DESIGN OF DEMOSTRATION INSTRUMENT OF SOUND WAVE REFRACTION

The propagation of sound waves is a common issue in physics research. "Seeing is believing, but hearing is deceiving." With the help of modern schlieren display technology, sound waves can be visualized to demonstrate the refraction of sound and verify the laws of refraction. In the experiment, a Fresnel acoustic lens is installed in front of the ultrasonic probe to transform spherical waves into plane waves. A transparent gas box is filled with carbon dioxide to create a refractive interface with the air outside the box. Standing waves are used to enhance the path of sound refraction. The refracted wavefronts after the emission of spherical waves are not "concentric circular surfaces, " which is also analyzed. To demonstrate total reflection of sound waves, a water-saltwater liquid interface is designed. All these help students understand the propagation of sound waves and Huygens' principle.