American scientist Irving Langmuir, in collaboration with scientist Katherine Blodgett and based on the studies of another scientist, Agnes Pockels, created the Langmuir tank in which, by releasing a known quantity of oily material into water, it expands into a patch until it reaches the thickness of a single molecule, held together only by van der Waals forces; knowing the initial volume and the final surface area, the molecular size can then be calculated.
