Name: TED-ED】ギターを弾くことの物理学 -オスカー・フェルナンド・ペレス (【TED-Ed】The physics of playing guitar - Oscar Fernando Perez)
Uploaded: 2021-01-14T05:43:39.000Z
Duration: 4 min 55 s
Description: VoiceTubeの動画で発音を聞きながら英語表現を覚えよう！学べる英語：

but how exactly do the iconic contraptions in their hands

When you pluck a guitar string, you create a vibration called a standing wave.

Some points on the string, called nodes, don't move at all,

while other points, anti-nodes,  oscillate back and forth.

The vibration translates through the neck and bridge to the guitar's body,

where the thin and flexible wood vibrates,

jostling the surrounding air molecules together and apart.

These sequential compressions create sound waves,

and the ones inside the guitar mostly escape through the hole.

which translates them into electrical impulses

The pitch of that sound depends on the frequency of the compressions.

A quickly vibrating string will cause a lot of compressions close together,

and a slow vibration  produces a low-pitched sound.

Four things affect the frequency of a vibrating string:

the length, the tension, the density and the thickness.

Typical guitar strings  are all the same length,

and have similar tension, but vary in thickness and density.

Thicker strings vibrate more slowly, producing lower notes.

you actually create  several standing waves.

There's the first fundamental wave, which determines the pitch of the note,

but there are also waves called overtones,

whose frequencies  are multiples of the first one.

All these standing waves combine to form a complex wave with a rich sound.

Changing the way you pluck the string affects which overtones you get.

you get mainly the fundamental and the odd multiple overtones,

which have anti-nodes in the middle of the string.

If you pluck it near the bridge, you get mainly even multiple overtones

The familiar Western scale is based on the overtone series of a vibrating string.

When we hear one note played with another that has exactly twice its frequency,

they sound so harmonious that we assign them the same letter,

and define the difference between them as an octave.

The rest of the scale  is squeezed into that octave

whose frequency is each 2^(1/12) higher than the one before.

Each fret divides the string's remaining length by 2^(1/12),

making the frequencies  increase by half steps.

make it easier to produce the infinite frequencies between each note,

but add to the challenge  of playing in tune.

are custom tailored  to the chords we like to play

Guitar shapes and materials can also vary,

and both change the nature  and sound of the vibrations.

Playing two or more  strings at the same time

allows you to create new wave patterns like chords and other sound effects.

For example, when you play two notes whose frequencies are close together,

they add together to create a sound wave whose amplitude rises and falls,

producing a throbbing effect, which guitarists call the beats.

And electric guitars give you  even more to play with.

The vibrations still start in the strings,

but then they're translated  into electrical signals by pickups

and transmitted to speakers  that create the sound waves.

it's possible to process  the wave in various ways,

to create effects like distortion, overdrive, wah-wah, delay and flanger.

And lest you think that the physics  of music is only useful for entertainment,

Some physicists think that everything in the universe

is created by the harmonic series of very tiny, very tense strings.

be the extended solo  of some cosmic Jimi Hendrix?

Clearly, there's a lot more to strings than meets the ear.