acoustics vs whirr

acoustics

noun
  • The science of sounds, teaching their nature, phenomena and laws. 

whirr

noun
  • A sibilant buzz or vibration; the sound of something in rapid motion. 

  • A bustle of noise and excitement. 

verb
  • To make a sibilant buzzing or droning sound. 

  • To cause (something) to make such a sound. 

  • To move or vibrate (something) with a buzzing sound. 

How often have the words acoustics and whirr occurred in a corpus of books? (source: Google Ngram Viewer )