The guitar is somewhat different. To play middle C on the guitar, you take your left-hand index finger and fret the 2nd string — that is, the 2nd string counting from the bottom as you hold the guitar — at the 1st fret. This action, however, doesn’t produce a sound. You must also strike or pluck that 2nd string with your right hand to audibly produce the note middle C.
The smallest interval (unit of musical difference in pitch) of the musical scale is the half step. On the piano, every adjacent key is a half-step apart, regardless of whether it’s black or white. To proceed by half steps on a keyboard instrument, you move your finger up or down to the next available key. On the guitar, frets represent these half steps. To go up or down by half steps on a guitar means to move your left hand one fret at a time, higher or lower on the neck.
Vibrating strings produce the different tones on a guitar. But you must be able to hear those tones, or you face one of those if-a-tree-falls-in-a-forest questions. For an acoustic guitar, that’s no problem, because an acoustic instrument provides its own amplifier in the form of the hollow sound chamber that boosts its sound . . . well, acoustically. But an electric guitar makes virtually no acoustic sound at all.
Well, a tiny bit, like a buzzing mosquito, but nowhere near enough to fill a stadium or anger your next-door neighbors.) An electric instrument creates its tones entirely through electronic means. The vibrating string is still the source of the sound, but a hollow wood chamber isn’t what makes those vibrations audible.
Instead, the vibrations disturb, or modulate, the magnetic field that the pickups — wire-wrapped magnets positioned underneath the strings — produce. As the vibrations of the strings modulate the pickup’s magnetic field, the pickup produces a tiny electric current that exactly reflects that modulation