1 00:00:00,440 --> 00:00:03,480 Speaker 1: I'm at, I'm null, I'm Ben, and we are stuff 2 00:00:03,520 --> 00:00:06,080 Speaker 1: they don't want you to know. Each week we cover 3 00:00:06,160 --> 00:00:09,719 Speaker 1: the latest and strangest in fringe science, government cover ups, 4 00:00:09,800 --> 00:00:13,399 Speaker 1: allegations of the paranormal, and more. New episodes come out 5 00:00:13,440 --> 00:00:16,880 Speaker 1: every Friday on iTunes, Spotify, Google Play, and anywhere else 6 00:00:16,960 --> 00:00:23,680 Speaker 1: you get your podcasts. Welcome to brain Stuff from How 7 00:00:23,720 --> 00:00:31,920 Speaker 1: Stuff Works. Hey, I'm Christian Seger, and this is brain Stuff. 8 00:00:32,000 --> 00:00:35,800 Speaker 1: It's fair to say that light bulbs their revolutionary invention, 9 00:00:36,159 --> 00:00:39,120 Speaker 1: and it's tough to imagine the modern world without them. 10 00:00:39,120 --> 00:00:43,800 Speaker 1: But they're not perfect. Incandescent bulbs produce way more heat 11 00:00:43,840 --> 00:00:47,919 Speaker 1: than they do light, and their successors, compact fluorescent lamps 12 00:00:48,200 --> 00:00:53,519 Speaker 1: hereafter referred to as CFLs, Well, those have their own disadvantages. 13 00:00:53,800 --> 00:00:56,960 Speaker 1: In office buildings around the world, the weird buzz of 14 00:00:57,120 --> 00:01:01,840 Speaker 1: CFL is slowly driving people into madness. So what is 15 00:01:01,880 --> 00:01:06,240 Speaker 1: going on with this weird noise? Anyhow, The buzz itself 16 00:01:06,360 --> 00:01:09,800 Speaker 1: is a product of magnet restriction, but for that to 17 00:01:09,880 --> 00:01:12,040 Speaker 1: make sense, we're going to need to look at how 18 00:01:12,080 --> 00:01:15,640 Speaker 1: these things actually work. The central element in a CFL 19 00:01:15,840 --> 00:01:19,320 Speaker 1: is a glass tube filled with an inert gas usually 20 00:01:19,520 --> 00:01:23,399 Speaker 1: are gone and mercury. The inside of the tube is 21 00:01:23,480 --> 00:01:27,400 Speaker 1: coated with a phosphor powder, which influences the ultimate color 22 00:01:27,520 --> 00:01:30,240 Speaker 1: of the light. There are electrodes at either end of 23 00:01:30,280 --> 00:01:33,400 Speaker 1: the tube and they're wired to an electrical circuit. And 24 00:01:33,480 --> 00:01:37,120 Speaker 1: still with me. When you activate the lamp, a current 25 00:01:37,360 --> 00:01:42,120 Speaker 1: moves through the electrodes. There's considerable voltage across the electrodes, 26 00:01:42,200 --> 00:01:45,039 Speaker 1: so electrons move from one end of the tube to 27 00:01:45,160 --> 00:01:49,240 Speaker 1: the other. This vaporizes the mercury, changing some of it 28 00:01:49,280 --> 00:01:52,640 Speaker 1: from a liquid to a gas. As the electrons and 29 00:01:52,720 --> 00:01:56,040 Speaker 1: other charged atoms move across the tube, some of them 30 00:01:56,080 --> 00:02:01,640 Speaker 1: collide with gaseous mercury atoms. These visions excite the atoms, 31 00:02:01,720 --> 00:02:05,000 Speaker 1: bumping the electrons up to higher energy levels, and when 32 00:02:05,000 --> 00:02:08,520 Speaker 1: the electrons return to their original energy level, they release 33 00:02:08,840 --> 00:02:13,600 Speaker 1: light photons. However, most of this is ultraviolet light. Before 34 00:02:13,600 --> 00:02:16,280 Speaker 1: it becomes useful to us, it needs to be converted 35 00:02:16,320 --> 00:02:20,040 Speaker 1: to visible light. This is where that phosphor powder comes in. 36 00:02:20,320 --> 00:02:24,720 Speaker 1: The ultraviolet light causes phosphor to fluoresce or produce visible light. 