全日制普通高中物理教科书(必修加选修)第二册(人教社2003年6月第1版)第63面指出:“超声波在水中传播的距离要比光波和无线电波远得多.”很多师生对此理解不够到位,本文予以探讨.自19世纪末列20世纪初,物理学发现了压电效应与反压电效应后,人们发明了利用电子技术产生超声波的办法,从此揭开了发展与推广超声技术的历史篇章.超声波是指频率在20 kHz 以上,不能引起正常人听觉 Section 63 of the Full-time Ordinary High School Physics Textbook (Compulsory and Optional), Volume 2, June 2003, states: “Ultrasound travels much farther in the water than light waves and radio waves.” Many teachers and students do not understand this enough place, this article will be explored.From the late 19th century early 20th century, physics found the piezoelectric effect and the anti-piezoelectric effect, people invented the use of electronic technology to produce ultrasound, from which The development and promotion of ultrasound in the history of the chapter.Ultrasonic refers to the frequency above 20 kHz, can not cause normal human auditory