A Dutch physicist and professor at Amsterdam University. He completed a doctoral dissertation in 1873 at the University of Leiden entitled On the continuity of the liquid and gaseous states. The significance of this work was to account for many phenomena in vapours and liquids, which had already been observed by Thomas Andrews (1813–85). Van der Waals derived a new equation of state by postulating the existence of intramolecular forces and a finite molecular volume that predicted more accurately experimental data particularly under conditions near the critical point. He was awarded the Nobel Prize for Physics in 1910 and the weak attractions between molecules called van der Waals’ forces are named after him.