Johannes Diderik van der Waals

Johannes Diderik van der Waals was a Dutch theoretical physicist born 23 November 1837, who started his career teaching school before becoming the first physics professor at the University of Amsterdam in 1877. In his 1873 thesis, he tackled the problem of real gases behaving differently than ideal theory predicted, introducing an equation of state that accounted for the finite volume of molecules and the forces between them — at a time when many physicists, led by Ernst Mach and Wilhelm Ostwald, denied molecules even existed. His equation revolutionized the field: it affirmed the reality of m…