Synopsis

• The term harmonic refers to the natural vibration of an object. All vibrating objects have harmonic properties, including people. The study of harmonics varies across many fields but is most dominantly represented in the study of electricity and in the study of music. In electricity, harmonics occur when currents interact at different frequencies. One adverse result of this can be heat. In music, harmonics have a much more dominate role. Wave lengths and their harmonic properties are an important part of the study of sound.
  
  

Overtones

• The natural frequencies at which waves can exist in a given medium are known as harmonics. If you imagine a jump rope moving as one segment, this is the first harmonic. If you imagine two jump ropes spinning at opposite frequencies, you have the second harmonic. Then, with three ropes in frequencies of thirds, you have the third harmonic, and so on. The additional ropes are referred to as overtones and almost all vibrating objects have overtones. Sound is a result of the interplay between overtones in a vibrating object.
  
  

Frequencies

• Each increasing harmonic represents a double of the frequency that came before it. For example, if a note resonates at 440 hz/second, the second harmonic of this fundamental note will resonate at 880 hz/second. The third will resonate at 1,320 hz/second and so on until sound becomes inaudible.
  
  

Harmonics in Music

• In music, notes represent frequencies and the same note on a higher or lower octave demonstrates a harmonic. However, harmonics occur in both minor and major keys so odd number harmonics will occur with an octave and a fifth above the previous harmonic. A fifth is seven semitones above the fundamental. In the previous example, the second harmonic is an octave above the fundamental; the third harmonics is an octave and a fifth above.
  
  An organ produces sounds by manipulating the harmonics of columns of air in the pipes. A pipe with one side closed and the other side open the wavelength is four times the length of the pipe. A pipe of this form has only odd harmonics. In a closed pipe all harmonics are possible. Brass and woodwind instruments work much the same way.
  
  In a stringed instrument the length of the string, how dense the string is, and how tight it is strung determines the pitch. Shorter tighter strings have higher pitches while longer looser strings have lower pitches. Fretting a stringed instrument adjusts the length and tension of the strings. By properly fretting a stringed instrument you can adjust the length and tension of the strings played to ensure harmonics in the form of a chord.