1 00:00:00,120 --> 00:00:03,000 Speaker 1: Hi. I am Tracy V. Wilson and I'm Holly Fry. 2 00:00:03,080 --> 00:00:05,360 Speaker 1: We are the co hosts of the Stuff You Missed 3 00:00:05,360 --> 00:00:08,240 Speaker 1: in History Class podcast from how Stuff Works dot com. 4 00:00:08,280 --> 00:00:10,240 Speaker 1: And as you might suspect from the name, what we 5 00:00:10,320 --> 00:00:12,400 Speaker 1: like to talk about are the things that are of 6 00:00:12,840 --> 00:00:15,920 Speaker 1: historical significance but maybe you didn't hear about in your 7 00:00:15,960 --> 00:00:19,400 Speaker 1: standard history class. So sometimes they are famous figures and 8 00:00:19,400 --> 00:00:21,800 Speaker 1: we're talking about the lesser known parts of their lives. 9 00:00:21,920 --> 00:00:24,840 Speaker 1: Sometimes they are people in groups and places that are 10 00:00:24,840 --> 00:00:28,800 Speaker 1: often overlooked in history class. Lots of cool stuff, so 11 00:00:28,960 --> 00:00:32,640 Speaker 1: come and join us. Hey, everybody, this is Christian Seger. 12 00:00:32,920 --> 00:00:35,360 Speaker 1: I love learning. That's why I do brain Stuff, and 13 00:00:35,360 --> 00:00:38,080 Speaker 1: I'm assuming that's why you listen to brain Stuff. It's 14 00:00:38,120 --> 00:00:41,040 Speaker 1: also why I'm a fan of the Great Courses Plus 15 00:00:41,440 --> 00:00:44,840 Speaker 1: video learning service. Not only can you learn about any 16 00:00:44,880 --> 00:00:47,800 Speaker 1: topic that interests you there, you can also learn new 17 00:00:47,880 --> 00:00:51,600 Speaker 1: skills or expand on hobbies. They have everything from courses 18 00:00:51,640 --> 00:00:55,160 Speaker 1: about how to cook, take better photos, speak another language, 19 00:00:55,200 --> 00:00:57,760 Speaker 1: play chess. You can even learn how to draw. 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Some of my favorites 25 00:01:16,280 --> 00:01:18,040 Speaker 1: that I've seen on there are things like how to 26 00:01:18,080 --> 00:01:23,399 Speaker 1: play chess, how to master photography, and how to understand investments. 27 00:01:23,680 --> 00:01:27,319 Speaker 1: And now, for brain Stuff listeners, the Great Courses Plus 28 00:01:27,400 --> 00:01:31,520 Speaker 1: is offering a special opportunity to stream hundreds of their 29 00:01:31,560 --> 00:01:35,360 Speaker 1: courses free for one month. When you sign up, find 30 00:01:35,440 --> 00:01:38,480 Speaker 1: courses that truly interest you and start learning more today. 31 00:01:38,520 --> 00:01:40,240 Speaker 1: The way you do it is you sign up to 32 00:01:40,319 --> 00:01:43,399 Speaker 1: get a free trial of the Great Courses Plus by 33 00:01:43,440 --> 00:01:48,080 Speaker 1: going to the Great Courses Plus dot com slash brain Stuff. 34 00:01:48,200 --> 00:01:52,600 Speaker 1: That's the Great Courses Plus dot com slash brain Stuff. 35 00:01:55,040 --> 00:02:02,680 Speaker 1: Welcome to brain Stuff from How Stuff Works. My name 36 00:02:02,760 --> 00:02:07,000 Speaker 1: is Christian, My world is fire and blood. Once I 37 00:02:07,080 --> 00:02:11,320 Speaker 1: hunked the horn of my interceptive Pursuit special, it's hard 38 00:02:11,360 --> 00:02:16,720 Speaker 1: to know who was more crazy, me or everyone else. No, really, 39 00:02:16,760 --> 00:02:20,520 Speaker 1: when people haunt car horns, they're pretty freaking aggressive. Research 40 00:02:20,600 --> 00:02:23,600 Speaker 1: shows were more likely to do it when it's hot outside, 41 00:02:23,800 --> 00:02:27,119 Speaker 1: when it's a week day, and if you're male, that's right. 