英语听力—环球英语 1333 Hearing Mysterious Infrasound

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　　Welcome to Spotlight 1. I’m Liz Waid.
 
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　　And I’m Ryan Geertsma. Spotlight uses a special English method of broadcasting. It is easier for people to understand - no matter where in the world they live.
 
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　　What can this music do to your spirit?
 
　　The sound of an organ. The organ is probably the largest of all musical instruments. For 500 years churches in Europe have used organs. They have a pump and a number of pipes of different sizes. The pump blows air through the pipes. The pipes make the sounds. The musician sends the air to different pipes using a keyboard.
 
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　　We can hear most of the sound that an organ makes. But we cannot hear all of it. And a team of British scientists have said that the hidden part of church music has a strange effect on us. Today’s Spotlight is on this hidden sound: infrasound.
 
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　　Some sounds, or musical notes, are so low that we cannot hear them with our ears. There are high sounds and low sounds. This is the frequency 2 of the sound. Frequency is not volume - it is not loud or quiet. These very low frequency sounds are called infrasounds. The word has two parts. The first part comes from the Latin 3 word infra, meaning below. The second part is sounds - the things that you hear. An infrasound is lower in frequency than the usual sounds that our ears can hear.
 
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　　Sounds that our ears cannot hear are real enough. They can be very loud. They can travel a great distance. But you will not be hearing infrasound now, because your radio or computer cannot make the sounds. It would be different if you were in the church standing 4 near the organ. Then the infrasound would be all around you. You would not hear it with your ears. But you would feel it in your body. Your body would vibrate 5 - it would move slightly. You would feel the vibrations 6 in your chest especially. Infrasounds are real sounds, even though the human ear cannot hear them.
 
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　　Scientists in England did an experiment with infrasound. They tested the idea that infrasound can produce emotional 7 or spiritual feelings. They built a machine that makes a very low frequency sound. They hid the machine in a building in London that is used for musical performances. The building was the Purcell Room. After a performance the scientists asked the people in the Purcell Room some questions. They found that emotional and spiritual feelings increased by 22 percent when the infrasound machine was on. This is strong evidence that the low frequency sound is affecting people. A scientist from the University of Hertfordshire, Professor Richard Wiseman, was involved in the research. He told the BBC,
 
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　　“Some of the experiences of the people listening to infrasound included ‘shaking in the wrists’ ‘a strange feeling in the stomach’, ‘increased heart rate’, ‘feeling very worried’, and ‘a sudden memory of some sad event’.
 
　　This experiment was done under controlled conditions. It shows infrasound does have an effect. This may explain some of the unusual experiences people may be having in churches.”
 
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　　These strange effects appear in other places where there is infrasound. Machines that can make infrasound include airplanes, fast moving cars, and air-cooling devices 8. Such sounds may make people feel sick. Sometimes they cause pains in the head or a loss of balance.
 
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　　Scientists can also use infrasound to measure distant events. For example, earthquakes make infrasound. These sounds travel a very long way. Scientists can listen to these sounds from thousands of kilometres away. Nuclear bomb explosions 9 also create infrasound. This is how nuclear weapons are controlled. One country can hear the nuclear tests carried out by another. Infrasound means that no nuclear bomb can ever be tested in secret.
 
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　　There is a theory that birds use infrasound to know where they are. Some kinds of bird fly for thousands of kilometres each year. They are looking for food and a place to lay eggs. The birds travel by using landmarks 10 such as rivers, islands and coasts. But they may also use infrasound waves created by the wind and weather. This would help them to avoid bad weather. It is difficult to test this theory. Birds have wonderful skills for finding 11 their way around the world. Infrasound is probably only one of several methods they use.
 
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　　Another creature using infrasound is the elephant - the world’s largest land animal. The biologist Katy Payne studies the way that elephants use infrasound. She wrote a book about African elephants called Silent Thunder. The book shows that elephants can find members of their family over long distances by using infrasound. One elephant can signal to another three kilometres away.
 
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　　The interesting part is the way Katy Payne discovered this infrasound. One day, she was close to two elephants. The elephants were communicating with deep rumbling 12 sounds. Payne felt these sounds more than she heard them. It reminded her of being in a church as a child. It reminded her of what she felt when the church organ was playing its lowest notes. It was more about feelings than knowledge. Later she was able to use scientific instruments to prove that the infrasounds were real. She could not hear them through her ears, but the instruments could measure them. Later, she began a project to record these sounds. She is trying to understand more about elephant communication.
 
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　　Infrasound shows us that there are things in nature that we cannot hear or see. Our ears and eyes do not tell the whole story. Few of us would have been able to feel the sounds made by the elephants. Few of us would have made any sense of the feelings caused by the church organ, or airplanes. These things help us to remember that what we can see and hear is not all that there is!
 
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　　Have you felt infrasound where you live? What caused it? Leave your comments on the script 13 page for this program.
 
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　　The writer of this program was Peter Laverock. The producer was Luke Haley. The voices you heard were from the United Kingdom and the United States. All quotes were adapted for this program and voiced by Spotlight. You can listen to this program again, and read it, on the internet at http://www.radio.english.net This .program is called, ‘Hearing Mysterious Infrasound’.
 
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　　You can also leave your comments on our website. Or you can email us at radio@radioenglish.net. You can also find us on Facebook - just search for spotlightradio. We hope you can join us again for the next Spotlight program. Goodbye.