第五篇The Magic〔魔法〕 of Sound Music is one of the most beautiful forms of artistic expressions ever invented. In movies and plays , music has an added function: it not only moves people but also can shock〔震惊〕people. Is it true that an ordinary musical instrument can be so powerful? Our eardrums〔耳膜〕can withstand〔承受〕sound within 20 to 80 decibels. Once sound exceeds〔超过〕this limit,even beautiful music will become ear-splitting〔分类〕noise and harm health. A strong blast〔爆炸〕of high sound can twist〔扭〕 and break a solid iron sheet. High sound of l50 decibels〔分贝〕can kill a healthy rat. The noise from a plane's engine is over l40 decibels. However, the sound of a flute〔长笛〕is at most a few decibels. Therefore,the sound of ordinary musical instruments cannot harm your health.It has been proven that people who have worked in an environment with a high sound intensity for a long time suffer varying〔变化〕degrees of heart disease or altered〔改变〕brain waves. In movies , sometimes the hero can produce a sound that ordinary people can't hear and only those who have the same ability can feel. In nature , there is actually〔确实〕sound that is beyond〔超过〕our hearing. In physics, the sound that exceeds〔超过〕20 ,000 Hz is called ultrasonic〔超声波〕. Dolphins〔海豚〕, whales〔鲸〕and bats〔蝙蝠〕can make such high-frequency〔频率〕sound. It does no harm to health. Sound less than 20 Hz is called infrasonic waves. When we move , the air will vibrate（振动）. The vibration〔振动〕of air can produce infrasonic〔次声的〕waves.As the frequency（频率）of infrasonic waves is close to that of people's internal(国内的、体内的) organ（器官），infrasonic wave may cause resonance（共鸣）in human bodies. As a result, people's vision（视力）may weaken（削弱）and intemal organs may rupture（破裂）. However, whether an infrasonic wave can be used as a weapon（武器）depends on its intensity（强度）. lf its intensity is verylow , it won’t damage intemal organs or a person's health. If the intensity〔强度〕of infrasonic wave exceeds〔超过〕l60 decibels , it is extremely〔非常的〕harmful.When wind blows at a force of 3 or 4 over the sea , it will produce infrasonic waves of several decibels. Only typhoons（台风）can produce infrasonic waves of over l00 decibels. At present, scientists can only produce infrasonic weapons in the lab with the help of advanced scientific tools and powerful electric power. 练习: A High sound of l50 decibels〔分贝〕can kill a healthy rat. B The vibration〔振动〕of air can produce infrasonic〔次声的〕waves. C We cannot play high-pitched〔声调高的〕music with ordinary musical instruments〔乐器、仪器〕. D If the intensity〔强度〕of infrasonic wave exceeds〔超过〕l60 decibels , it is extremely〔非常的〕harmful. E Dolphins〔海豚〕, whales〔鲸〕and bats〔蝙蝠〕can make such high-frequency〔频率〕sound. F Therefore,the sound of ordinary musical instruments cannot harm your health. 第五篇奇妙的声音 音乐是最美妙的艺术表达形式。在电影或是戏剧中，音乐有一种另加的功能，不仅能感动人也能使人震撼。一件普通的乐器真的能这样有魔力吗? 我们的耳膜能够接收20-80分贝的声音。一且超越了这个界限，再美的音乐也只是震耳的噪声，还会危害健康。一阵高分贝的强烈的冲击波能使一块铁板扭曲和破裂。高达150分贝的声音能杀死一只健康的老鼠。 飞机引擎发出的噪声超过了140分贝。而长笛发出的声音最多只有几个分贝。所以，一件普通乐器发出的声音不会危害你的健康。 在电影里，有时主角能发出常人无法听到的声音，只有具有相同能力的人才能够感觉到。在自然中，确实有一种声音在我们的听力之外。物理学中，超过20000赫兹的声音称之为超声波。海豚、鲸鱼和蝙蝠能发出这样高频的声音。这些对我们的健康无害。 低于20赫兹的声音称之为次声波。当我们移动时，空气会振动，空气的振动会产生次声波。由于次声披的频率接近于人体内部器官的频率，它能够引起人体的共振。所以，人的视力会下降，内部器官会破裂。但是，次声波能否用作武器取决于次声波的强度。如果次声波的强度低，不会伤害人的内部器官或影响人的健康。如果次声波的强度超过160分贝，就极为有害。当海面上吹起3-4级风的时候，会产生几种分贝的次声波。只有台风能够产生超过100分贝的次声波。现在，科学家只能在实验室中，通过先进的科学工具和强大的电力才能够制造次声波武器。 本文来源：https://www.wddqw.com/doc/1f274277376baf1ffd4fad3e.html