42 00:02:27,360 --> 00:02:30,120 Speaker 1: War boys here in the US, your run of the 43 00:02:30,160 --> 00:02:32,800 Speaker 1: mill car horn is a hundred and ten decibels of 44 00:02:32,840 --> 00:02:36,880 Speaker 1: sustained noise. While the vehicle horns of yesteryear had different 45 00:02:36,880 --> 00:02:41,040 Speaker 1: combinations of notes, today they're mostly regulated to sound the same, 46 00:02:41,320 --> 00:02:44,600 Speaker 1: and the law requires you to have a car horn 47 00:02:44,919 --> 00:02:48,720 Speaker 1: if they're so important. Let's talk about how car horns work. 48 00:02:49,480 --> 00:02:53,240 Speaker 1: Typical car horns these days are electro mechanical. There are 49 00:02:53,280 --> 00:02:57,560 Speaker 1: two horns per vehicle, usually each sounding at a different 50 00:02:57,600 --> 00:03:01,960 Speaker 1: pitch to produce a cord. These horns generally consist of 51 00:03:02,000 --> 00:03:06,760 Speaker 1: a spring, steel diaphragm, a coiled wire, a switch, and 52 00:03:06,919 --> 00:03:11,120 Speaker 1: housing that amplifies sound like a megaphone. All of this 53 00:03:11,200 --> 00:03:15,519 Speaker 1: is mounted somewhere behind your vehicle's grill. So when you 54 00:03:15,560 --> 00:03:18,080 Speaker 1: slam your hand on that steering wheel button with a 55 00:03:18,120 --> 00:03:21,680 Speaker 1: little trumpet symbol on it, it sends an electrical current 56 00:03:21,840 --> 00:03:25,359 Speaker 1: through a relay and onto a copper coil that supplies 57 00:03:25,400 --> 00:03:29,160 Speaker 1: electricity to the horn. To create such a loud sound 58 00:03:29,280 --> 00:03:32,960 Speaker 1: takes a lot of energy. In fact, the only accessory 59 00:03:33,040 --> 00:03:36,120 Speaker 1: that uses more juice in your car is the starter. 60 00:03:36,680 --> 00:03:40,920 Speaker 1: The electrical current surging into the horn creates a magnetic field. 61 00:03:40,960 --> 00:03:45,840 Speaker 1: This field causes the flat circular diaphragm inside to oscillate. 62 00:03:46,240 --> 00:03:49,880 Speaker 1: The oscillation is set up by the diaphragm flexing to 63 00:03:50,000 --> 00:03:54,840 Speaker 1: its mechanical limit and then releasing back past its neutral position, 64 00:03:54,920 --> 00:03:58,480 Speaker 1: only to be pulled forward again. This functions by using 65 00:03:58,520 --> 00:04:01,640 Speaker 1: the basic law of elasticity, also known as Hook's law 66 00:04:02,000 --> 00:04:05,240 Speaker 1: because it was formulated in the seventeenth century by an 67 00:04:05,240 --> 00:04:09,080 Speaker 1: English scientist named Robert Hook. The law states that the 68 00:04:09,160 --> 00:04:12,320 Speaker 1: strain of a body is proportional to the stress applied 69 00:04:12,520 --> 00:04:15,680 Speaker 1: to the body. What this means for the car horn 70 00:04:16,120 --> 00:04:19,720 Speaker 1: is that it's diaphragm will oscillate continuously as long as 71 00:04:19,720 --> 00:04:23,040 Speaker 1: the current is applied. There are also other types of 72 00:04:23,040 --> 00:04:26,919 Speaker 1: horns used in vehicles, air horns, Clason's whistles similar to 73 00:04:27,040 --> 00:04:31,200 Speaker 1: organ pipes, and even sirens like we see on emergency vehicles, 74 00:04:31,240 --> 00:04:35,240 Speaker 1: but the electro magnetic car horn is the most common one. 75 00:04:35,520 --> 00:04:38,279 Speaker 1: You're going to find out there in the waste land. 76 00:04:38,640 --> 00:04:41,120 Speaker 1: Now that you're armed with this knowledge, you should be 77 00:04:41,200 --> 00:04:49,680 Speaker 1: ready to grab the sun and ride into Valhalla. Check 78 00:04:49,720 --> 00:04:51,760 Speaker 1: out the brain stuff channel on YouTube, and for more 79 00:04:51,800 --> 00:04:54,320 Speaker 1: on this and thousands of other topics, visit how stuff 80 00:04:54,360 --> 00:05:08,960 Speaker 1: works dot com.