Johannes Diderik van der Waals (1837-1923) was a Dutch physicist. In important ways his life was similar to that of J. H. van't Hoff, who was 15 years his junior.

Van der Waals, the son of a carpenter, got a slower start than van't Hoff, the son of a doctor. He began as a primary school teacher and, lacking a classical education, could only graduate with an advanced degree after the law was changed to drop the requirements in Latin and Greek for science students.

Remember that it was 1874 when van't Hoff, while writing his doctoral thesis in Utrecht, published the little pamphlet Voorstel tot Uitbreiding der Tegenwoordige in de Scheikunde gebruikte Structuurformules in de Ruimte (Proposal for the Extension of Current Chemical Stuctures into Space). Once expanded and translated into French (1875) and German (1877), this pamphlet revolutionized organic chemistry.

In the previous year 1873, van der Waals's doctoral thesis in Leiden Over de continuïteit van de gas- en vloeistoftoestand (On the continuity of the gaseous and liquid states) proposed an empirical correction to the Equation of State for Ideal Gases (PV = nRT), to make it work for real gases at high pressure and low temperature, where attraction between molecules and their finite size (repulsive forces) come into play.

Despite the Dutch language, the thesis was an instant success, prompting James Clerk Maxwell to write,

there can be no doubt that the name of Van der Waals will soon be among the foremost in molecular science.
(Remember the less charitable reception of van't Hoff)

Indeed Van der Waals was awarded the Nobel Prize in Physics for this work in 1910.

In honor of this discovery, non-bonded attractive and repulsive forces between molecules are now called van der Waals forces. Forces due to some types of interaction (for example those among charges, dipoles, etc.), and sometimes even the attraction due to correlated electron motion (which is called Dispersion Force), are considered separately. Repulsion due overlap of filled orbitals, however, is always called van der Waals repulsion.

In 1887, when the Amsterdam Athanaeum became the new University of Amsterdam, van der Waals was appointed its first Professor of Physics; and van't Hoff, its first Professor of Chemistry, Mineralogy, and Geology.

Note: if we were Dutch we would capitalize the van when there are no first names or initials.
Click here for a biography and photo of van der Waals.