get heavier vs spread out

get heavier

spread out

adj
  • Covering a wide area of space or long period of time. 

  • Far apart, not close to each other - far apart, extended over an expanse of space or time. 

verb
  • Become further apart. 

  • To place items further apart. 

How often have the words get heavier and spread out occurred in a corpus of books? (source: Google Ngram Viewer )