What experience allows you to estimate the molecular size of olive oil?

Experiments with liquids helped to estimate the size of molecules. Take a small drop of olive oil on the tip of a thin needle and touch the surface of clean water. A drop with a volume of about 1 mm3, spreading out, creates a layer with a surface area of about 10,000 mm. The thickness of such a layer can be obtained by dividing the droplet volume by the surface area, ie, 1 mm3: 10,000 mm2 = 0.0001 mm. This layer is formed by about 100 molecules in thickness. Then the size of one molecule will be one millionth of a millimeter (0.000001 mm, or 10-9 m).