A concept of the turbidimetric method for determining the concentration of ethanol in water-ethanol mixtures is described. A closed sample cell containing the analyte was heated to achieve vapor saturation and subsequent condensation. As the condensation occurred, the decrease in percentage transmittance with time due to light scattering was measured at 540 nm. Measurements of a single sample were performed for a period of 300 s. The rate of decrease of percentage transmittance versus the concentration of water-ethanol standard solutions was used to generate a calibration curve. The technique demonstrates the use of light scattering for analytical applications and provides an opportunity to teach basic nucleation concepts.