04 Electricity
The modern age is an age of electricity. People are so used to electric lights, radio, televisions, and telephones that it is hard to imagine what life would be like without them. When there is a power failure, people grope about in flickering candlelight, cars hesitate in the streets because there are no traffic lights to guide them, and food spoils in silent refrigerators.
Yet, people began to understand how electricity works only a little more than two centuries ago. Nature has apparently been experimenting in this field for million of years. Scientists are discovering more and more that the living world may hold many interesting secrets of electricity that could benefit humanity.
All living cell send out tiny pulses of electricity. As the heart beats, it sends out pulses of record; they form an electrocardiogram, which a doctor can study to determine how well the heart is working. The brain, too, sends out brain waves of electricity, which can be recorded in an electroencephalogram. The electric currents generated by most living cells are extremely small often so small that sensitive instruments are needed to record them. But in some animals, cert 04 Electricity
The modern age is an age of electricity. People are so used to electric lights, radio, televisions, and telephones that it is hard to imagine what life would be like without them. When there is a power failure, people grope about in flickering candlelight, cars hesitate in the streets because there are no traffic lights to guide them, and food spoils in silent refrigerators.
Yet, people began to understand how electricity works only a little more than two centuries ago. Nature has apparently been experimenting in this field for million of years. Scientists are discovering more and more that the living world may hold many interesting secrets of electricity that could benefit humanity.
All living cell send out tiny pulses of electricity. As the heart beats, it sends out pulses of record; they form an electrocardiogram, which a doctor can study to determine how well the heart is working. The brain, too, sends out brain waves of electricity, which can be recorded in an electroencephalogram. The electric currents generated by most living cells are extremely small often so small that sensitive instruments are needed to record them. But in some animals, certain muscle cells have become so specialized as electrical generators that they do not work as muscle cells at all. When large numbers of these cell are linked together, the effects can be astonishing.
The electric eel is an amazing storage battery. It can seed a jolt of as much as eight hundred volts of electricity through the water in which it live. As many as four-fifths of all the cells in the electric eels body are specialized for generating electricity, and the strength of the shock it can deliver corresponds roughly to length of its body.
ain muscle cells have become so specialized as electrical generators that they do not work as muscle cells at all. When large numbers of these cell are linked together, the effects can be astonishing.
The electric eel is an amazing storage battery. It can seed a jolt of as much as eight hundred volts of electricity through the water in which it live. As many as four-fifths of all the cells in the electric eels body are specialized for generating electricity, and the strength of the shock it can deliver corresponds roughly to length of its body.
2017届高考英语一轮总复习精选单元练习人教版必修2《Unit 4 Wildlife protection》
2017届高考英语一轮总复习单元测试(十七)
2017届高考英语二轮热点复习专题训练:语法单选题系列20
2017届高考英语二轮热点复习专题训练:语法单选题系列2
2017届高考英语二轮热点复习专题训练:语法单选题系列1
2017届高考英语二轮热点复习专题训练:语法单选题系列26
2017届高考英语一轮总复习单元测试(十九)
2017届高考英语二轮热点复习专题训练:语法单选题系列25
2017届高考英语一轮总复习单元测试(十四)
2017届高考英语一轮总复习精选单元练习人教版必修5《Unit 3 Life in the future》
2017届高考英语二轮热点复习专题训练:语法单选题系列16
2017届高考英语二轮热点复习专题训练:语法单选题系列13
2017届高考英语一轮总复习精选单元练习人教版必修1《Unit 2 English around the world》
2017届高考英语二轮热点复习专题训练:语法单选题系列21
2017届高考英语一轮总复习精选单元练习人教版选修6《Unit 2 Poems》
2017届高考英语一轮总复习单元测试(十三)
2017届高考英语一轮总复习精选单元练习人教版必修2《Unit 5 Music》
2017届高考英语二轮热点复习专题训练:语法单选题系列15
2017届高考英语一轮总复习精选单元练习人教版必修3《Unit 5 Canada—“The True North”》
2017届高考英语二轮热点复习专题训练:语法单选题系列18
2017届高考英语一轮总复习精选单元练习人教版必修4《Unit 5 Theme parks》
2017届高考英语一轮总复习精选单元练习人教版必修2《Unit 3 Computers》
2017届高考英语二轮热点复习专题训练:语法单选题系列24
2017届高考英语一轮总复习精选单元练习人教版必修4《Unit 2 Working the land》
2017届高考英语一轮总复习精选单元练习人教版必修3《Unit 1 Festivals around the world》
2017届高考英语一轮总复习单元测试(十一)
2017届高考英语二轮热点复习专题训练:语法单选题系列19
2017届高考英语一轮总复习精选单元练习人教版必修1《Unit 5 Nelson Mandela –a modern hero》
2017届高考英语一轮总复习精选单元练习人教版必修1《Unit 1 Friendship》
2017届高考英语一轮总复习精选单元练习人教版必修4《Unit 1 Women of achievement》
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