37 00:02:25,200 --> 00:02:29,079 Speaker 1: Manufacturers can change the color of visible light emitted by 38 00:02:29,160 --> 00:02:33,000 Speaker 1: using different combinations of phosphors. Here's where it gets a 39 00:02:33,080 --> 00:02:36,680 Speaker 1: little tricky. The current inside the tube has to be 40 00:02:36,800 --> 00:02:40,640 Speaker 1: limited so that it doesn't rise precipitously and trip the 41 00:02:40,680 --> 00:02:44,320 Speaker 1: local circuit breaker. Fluorescent lights use ballasts to keep the 42 00:02:44,360 --> 00:02:48,119 Speaker 1: current in check. The original ballasts for fluorescent bulbs are 43 00:02:48,160 --> 00:02:53,440 Speaker 1: electromagnetic devices similar to inductors. Imagine a bunch of wire 44 00:02:53,600 --> 00:02:56,880 Speaker 1: wound around an iron core. A change in the flow 45 00:02:57,000 --> 00:03:00,560 Speaker 1: of alternate currents through the inductor creates a magnetic field. 46 00:03:00,960 --> 00:03:05,160 Speaker 1: This field also changes, creating a changing voltage in the wire, 47 00:03:05,680 --> 00:03:09,440 Speaker 1: slowing the currents flow. So a ballast is useful because 48 00:03:09,440 --> 00:03:13,480 Speaker 1: it prevents fluorescent lights from well blowing things up. Think 49 00:03:13,520 --> 00:03:15,760 Speaker 1: of it like a break in a car, except well, 50 00:03:15,800 --> 00:03:18,760 Speaker 1: I guess okay, it can stop small explosions. Breaks and 51 00:03:18,760 --> 00:03:22,160 Speaker 1: cars can also stop small explosions. Never mind. The point 52 00:03:22,200 --> 00:03:25,120 Speaker 1: is that the ballast can also make that buzzing noise 53 00:03:25,280 --> 00:03:29,520 Speaker 1: through an effect called magnetostriction. This happens when the magnetic 54 00:03:29,560 --> 00:03:33,400 Speaker 1: field produced by the ballast physically squeezes that iron core. 55 00:03:33,880 --> 00:03:37,800 Speaker 1: In the United States, the light is operating at sixty hurts. 56 00:03:37,840 --> 00:03:41,520 Speaker 1: Thanks to magnetostriction, the core can be squeezed and released 57 00:03:41,560 --> 00:03:45,040 Speaker 1: at twice that rate. A hundred and twenty hurts, creating 58 00:03:45,080 --> 00:03:48,680 Speaker 1: the buzz, known and often hated by office workers around 59 00:03:48,720 --> 00:03:51,640 Speaker 1: the world. Now for the next question, how do you 60 00:03:51,720 --> 00:03:54,560 Speaker 1: get rid of the buzz? Well, one of the simplest 61 00:03:54,560 --> 00:03:57,640 Speaker 1: solutions can be to replace the bulb itself. If you 62 00:03:57,680 --> 00:04:00,360 Speaker 1: have an older fluorescent light, you may want to replace 63 00:04:00,440 --> 00:04:03,000 Speaker 1: the ballast, But keep in mind that if the device 64 00:04:03,040 --> 00:04:05,800 Speaker 1: begins to fail again, the buzz is going to return. 65 00:04:06,160 --> 00:04:08,720 Speaker 1: And that annoying buzz is not the only thing people 66 00:04:08,760 --> 00:04:12,520 Speaker 1: hate about compact fluorescence. The odd colors can give people headaches, 67 00:04:12,800 --> 00:04:16,839 Speaker 1: and the mercury inside can pose some serious health risks. Luckily, 68 00:04:16,920 --> 00:04:20,680 Speaker 1: there's some good news. We're not stuck choosing between inefficient 69 00:04:20,800 --> 00:04:25,479 Speaker 1: incandescent bulbs and humming fluorescent ones. Instead, we can use 70 00:04:25,640 --> 00:04:28,360 Speaker 1: l E ED bulbs. L E D bulbs may well 71 00:04:28,400 --> 00:04:31,080 Speaker 1: be the light bulbs of the future, but that's a 72 00:04:31,120 --> 00:04:38,080 Speaker 1: story for a different thing. Check out the brain stuff 73 00:04:38,120 --> 00:04:40,440 Speaker 1: channel on YouTube, and for more on this and thousands 74 00:04:40,480 --> 00:04:56,680 Speaker 1: of other topics, visit how stuff works dot com.