cool down vs encourage

cool down

verb
  • To cause (someone) to become less agitated or excited. 

  • To become cooler; to be reduced in temperature. 

  • To become less agitated or excited. 

  • To cause (something) to become cooler; to reduce the temperature of. 

  • To decrease in degree or intensity. 

encourage

verb
  • To mentally support; to motivate, give courage, hope or spirit. 

  • To spur on, strongly recommend. 

  • To foster, give help or patronage 

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