heating vs liquefaction

heating

noun
  • The act of making something hot. 

  • A system that raises the temperature of a room or building. Compare heater. 

adj
  • Causing heat. 

liquefaction

noun
  • Process of being, or state of having been, made liquid (from either a solid or a gas) 

  • The liquid or semiliquid that results from this process. 

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