Musical instrument refers to an instrument that can play timbre and melody in various ways. Musical instruments are divided into four categories: wind instruments, stringed instruments, percussion instruments and other instruments. Different musical instruments vibrate in different parts. When playing clarinet, the air in the flute will vibrate.
Sound is the sound wave produced by the vibration of an object. It is a wave phenomenon, which propagates through media (air or solid or liquid) and can be perceived by human or animal hearing organs. The source of the object sound that vibrates (vibrates) at first. Sound vibrates in waves. Sound is the movement formed by sound waves propagating through any medium.
Sound is a wave. Sound that can be recognized by human ears (the frequency is between 20Hz and 20000Hz) is called sound. The propagation speed of sound in different media is generally solid >: liquid > gas (except cork, etc.) 500m/s, less than kerosene (25℃), distilled water (25℃), etc. ), and the speed of sound propagation is related to the type and temperature of the medium.
Application of ultrasound in acoustics;
1. Stones in the human body can also be crushed by the huge energy of ultrasonic waves.
Cleaning metal parts, glass and ceramic products is very troublesome. If ultrasonic waves are introduced into the cleaning liquid containing these articles, the violent vibration of the cleaning liquid will impact the dirt on the articles, and it can be cleaned quickly.
3. Ultrasonic detection of metal, ceramic concrete products and even reservoir dams to check whether there are bubbles, cavities and cracks inside.
4. The surfaces of various internal organs of human body have different reflection abilities to ultrasonic waves, and the reflection abilities of healthy internal organs and sick internal organs are also different. The so-called "B-ultrasound" is to compare the ultrasonic waves reflected by internal organs to help doctors analyze the lesions in the body.