A 19th-century physicist, Lord Rayleigh, was the first to determine the size of individual molecules. He did it using little more than oil, water, and a back-of-the-envelope calculation.
Love the message about the power of collaboration across periods of time. Franklin and Rayleigh’s two different attributes, keen observation (noticing the subdued wakes) and diligent experimentation had to be connected through scientific discourse for this sparkling insight to emerge!
The “prismatic” colors Franklin witnessed did not come from a single layer of oil molecules as thin film interference of light happens with layers in the order of a few hundred nanometres. Colors form as the oil layer spreads and thins but once it's spread into a monolayer there's no colors as the layer is too thin to produce interference.
Agnes Pockels was also a pioneer in the field, she studied interfacial phenomena in her kitchen and wrote a letter to Lord Rayleigh who helped her publish her results on oil monolayers
Did Loschmidt experimentally determine molecular sizes, or calculate dimensions from theory? My understanding is it was the latter. Please share a source so we can learn more!
Here's a link... seems to be open access, including the PDF version of the article. Experiments had been done by others, and he used their data to deduce the size of molecules, etc. This shouldn't detract from the great significance of his work.
Great story, thank you for sharing… uplifting 🍀💯 Ben Franklin was certainly an under appreciated genius
Love the message about the power of collaboration across periods of time. Franklin and Rayleigh’s two different attributes, keen observation (noticing the subdued wakes) and diligent experimentation had to be connected through scientific discourse for this sparkling insight to emerge!
Very insightful. It is so good that we are shining a light on under-appreciated discoveries and the people behind them.
The “prismatic” colors Franklin witnessed did not come from a single layer of oil molecules as thin film interference of light happens with layers in the order of a few hundred nanometres. Colors form as the oil layer spreads and thins but once it's spread into a monolayer there's no colors as the layer is too thin to produce interference.
Agnes Pockels was also a pioneer in the field, she studied interfacial phenomena in her kitchen and wrote a letter to Lord Rayleigh who helped her publish her results on oil monolayers
I'm a great admirer of Lord Rayleigh's, but the first to determine the size of molecules\atoms was Loschmidt, in 1865.
Did Loschmidt experimentally determine molecular sizes, or calculate dimensions from theory? My understanding is it was the latter. Please share a source so we can learn more!
Here's a link... seems to be open access, including the PDF version of the article. Experiments had been done by others, and he used their data to deduce the size of molecules, etc. This shouldn't detract from the great significance of his work.
https://doi.org/10.1063/1.1366067