Speaker 1: Hi. I am Tracy V. Wilson and I'm Holly Fry.
Speaker 1: We are the co hosts of the Stuff You Missed
Speaker 1: in History Class podcast from how Stuff Works dot com.
Speaker 1: And as you might suspect from the name, what we
Speaker 1: like to talk about are the things that are of
Speaker 1: historical significance but maybe you didn't hear about in your
Speaker 1: standard history class. So sometimes they are famous figures and
Speaker 1: we're talking about the lesser known parts of their lives.
Speaker 1: Sometimes they are people in groups and places that are
Speaker 1: often overlooked in history class. Lots of cool stuff, so
Speaker 1: come and join us. Hey, everybody, this is Christian Seger.
Speaker 1: I love learning. That's why I do brain Stuff, and
Speaker 1: I'm assuming that's why you listen to brain Stuff. It's
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Speaker 1: Welcome to brain Stuff from How Stuff Works. My name
Speaker 1: is Christian, My world is fire and blood. Once I
Speaker 1: hunked the horn of my interceptive Pursuit special, it's hard
Speaker 1: to know who was more crazy, me or everyone else. No, really,
Speaker 1: when people haunt car horns, they're pretty freaking aggressive. Research
Speaker 1: shows were more likely to do it when it's hot outside,
Speaker 1: when it's a week day, and if you're male, that's right.
Speaker 1: War boys here in the US, your run of the
Speaker 1: mill car horn is a hundred and ten decibels of
Speaker 1: sustained noise. While the vehicle horns of yesteryear had different
Speaker 1: combinations of notes, today they're mostly regulated to sound the same,
Speaker 1: and the law requires you to have a car horn
Speaker 1: if they're so important. Let's talk about how car horns work.
Speaker 1: Typical car horns these days are electro mechanical. There are
Speaker 1: two horns per vehicle, usually each sounding at a different
Speaker 1: pitch to produce a cord. These horns generally consist of
Speaker 1: a spring, steel diaphragm, a coiled wire, a switch, and
Speaker 1: housing that amplifies sound like a megaphone. All of this
Speaker 1: is mounted somewhere behind your vehicle's grill. So when you
Speaker 1: slam your hand on that steering wheel button with a
Speaker 1: little trumpet symbol on it, it sends an electrical current
Speaker 1: through a relay and onto a copper coil that supplies
Speaker 1: electricity to the horn. To create such a loud sound
Speaker 1: takes a lot of energy. In fact, the only accessory
Speaker 1: that uses more juice in your car is the starter.
Speaker 1: The electrical current surging into the horn creates a magnetic field.
Speaker 1: This field causes the flat circular diaphragm inside to oscillate.
Speaker 1: The oscillation is set up by the diaphragm flexing to
Speaker 1: its mechanical limit and then releasing back past its neutral position,
Speaker 1: only to be pulled forward again. This functions by using
Speaker 1: the basic law of elasticity, also known as Hook's law
Speaker 1: because it was formulated in the seventeenth century by an
Speaker 1: English scientist named Robert Hook. The law states that the
Speaker 1: strain of a body is proportional to the stress applied
Speaker 1: to the body. What this means for the car horn
Speaker 1: is that it's diaphragm will oscillate continuously as long as
Speaker 1: the current is applied. There are also other types of
Speaker 1: horns used in vehicles, air horns, Clason's whistles similar to
Speaker 1: organ pipes, and even sirens like we see on emergency vehicles,
Speaker 1: but the electro magnetic car horn is the most common one.
Speaker 1: You're going to find out there in the waste land.
Speaker 1: Now that you're armed with this knowledge, you should be
Speaker 1: ready to grab the sun and ride into Valhalla. Check
Speaker 1: out the brain stuff channel on YouTube, and for more
Speaker 1: on this and thousands of other topics, visit how stuff
Speaker 1: works dot com.