kosketuskulmaa

Kosketuskulmaa is the partitive form of kosketuskulma, a Finnish term used in science to refer to the contact angle. The underlying concept is the angle at which a liquid interface meets a solid surface, a measure that reflects how well a liquid wets a solid. In Finnish-language literature, kosketuskulma (and its inflected forms such as kosketuskulmaa) is the standard term for this property, which is central to studies of wettability and interfacial phenomena.

In practical terms, the kosketuskulma (contact angle) is defined at the line where the liquid, solid, and air meet. It can be measured staticly, using a drop of liquid on a solid and observing the drop profile, or dynamically, where advancing and receding contact angles describe how the angle changes with liquid motion. The measurement is often carried out with a goniometer or similar imaging setup, and the value provides information about surface energy and adhesion.

Theoretically, the contact angle is linked to surface tensions through Young’s equation, which relates the solid–vapor, solid–liquid, and liquid–vapor interfacial tensions to the observed angle. Values below about 90 degrees indicate good wetting (hydrophilic behavior in water-based systems), while values above 90 degrees indicate poor wetting (hydrophobic behavior). Dynamic aspects of kosketuskulma, including hysteresis between advancing and receding angles, reveal surface roughness and chemical heterogeneity.

Applications of kosketuskulmaa span coating technologies, inkjet printing, microfluidics, biology, and soil science, wherever control of liquid spreading on solids is important. See also wettability, goniometry, and interfacial science.