Science Fair Project Encyclopedia
A hum is a sound with a particular timbre (or sound quality), usually a monotone or with slightly varying tones, often produced by machinery in operation or by insects in flight. To hum is to produce such a noise, with humans vocally producing such a sound, humming, though most often with a melody.
The action of humming is produced simply by producing a wordless tone, such as in scat singing or vocables (wordless forms of singing), but with the mouth completely closed so that the sound emerges from the nose. This necessarily keeps the volume at a low level, so humming is often not useful in musical productions, but is nonetheless sometimes used.
Often, people hum either individually or when in group singing when they don't know the words or lyrics.
The contents of this article is licensed from www.wikipedia.org under the GNU Free Documentation License. Click here to see the transparent copy and copyright details