An age-old way of calming troubled water is to pour a tiny amount of oil onto the body of water and let it spread out forming a calming layer. Benjamin Franklin observed that the oil spot expands only up to a point and then grows no more. He suspected the truth that the oil had reached a monolayer of molecules and could expand no further. If we take his estimate of two teaspoons of fine oil per acre of calmed surface area as roughly correct … approximately how big must the oil molecule be?

An age-old way of calming troubled water is to pour a tiny amount of oil onto the body of water and let it spread out forming a calming layer. Benjamin Franklin observed that the oil spot expands only up to a point and then grows no more. He suspected the truth that the oil had reached a monolayer of molecules and could expand no further. If we take his estimate of two teaspoons of fine oil per acre of calmed surface area as roughly correct … approximately how big must the oil molecule be? (an upper limit on size!)
1 tsp = 4.93 cm3