<P> The effect becomes clear for very small drop sizes, as a drop of 1 nm radius has about 100 molecules inside, which is a quantity small enough to require a quantum mechanics analysis . </P> <P> The two most abundant liquids on Earth are fresh water and seawater . This section gives correlations of reference data for the surface tension of both . </P> <P> The surface tension of pure liquid water in contact with its vapor has been given by IAPWS as </P> <Dl> <Dd> γ w = 235.8 (1 − T T C) 1.256 (1 − 0.625 (1 − T T C)) mN / m, (\ displaystyle \ gamma _ (\ text (w)) = 235.8 \ left (1 - (\ frac (T) (T_ (\ text (C)))) \ right) ^ (1.256) \ left (1 - 0.625 \ left (1 - (\ frac (T) (T_ (\ text (C)))) \ right) \ right) ~ (\ text (mN / m)),) </Dd> </Dl>

What is the formula for finding surface tension