Text 1 The Scientist and the Sensitive Snake 

Text 2 Buried Treasure 

Text 3 Man in a Hostile Land 

Text 4 Organized Crime 

Text 5 Oh, To Be a Steamboat Man 

Text 6 We’ll Never Conquer Space 

Text 7 The Bridge at Andau 

Text 8 Needed: An International Language 

Text 9 What Happens to Child Prodigies? 

Text 10 Most Popular Characters 

Text 11 Twins, Genes, and Environment 

Text 12 Why Are You Laughing? 

Text 13 The Awakening of a Continent 

Text 14 Why I Love Wisconsin 

Text 15 The Etruscan Enigma 

KEYS TO THE EXERCISES

Text 1  The Scientist and the Sensitive Snake

By Gerald Leach

1.In the dark night of the desert a group of U.S.Air Force scientists is testing a new device for guiding a missile to its target.Designed to seek out the heat of an enemy aircraft engine, it is now going through its paces by tracing the movement of a flashlight waving thirty feet away in the darkness.

2.A hundred yards away, unseen by the men, an equally deadly missile is searching out its prey.Sliding between the stones of the desert, a rattlesnake senses a patch of warmth.Without a sound the snake closes in and strikes for the kill.

3.Those two incidents dramatize one of the newest and most fascinating investigations of modern science.For the simple fact is that the missiles heat seeker, with its few thousand pounds of electronic gadgets, is huge and clumsy compared to the snake's.Although the snake's mechanism is small enough to be packed into a head the size of a walnut, it can detect a change in temperature of one-thousandth of a degree.The men working on the missile finder would dearly love to know how, for no man-made device can equal this.

4.Wherever we look in the animal world we find the same story.Almost anything that man can do, nature has already done better (and in far, far less space).Compare the camera and the eye, the computer and the living brain, the radar set and the bat's echo system.Man can only gasp in awe—and console himself with the fact that whereas he has been at it for a mere thousand years, nature has been perfecting its living gadgets for two thousand million years.

5.It is for the purpose of learning from nature that a new science has grown up.Called bionics, it is a kind of marriage between biology and electronics.Its aim is to find out how animals’ apparatus work so that man can copy them for his own use.

6.In some of the older branches of science, the name bionics raises half-smiles and scorn.Perhaps it does seem strange for a modern scientist to study scorpions, toads, blind fish, or spiders.To some, this may sound more like medieval magic than modern science.The list extends to bats, beetles, electric fishes and eels, waltzing mice, ants, locusts, lizards, and a host of others.However, when you look at the things this weird menagerie of creatures can do, the importance of bionics suddenly hits you.

7.Imagine being able to know a friend several miles off by his smell.Male silk moths can do this.Their antennae are so sensitive to the subtle chemical odor of female moths that they can detect their presence by picking up only one molecule of the chemical.Even with their most sensitive apparatus, human chemists cannot approach this perfection.

8.The high-pitched squeak that bats use for navigation is fairly well known.A bat can dart about in a room filled with crisscrossing wires without ever hitting one.This idea has already been copied in a navigation aid for the blind that utilizes sound.Even more delicate than the ear of a bat is the tiny ear of a kind of moth that bats prey on.This moth's ear is tuned in to the bat's ultrasonic squeak so that the moth can escape when it hears a bat in the area.Scientists have attached electrodes to the nerves of the moth's ear in order to produce a half living, half man-made microphone that possesses an unmatched sensitivity.

9.Dolphins and porpoises also navigate by some kind of echo system, and it is almost certain that these animals communicate in some way by sound.By swinging their heads from side to side, for instance, and letting out a series of ultrasonic blips, dolphins can “see” through twenty feet of muddy water and tell if a fish is good for eating.The U.S.Navy, whose own sound-locating apparatus is far less talented, would give a great deal to learn how the dolphin does this.

10.Studying beetles’ eyes has already paid off.A group of scientists in Germany found that a beetle can accurately measure with its eyes the speed of a moving background.After finding out how a beetle accomplishes this, the scientists built a machine that operated on the same principle.This instrument is able to determine the ground speed of moving aircraft with a high degree of accuracy.

11.Perhaps the most remarkable devices, and certainly the most sensitive, belong to the strange family of electric eels and fishes.In the muddy waters of South American rivers these fishes’ eyes are of little use to them.Instead of eyes they use extremely accurate electric sense organs.These fishes send a series of blips of electricity into the water around them.By noting how the pattern of electricity in the water changes, they can not only find their way about, but even detect very small objects in the water.They “see” through the use of electrical impulses.This fact can be demonstrated by rubbing a comb through one's hair (to create static electricity) and placing it by an electric fish's tank.The fish will go wild trying to find out what's going on.

12.Electric fish can tell the difference between two glass rods put into their tank inside a porous pot, even though one rod may be as little as a tenth of an inch thicker than the other.In technical terms, this means that they can detect a change in the electric field around them as low as three thousandths of a millionth of a volt per millimeter.In human terms, this would be like being able to tell the difference in the weight of a car made by a tiny fleck of dust settling on its roof.

13.The list of marvelous animal devices is endless.There is the snail with its built-in compass, the bee that navigates by polarized light, the fly that controls its flight by its back wings, which have become a delicate vibrating gyroscope.Man is now trying to copy all of these.Every child is familiar with the ability of birds to cross whole continents and oceans during their migrations.How do they do it—by following some kind of built-in compass, by making use of polarized light, by steering a course by the sun and stars? We do not know, but science has every hope of finding out.