froth vs light water

froth

noun
  • foam 

  • Thousands of African children die each day: why do the newspapers continue to discuss unnecessary showbiz froth? 

  • Highly speculative investment. 

  • The idle rich; 

  • unimportant or insubstantial talk, events, or actions; drivel 

verb
  • To spit, vent, or eject, as froth. 

  • To cover with froth. 

  • (of a liquid) To bubble. 

  • To create froth in (a liquid). 

  • (literally) To spew saliva as froth; (figuratively) to rage, vent one's anger. 

light water

noun
  • Foam formed by water and a fluorocarbon surfactant, used in firefighting because it floats on flammable liquids lighter than water. 

  • Water in its standard form of H₂O, containing two protium hydrogen atoms, as opposed to heavy water. 

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