95 Sound-High

Sound Written by Robert N. Knight

作者:Robert N。 骑士

What Is Sound? Can you describe what sound is? You might say that sound is something we hear with our ears. How does sound move from one place to another? How does sound get to your ears? How do your ears hear sound? This book will help you understand the answers to these and other questions about sound.

声音是什么?你能描述一下声音是什么吗? 你可能会说声音是我们用耳朵听到的声音。 声音是如何从一个地方传到另一个地方的? 声音是如何进入你的耳朵的? 你的耳朵是如何听到声音的? 这本书将帮助你理解这些和其他关于声音的问题的答案。

A thick blanket of air surrounds Earth. This air is made of tiny, invisible particles. Sound travels through the particles in air to your ears. But how does this happen? First of all, it's important to know that sound is a kind of energy. Like all energy, sound has the ability to move things and make things happen. Sound moves through air by making the tiny particles in air vibrate, or move back and forth. Think About It A jar full of air and a jar full of sand have something in common. They are both filled with particles. The jar full of air has many invisible air particles that you can't see.

一层厚厚的空气包围着地球。 这种空气是由微小的看不见的粒子组成的。 声音通过空气中的微粒传到你的耳朵。 但这是如何发生的呢?首先，知道声音是一种能量是很重要的。 像所有的能量一样，声音也能移动物体，使事情发生。 声音通过使空气中的微小颗粒振动或来回移动在空气中传播。 一个装满空气的罐子和一个装满沙子的罐子有一些共同之处。 它们都充满了粒子。 充满空气的罐子里有很多看不见的空气粒子。

Suppose you bang on a drum or hit a baseball with a bat. These actions cause the drum or the bat to vibrate. A vibrating drum or bat then makes the particles of air around it vibrate. The vibrations of one particle cause the particle next to it to vibrate. The vibrations spread out to other particles, causing the sound energy to move away from the object making the sound. Wowser! Sound moves a lot faster than most things on Earth. It moves through air near the ground at a speed of over 1,200 kilometers per hour (750 mph). It moves more slowly high above Earth, where there are fewer air particles.

假设你敲鼓或者用球棒打棒球。 这些动作导致鼓或球棒振动。 振动的鼓或球棒使它周围的空气粒子振动。 一个粒子的振动引起它旁边的粒子振动。 振动扩散到其他粒子，导致声音能量远离发出声音的物体。 老古板!声音的传播速度比地球上大多数东西都要快得多。 它在靠近地面的空气中以每小时1200公里(750英里/小时)的速度移动。 它在地球上空移动得更慢，那里的空气颗粒更少。

How Do Waves Travel? Sound energy travels through air as sound waves. They are like waves you see in the ocean. But sound waves are different from water waves. Water waves only travel across the surface of water, while sound waves travel out from a vibrating object in every direction. Every sound you hear comes to you as a sound wave.

波浪是如何传播的?声能以声波的形式在空气中传播。 它们就像你在海洋中看到的波浪。 但是声波不同于水波。 水波只在水面上传播，而声波从振动物体向各个方向传播。 你听到的每一个声音都是声波。

A sound wave has two parts. In one part, the particles of air are squeezed together, or compressed. In the other part, the air particles are spread out. Look at the sound waves below. Each compressed part of each wave is followed by a part where the particles are spread out. All sound waves have a regular pattern like the waves in the drawings. Different sounds make different wave patterns. But sound waves all have parts where particles of air are squeezed together and parts where they are spread out. Let's find out how waves made by soft and loud sounds are different.

声波有两部分。 在一个部分，空气颗粒被挤压在一起，或被压缩。 在另一部分，空气颗粒分散开来。 看看下面的声波。 每个波的每个压缩部分后面都有一个粒子散开的部分。 所有的声波都有一个规则的模式，就像图中的波一样。 不同的声音产生不同的声波模式。 但声波都有一部分是空气粒子被挤压在一起的，还有一部分是它们被扩散出去的。 让我们来看看柔和的声音和响亮的声音产生的波有什么不同。