Since frosting to a cooling surface has often caused the loss of equipment performance, it is important to investigate the method for efficient removal of frost crystals from the cooling surface. Thus, authors focus on frosting from generation to the primary stage of growth because the scraping force of frost crystals on the cooling surface until the primary stage is expected to be weak. However, considering the dimensions of frost crystals until the primary stage, it is essential to measure frost crystals dimensions/distribution and scraping force in micro scale field. In this paper, using a scanning probe microscope (SPM), dimensions/distribution and scraping force of forest crystals until the primary stage were measured by authors' proposed method, varying humidites. And then, the correlations among them were clarified, comparing influences of the humidity with those of the surface temperature.
