The harmonica is a wind instrument often used in blues, jazz, country and rock and roll. There are many different kinds of harmonicas, but most beginners start with a “diatonic harmonica" (sometimes called a “blues harp") in the key of C, since they are considered one of the easiest types to play.

The harmonica is played by placing the lips over little holes called "reed chambers." Each reed chamber has multiple reeds, which are fastened at one end and loose at the other.

Musicians use their breath to blow into or draw air out of the harmonica. The pressure caused by forcing air into or out of the reed chambers causes the loose ends of the reeds to vibrate up and down, creating sound.

Unlike oboes, clarinets and bassoons, which require manual tuning, the harmonica's reeds are pretuned, which means each reed makes a particular tone. Longer reeds make deep, low sounds. Shorter reeds make up the high notes.

Blowing into the harmonica produces one note, while drawing air from the harmonica produces another. By doing this, a player is able to play 19 notes on a diatonic harmonica.

Musicians often use a technique called "vibrato" while playing the harmonica. By opening and closing their hands quickly around the harmonica, musicians can create vibrato, which gives the notes a shaking sound.

Blues players also create vibrato with a harmonica by shaking their heads, which moves their lips very quickly between two of the holes on the harmonica.

Would you believe some doctors have even used the harmonica as a medical treatment?

As musicians inhale and exhale to play the harmonica, they breathe against resistance.This means they must use and develop their diaphragm and lungs, causing them to breathe deeply in order to make music.

Patients with lung problems use machines that help them exercise the same muscles. Some doctors have found that using the harmonica gives patients more motivation to practice their lung exercises and have added it to their treatment plans!

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