Birds flap their wings as they fly, also moving them up and down. The movement of their wings, however, is so much slower than that of bee’s wings that it creates very little sound. The honeybee moves its wings back and forth more than 400 times a second, sometimes more than 26,000 times a minute. Because these movements are so rapid, we can not sort out the individual sounds, but hear the constant humming.
The word “humming”, like the word “pop”, imitates the sound it describes. There are many such sound-imitating words in most languages.
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