The phenomenon of jellyfish receiving infrasound waves has given people great inspiration. Based on this principle, people successfully designed the “jellyfish ear storm predictor”. The bell-shaped radio horn of this instrument is equivalent to a jellyfish's hearing stone. It is installed on the deck of a ship or on the coast and is propelled by a small electric motor. It continues to rotate like a radar dish, searching for the direction in which the infrasound waves are arriving. When the speaker receives the "ocean sound", under the action of the instrument's feedback system, the speaker immediately stops rotating. Then, the resonator amplifies the infrasonic oscillation and then transmits it to the piezoelectric quartz chip. The infrasonic oscillation is converted into. current oscillation, amplified by an electronic amplifier, displayed on a fluorescent screen, or indicated by a microvoltmeter. This instrument isvery effective in forecasting storms and can accurately measure the duration and intensity of storms in advance. Currently, infrasound receivers are not very advanced and can only detect storms that are not too far from shore. They can't do anything further. But we believe that with the development of science and technology and the further exploration of nature, it will not be long before scientists will be able to use more advanced observation technology to predict any storm on the ocean. By then, people will actually be able to understand climate change in the oceans. Different jellyfish have different shapes and there are around 250 species worldwide. More than 95% of the body of jellyfish is made up of water and the rest is made up of proteins and lipids. Therefore, the body of jellyfish is transparent due to the water it contains.The umbrella body of ordinary jellyfish is not very large, only 20-30 cm long. Some jellyfish not only change color, but also glow in water. Some glow with a faint light green or blue-purple light, and some have a rainbow-like halo. When they swim in the sea, they turn into balls of dazzling colors. . Jellyfish's glow relies on a wonderful protein called equimin. When this protein is mixed with calcium ions, it emits a strong blue light. The greater the amount of equimin in the jellyfish, the stronger the light it emits. Each jellyfish contains an average of only 50 micrograms.
Ultrasound is a type of sound wave and sound wave is a mechanical wave, that is, a longitudinal wave generated by the vibration of a object. The number of vibrations per second. is called the frequency of the sound wave (the unit is Hertz: Hz).
Pictured aboveThe sound waves generated by the tuning forkcause vibrations on the water surface
Similar to the human eye can only see specific wavelengths (roughly (electromagnetic waves between 300 nanometers and 700 nanometers), the human ear can only hear sound waves whose frequencies vary from about 20 Hz to 20,000 Hz. Sound waves with frequencies above 20,000 Hz are called ultrasonic waves.
How was ultrasound discoveredHuman ears cannot hear ultrasonic waves, but some animals can. can. In 1794, Spallanzani discovered that bats navigated using inaudible sounds
In 1876, Galton invented the dog whistle, a special whistle that could emit a frequency of 20,000 Hz. 'at 50,000 Hz sound waves, this type of sound wave has exceeded the limit of human hearinge, but cats and dogs can hear it, because the upper limit of the dog's hearing range is about 40,000 Hz, and the upper limit of the cat's hearing range is about 60,000 Hz
Ultrasound was therefore discovered about more than 200 years ago, and truly applicable ultrasound was discovered by Marie Curie's husband, Pierre Curie, and his brother in 1880, when they. discovered the piezoelectric effect. Then, ultrasonic waves can be emitted. and detected based on the piezoelectric effect, thus opening the door to ultrasonic applications.
Characteristics of ultrasonic wavesBecause the wavelength is inversely proportional to the frequency, and the ultrasonic frequency is relatively high, the wavelength is short, which means that the ultrasonic wave has good directivity, and due to the short wavelength, high frequency and strong vibration, it has higher energys high.
Ultrasound also has good penetrability, so it can propagate long distances inside the material. Based on these characteristics, the application of ultrasound is also divided into two main areas.
Application fields of ultrasoundDue to its good directionality and strong penetration, there are two main application fields: detection and detection, such as B-ultrasound commonly used in medicine. Ultrasound It is an indispensable diagnostic method for clinical medicine to explore the internal structure of the human body based on the law of reflection with little damage to the human body.
There is also a sonar system, which uses ultrasonic waves and is widely used in navigation and aviation to detect upcoming obstacles. Besides, there are many similar apps like DetectsUltrasonic flaw testers specialized in surface production detection of precision parts.
The second area is ultrasound treatment, which is achieved using the powerful energy of ultrasonic waves. For example, ultrasonic cleaning of glasses, dust removal in factories, ultrasonic welding, etc. are all made by strong vibrations. ultrasonic waves.