According to the use the ultrasound can be divided into two groups: Active ultrasound, when applied exhibits physical or chemical effects. The generated output reaches higher values. The ultrasound is used for cleaning, welding, drilling and the like. Passive ultrasound output is contrast generated at much lower (usually small) values. His main area of application is then measuring distance, detecting defects in materials and thickness of the materials, measuring the flow of liquids and gases and also diagnostics in healthcare. Speed of sound is dependent on the type of environment in which it moves, and the current temperature of the environment. Velocity of sound in some materials is showed in Table 1