99 Seeing Sound-Mid

Seeing Sound FOCUS Question What would different sounds look like if people could see them?

如果人们能看到不同的声音，它们会是什么样子?

What's That Sound? Tap a spoon against a glass of water. Small particles, called molecules, in the glass vibrate. The vibrating molecules touch other molecules of water and air. This makes them vibrate, too. The vibrations go in all directions. Some of the vibrations travel into people's ears and vibrate their eardrums. The ears send signals to the brain. That's how people hear the sound clink! Sound is a vibration that travels through matter and can be heard. But what would sound look like if people could see it?

那是什么声音?用勺子轻敲一杯水。 玻璃中的小颗粒，即分子，会振动。 振动的分子接触到水和空气的其他分子。 这也会使它们震动。 振动向各个方向传播。 一些振动进入人们的耳朵，振动他们的耳膜。 耳朵向大脑发送信号。 人们就是这样听到叮当声的!声音是一种在物质中传播的振动，可以被听到。 但如果人们能看到它，声音会是什么样子呢?

How We See Sound Hold a rubber band sideways between your thumb and finger. Then pluck it with another finger. The rubber band vibrates. Each time the rubber band moves up, nearby air molecules are compressed, or squeezed together. Each time the rubber band goes down, those same air molecules spread out. This motion happens over and over. These vibrations create a sound wave. You might hear a boing! People can't see sound waves moving through the air like they can see waves in the ocean. But we can use technology to measure how tall each sound wave gets and how far apart the waves are. Then, by graphing the results people can "see" the sound.

用拇指和其他手指夹住一根橡皮筋。 然后用另一个手指拔它。 橡皮筋振动。每次橡皮筋向上移动时，附近的空气分子就会被压缩或挤在一起。 每次橡皮筋向下，这些相同的空气分子就会散开。 这个动作反复发生。 这些振动产生了声波。 你可能会听到一声巨响!人们不能像看到海洋中的波浪一样看到声波在空气中移动。 但我们可以利用技术来测量每个声波的高度以及波之间的距离。 然后，通过绘制结果，人们可以“看到”声音。

What Sound Looks Like People use special equipment that turns sound waves into a graph of wavy lines called a waveform. The waveform shows the shape of sound waves. The top point of the wave is called the crest and the bottom point is called the trough (rhymes with "off"). A waveform has many crests and troughs. Sounds can be quiet, like a fluttering leaf, or loud, like a clanging bell. They can be low like a growling bear, or high, like a squeaking mouse. Since sounds are different each waveform looks different.

声音的样子人们使用特殊的设备将声波转换成波形。 波形显示声波的形状。 波浪的顶部点称为波峰，底部点称为波谷(与“off”押韵)。 波形有许多波峰和波谷。 声音可以是安静的，像树叶飘动，也可以是响亮的，像叮当作响的铃铛。 它们可以低得像咆哮的熊，也可以高得像尖叫的老鼠。 因为声音是不同的，每个波形看起来都不一样。

Get Amped About Amplitude Loud sounds, like blasting music, have a lot of energy. Many people can hear and even feel the vibrations. Turn the radio down, and there is less energy. Amplitude is the height of a sound wave from the top of the crest to the bottom of the trough. It describes the amount of energy in a sound. Loud sounds have high amplitude, so the waves look tall. Quiet sounds have low amplitude, so the waves look shorter. Word Wise You can amplify sound using an electric amplifier, or amp. This increases the volume of the sound and the amplitude of the sound waves.

大声的声音，比如爆炸的音乐，有很多能量。 很多人都能听到甚至感觉到震动。 把收音机的声音调小，能量就会减少。 振幅是声波从波峰顶部到波谷底部的高度。 它描述了声音中所含的能量。 响亮的声音振幅很高，所以声波看起来很高。 安静的声音振幅较低，所以声波看起来较短。 你可以使用电放大器(amp)来放大声音。 这增加了声音的音量和声波的振幅。

Pitch-Perfect Frequency Frequency measures the speed of a vibration. It counts the number of waves that pass a point in one second. We measure frequency in units called hertz (Hz). People hear the frequency of sound waves as pitch, or whether a sound is high or low. Slow vibrations produce waves that are farther apart, with low frequency. The sound has a low pitch. Fast vibrations produce waves with high frequency. The sound has a high pitch. Both low- and high-frequency sound waves move fast. For example, human speech makes sounds with waves that move between 100 and 16,000 hertz. Do You Know? Sounds that have random frequencies are called noise. These waveforms look jagged.

完美音调频率频率测量振动的速度。 它计算一秒钟内通过一个点的波数。 我们以赫兹(Hz)为单位来测量频率。 人们听到声波的频率是音调，或者声音是高还是低。 慢振动产生的波间隔较远，频率较低。 这个声音音调很低。 快速振动产生高频波。 这个声音音调很高。 低频声波和高频声波都传播得很快。 例如，人类说话时发出的波在100到16000赫兹之间移动。 你知道吗?具有随机频率的声音称为噪声。 这些波形看起来参差不齐。