1. Heavy water (Deuterium oxide, D2O) is a form of water containing a larger than normal amount of the hydrogen isotope deuterium.
2. It was discovered (isolated and characterized) by the American chemist Harold C. Urey in 1931, for which he won the Nobel Prize in Chemistry in 1934.
3. Heinrich Hertz worked on electromagnetic waves. G. Mendel is the father of genetics. Joseph Priestley discovered oxygen.