Ultrasound is now widely known and applied in many fields. The rise of ultrasound has brought many conveniences to people, and their lives have been closely linked to ultrasound. Imagine what changes would occur in the human world if humans lost ultrasound.

Ultrasound, English for ultrasound. As the name suggests, it is a sound wave with a frequency exceeding the highest threshold audible to the human ear (20kHz). The frequency of sound waves that can be heard by the human ear is between 20Hz and 20kHz. Sound waves below 20Hz are called infrasound waves. Ultrasonic waves have good directionality, strong reflection ability, and are easy to obtain concentrated sound energy. They propagate farther in water than in air and can travel several meters in metal. Can be used for distance measurement, speed measurement, cleaning, welding, crushing, sterilization and disinfection, etc. There are many applications in medicine, military, industry, and agriculture.

Reverse radar: When reversing, using the principle of ultrasonic waves, the probe (transducer) installed on the rear bumper of the vehicle sends ultrasonic waves, which reflect off obstacles to form echoes. After receiving the echoes, the probe calculates the actual distance between the vehicle and the obstacle.

Transducers are important components in sonar (SONAR), which are devices that convert sound energy into mechanical energy, electrical energy, magnetic energy, etc. There are two uses: one is to emit sound waves underwater, called a "transmitting transducer", which is equivalent to a loudspeaker in the air (commonly known as a "microphone"); The second is to receive sound waves underwater, called a "receiving transducer", which is equivalent to a microphone (commonly known as an "earpiece") in the air. Transducers are often used to emit and receive sound waves simultaneously in practical use, and transducers specifically designed to receive sound waves are also known as "hydrophones".

There are many applications of ultrasound, far beyond the two mentioned in the article. If humans lose ultrasound, the first thing they can think of is reversing and returning to the era of primitive "looking at the rearview mirror". For some drivers, it will be a "nightmare". The ocean is mysterious and powerful, and ultrasound helps humans explore it. Without it, perhaps humans would not be able to explore deeper into the ocean and understand its secrets!