Rajapintajännityksellä

Rajapintajännityksellä refers to the phenomenon of surface tension, a characteristic property of liquids. It describes the tendency of liquid surfaces to shrink into the minimum surface area possible. This effect arises from the cohesive nature of liquid molecules, which are attracted to each other. At the surface of a liquid, molecules are pulled inwards by their neighbors, creating a net inward force. This force causes the surface to behave like a stretched elastic membrane, resisting any external force that attempts to increase its area.

The magnitude of surface tension is measured as the force per unit length acting perpendicular to a line drawn on the liquid surface, or equivalently, as the energy required to increase the surface area by a unit amount. This property is responsible for various everyday occurrences, such as the formation of spherical droplets, the ability of insects to walk on water, and the capillary action that allows liquids to rise in narrow tubes. The temperature of the liquid also influences surface tension; it generally decreases as temperature increases because the increased thermal motion weakens the intermolecular forces. Impurities or dissolved substances can also alter the surface tension of a liquid.