In order to determine physically justified relations between bubble characteristics and the physicochemical properties of liquid employed, bubble size distributions and average bubble diameters were calculated using theoretically justified model of gas bubbling through the liquid layer. The model of the gas bubbling enabling the calculations of the bubbles diameter has been based on the original approach by Prince and Blanch. It assumes an equilibrium between the coalescence and dispersion processes, and uses a simplified method of solution of the population balance equations. This model has been verified experimentally for different organic liquids (acetaldehyde, acetone, cyclohexane, isopropanol, methanol, n-heptane, toluene) and columns of different scale: glass laboratory column 9 cm diameter and 200 cm high, operated at atmospheric pressure and low temperature; stainless steel pilot plant column 30.4 cm diameter and 400 cm high, operated at elevated pressure (up to 1.1 MPa) and temperature (up to 160 degrees C). The model has been subsequently used to establish a theoretically based correlation for the bubble diameter by means of a numerical experiment using 'virtual liquids'.