insulate vs intervene

insulate

verb
  • To separate, detach, or isolate. 

  • To separate a body or material from others, e.g. by non-conductors to prevent the transfer of electricity, heat, etc. 

intervene

verb
  • To become involved in a situation, so as to alter or prevent an action. 

  • To occur, fall, or come between, points of time, or events. 

  • To say (something) in the middle of a conversation or discussion between other people, or to respond to a situation involving other people. 

  • To come between, or to be between, persons or things. 

  • In a suit to which one has not been made a party, to put forward a defense of one's interest in the subject matter. 

  • To occur or act as an obstacle or delay. 

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