ABSTRACT
Real liquids have some elasticity of shape. Such elasticity is significant only at very high deformation rates, greatly exceeding the velocity of ultrasonic waves at the highest frequencies with which they can propagate in the liquid without significant attenuation. Due to the absence of shear stresses in an ideal liquid, the stresses existing in it always act perpendicular to any surface area singled out in the liquid, and the force of the pressure applied to the volume element passes through its center of mass, producing only translational motion of the particles. The velocity of sound in a liquid cannot be calculated with the same accuracy because a satisfactory model, which would enable the calculation of the magnitude of the bulk modulus theoretically, does not exist for liquids. In contrast to gases, the velocity of sound in almost all liquids decreases monotonically and quite considerably with temperature.
