There are many uses for sound in the world today. We have already mentioned a few. Musicians can benefit from a greater understanding of sound, architects must understand sound to design effective auditoriums, detectives can use sound to identify people and many new types of technology apply sound recognition.
Nondestructive testing is a method of finding defects in an object without harming the object.
Often finding these defects is a very important task. In the aircraft industry, NDT is used to look for internal changes or signs of wear on airplanes. Discovering defects will increase the safety of the passengers. The railroad industry also uses nondestructive testing to examine railway rails for signs of damage. Internally cracked rails could fracture and derail a train carrying wheat, coal, or even people.