Sound waves are mechanical vibrations that travel through a medium such as solids, liquids, or gases, carrying energy as oscillations of pressure and particle displacement. Sound waves exist in a wide range of frequencies. For humans, the audible range is 20 Hz (cycles per second) up to 20 kHz. Many animals are sensitive to other frequency ranges. Elephants are sensitive to infrasound, those vibrations below 20 Hz, while bat sensitivity extends to 200 kHz. The Greater Wax Moth detects the vibrations up to 300 kHz, helping it avoid the predatory bats. Hearing any of the mechanical frequencies requires a transducer capable of mechanically converting sound...
