In order to simulate scaling phenomena we have developed an experimental procedure which is based oil the analysis of a laser beam reflected by the surface of an electrode where calcium carbonate crystallization takes place. Experiments were carried out with natural waters on copper and steel electrodes. Interpretation of the results was made using an atomistic model proposed by Beaunier et al. Two types of crystallization were distinguished: . The progressive nucleation when the number of crystals (nuclei) increases with time and the growth of the crystals takes place simultaneously. . The instantaneous nucleation followed by the growth of a constant in a number of crystals. Using the model, the crystallization phenomena were quantified by the nucleation rate and the product of the lateral growth constant and the density of sites. Moreover, the experiments showed that the nature of the substrate influences the nucleation step but that the growth step depends only on the bulk concentration of calcium carbonate. (C) 2004 Elsevier B.V. All rights reserved.