How was Johannes Diderik van der Waals awarded the Nobel Prize?

Name: Johannes Diderik van der Waals. 
Country: Netherlands.
Date of Birth: 23 November 1837.
Died: 8 March 1923.
The subject of Study: Gas-liquid van der Waals equation.
Noble Prize Year: Nobel Prize for Physics in 1910 for their research on the gaseous and liquid states of matter.