(classical music)
- [Voiceover] My name is Lauren.
My world is fire and blood.
Once, I honked the horn of my
Interceptor Pursuit Special.
It's hard to know who was more crazy.
Me, or everyone else.
- [Voiceover] Hello?
- No, really, when people honk car horns
they're pretty freakin' aggressive.
Research shows we're more likely to do it
when it's hot outside,
when it's a weekday,
and if you're male.
That's right, War Boys.
Here in the United States,
your run-of-the-mill car horn
is 110 decibels of sustained noise.
While the vehicle horns of yesteryear
had different combinations of notes,
today, they're mostly
regulated to sound the same.
And the law requires
you to have a car horn.
Typical car horns these
days are electromechanical.
There are usually two horns per vehicle,
each sounding at a different
pitch to produce a chord.
These horns generally consist of
a spring steel diaphragm,
a coiled wire, a switch,
and housing that amplifies
sound, like a megaphone.
All of this is mounted somewhere
behind your vehicle's grill.
So, when you slam your hand
on that steering wheel button
with the little trumpet symbol,
it sends an electrical
current through a relay
and onto a copper coil
that supplies electricity to the horn.
To create such a loud sound
takes a lot of energy.
In fact, the only accessory
that uses more juice
in your War Rig is the starter.
The electrical current surging
into the horn creates a magnetic field.
This field causes the
flat, circular diaphragm
inside to oscillate.
The oscillation is set
up by the diaphragm,
flexing to it's mechanical limit,
and then releasing back
past it's neutral position,
only to be pulled forward again.
This functions by using the
basic law of elasticity,
also known as Hooke's Law
because it was formulated
in the 17th century by
an English scientist
named Robert Hooke.
The law states that the strain of a body
is proportional to the
stress applied to the body.
Or what this means for the car horn,
is that it's diaphragm
will oscillate continuously
as long as the current is applied.
There are also other types
of horns used in vehicles.
Air horns, klaxons, whistles
similar to organ pipes,
and even sirens like we
see on emergency vehicles.
But the electromagnetic car
horn is the most common one
you're going to find out
there in the Wasteland.
Now that you're armed with this knowledge
you should be ready to grab the sun
and ride into Valhalla!
But I've got a question,
when was the last or
the most memorable time
that you honked your car horn?
Let me know in the comments.
And for more information
about chrome, guzzling,
and loud noises, don't forget to subscribe
and visit us at howstuffworks.com.
