WAALS, JOHANNES DIEDERIK VAN DER

born Nov. 23, 1837, Leiden, Neth. died March 9, 1923, Amsterdam Dutch physicist, winner of the 1910 Nobel Prize for Physics for his research on the gaseous and liquid states of matter. His work made the study of temperatures near absolute zero possible. A self-educated man who took advantage of the opportunities offered by the University of Leiden, van der Waals first attracted notice in 1873 with his doctoral treatise "On the Continuity of the Liquid and Gaseous State," for which he was awarded a doctorate. In pursuing his research, he knew that the ideal-gas law could be derived from the kinetic theory of gases if it could be assumed that gas molecules have zero volume and that there are no attractive forces between them. Taking into account that neither assumption is true, in 1881 he introduced into the law two parameters (representing size and attraction) and worked out a more exact formula, known as the van der Waals equation. Since the parameters were distinct for each gas, he continued his work and arrived at an equation (the law of corresponding states) that is the same for all substances. It was this work that brought him the Nobel Prize and also led Sir James Dewar of England and Heike Kamerlingh Onnes of The Netherlands to the determination of the necessary data for the liquefaction of hydrogen and helium. Van der Waals was appointed professor of physics at the University of Amsterdam in 1877, a post he retained until 1907. The van der Waals forces, weak attractive forces between atoms or molecules, were named in his honour.