ARDMS Sonography Principles and Instrumentation (SPI) Practice Exam

In the context of acoustic physics, compressibility refers to the ability of a medium to change its volume under pressure. When compressibility increases, it means that the medium can be compressed more easily. This characteristic has a direct impact on how sound waves travel through that medium.

Acoustic velocity, or the speed at which sound travels through a medium, is primarily influenced by both the medium's density and its elasticity (or stiffness). An increase in compressibility leads to a decrease in the medium's stiffness. This decreased stiffness, in turn, requires sound waves to take longer to propagate through the medium, resulting in a reduction in acoustic velocity.

Therefore, as compressibility increases, the acoustic velocity decreases due to the reduced ability of the medium to resist deformation, slowing down the propagation of sound waves. This relationship helps in understanding how different materials will transmit sound differently, which is crucial in diagnostic imaging and other applications of sonography.