange, and yellow light, 90 00:05:51,480 --> 00:05:56,880 Speaker 1: while gallium nitride produces blue light. And not only do 91 00:05:57,160 --> 00:05:59,760 Speaker 1: l e d s produced light when connected to electricity, 92 00:06:00,160 --> 00:06:04,320 Speaker 1: but the process can be reversed. The special diodes inside 93 00:06:04,320 --> 00:06:08,280 Speaker 1: of solar cells are also made of galleum based semiconductors. 94 00:06:08,520 --> 00:06:11,839 Speaker 1: They take incoming light and separate it into free electrons 95 00:06:11,920 --> 00:06:15,320 Speaker 1: and holes, a generating voltage that can be saved in 96 00:06:15,360 --> 00:06:20,200 Speaker 1: a battery as electricity. The aerospace industry has been hot 97 00:06:20,200 --> 00:06:23,279 Speaker 1: on gallium for decades. All of the high end solar 98 00:06:23,320 --> 00:06:26,520 Speaker 1: panels that power satellites and long range spacecraft are made 99 00:06:26,600 --> 00:06:30,359 Speaker 1: with gallium arsenide, including the critical solar panels on the 100 00:06:30,400 --> 00:06:35,080 Speaker 1: Mars Exploration Rovers. At peak performance, the galleum based solar 101 00:06:35,080 --> 00:06:38,240 Speaker 1: cells on the Mars Rovers could produce nine hundred watt 102 00:06:38,240 --> 00:06:43,560 Speaker 1: hours of energy per martian day. But wait, there's more. 103 00:06:44,360 --> 00:06:48,000 Speaker 1: A Mendiola said. Medicine is beginning to use gallium too, 104 00:06:48,320 --> 00:06:52,400 Speaker 1: for detecting and treating certain types of cancers. Gallium sixty 105 00:06:52,400 --> 00:06:55,400 Speaker 1: seven is attracted to cells that replicate faster than normal, 106 00:06:55,640 --> 00:07:00,000 Speaker 1: which is what happens in a tumor. Gallium sixty seven 107 00:07:00,040 --> 00:07:03,560 Speaker 1: as a radioactive isotope of gallium that emits non toxic 108 00:07:03,720 --> 00:07:07,719 Speaker 1: gamma rays. A Radiologists can scan a patient's whole body 109 00:07:07,760 --> 00:07:11,440 Speaker 1: for tumors or inflammation from an infection by injecting gallium 110 00:07:11,480 --> 00:07:16,360 Speaker 1: sixty seven into their bloodstream. Because gallium sixty seven binds 111 00:07:16,400 --> 00:07:20,160 Speaker 1: to clumps, of fast growing cells. Those potential trouble spots 112 00:07:20,160 --> 00:07:22,360 Speaker 1: will then show up on a scan that's sensitive to 113 00:07:22,400 --> 00:07:27,280 Speaker 1: gamma rays. Gallium nitrate has also shown effectiveness in shrinking 114 00:07:27,400 --> 00:07:36,080 Speaker 1: and killing certain types of tumors, not just detecting them. 115 00:07:36,120 --> 00:07:39,400 Speaker 1: Today's episode is based on the article gallium boiled four 116 00:07:39,440 --> 00:07:42,400 Speaker 1: thousand and forty four degrees fahrenheit but will also melt 117 00:07:42,440 --> 00:07:44,680 Speaker 1: in your hand on how staff works dot Com. Written 118 00:07:44,680 --> 00:07:47,600 Speaker 1: by Dave Ruse. Brain Stuff is productive i Heart Radio 119 00:07:47,640 --> 00:07:49,600 Speaker 1: in partnership with how stuff works dot Com and it's 120 00:07:49,640 --> 00:07:53,040 Speaker 1: produced by Tyler Clang. Four more podcasts from my heart Radio. 121 00:07:53,280 --> 00:07:56,040 Speaker 1: Visit the iHeart Radio app, Apple Podcasts, or wherever you 122 00:07:56,080 --> 00:07:57,400 Speaker 1: listen to your favorite shows.