Answer Key - Guide to Reading.pdf - Complete Guide - lulubulu

86 Section 1 Guide to Reading

because an area is officially protected, that doesn’t mean

that no one exploits the resources of that area. You can hire

people to guard these resources but they can be corrupted,

bribed. There’s a good market for the parts of some endan-

gered animals, for tropical hardwoods, for the artifacts of

ancient peoples. So you’ve got a lot of illegal hunting, of . . .

uh, cutting down trees, of stealing, and the roads just make

it easier to do this, to get there and to get those illegal

goods out.

And what about the local people who are supposed to

benefit so much from this influx of eco-tourist revenue? It’s

true; there are usually more jobs than before. But often the

local people have the most menial, the lowest-paying jobs

available. Not only that, many of the jobs are filled by peo-

ple from other areas who come there looking for work. And

then, there’s cultural pollution, which happens when an

isolated society suddenly comes in contact with Western

civilization. You have people who were poor farmers or

hunter-gatherers one day and the next, they’re talking on

cell-phones, they’re surfing the Internet. Societies are

changed, customs are lost.

So, once again, eco-tourism and in fact, all tourism has

its benefits, but it is not the perfect solution to development.

3. C The author says, “the American bison spread

throughout the open grasslands of North America,

but in the southern part of the continent there are

deserts, so the bison could not spread there.” We

can infer from this sentence that bison can live

only in open grasslands.

4. D The author says that “Most places that are suitable

for the growth of dandelions are already occupied

by other plants that are well adapted to the area.

The dandelion seedling must compete with these

plants for space, water, light, and nutrients. Facing

such stiff competition, the chances of survival are

slim.” Clearly, it is the competition with other

species of plants that causes so few dandelion

seedlings to survive.

5. B The author does give an example of A in paragraph

4 (the Kirkland’s warbler). There is an example of C

in paragraph 4 (the blue spotted salamander) and

of D in paragraph 5 (the Engelmann spruce).

However, there is no example of B, an aquatic ani-

mal that is stopped by physical barriers.

6. D In many cases, the word slim means “thin,” but in

this case it is used with the word chances to mean

“unlikely possibilities.”

7. D The two locations that the Kirkland’s warbler is

restricted to by behavioral borders are “a few

places in Michigan in the summer and . . . the

Bahamas in winter.”

8. C The author states, “Brazil’s Amazon River serves as

a northern or southern boundary for many species

of birds. They could freely fly over the river, but

they seldom do.” This indicates that the Amazon is

an example of a behavioral barrier rather than a

physical one.

9. A In paragraph 6, the author says, “The greatest dif-

ference between a corridor and a filter route is that

a corridor consists of one type of habitat, while a

filter consists of several similar types.”

10. A The New Zealand mud snail is an example of an

invasive species that was carried unintentionally

to its new environment. (“An example is the New

Zealand mud snail, which was accidentally

brought to North America . . .”)

11. B This choice best restates the original sentence.

Although this choice does not give the examples

mentioned in the original sentence (predators,

parasites, and competitors) and although it uses

different grammar and vocabulary, this choice is

closest in meaning to the sentence from the pas-

sage. Choice A leaves out some important infor-

mation from the original sentence, and choices C

and D are not accurate.

12. You should circle the second square. The word they in the

new sentence refers back to birds, and the sentence

explains why birds appear in places far from their homes.

The third type of natural pathway is called a

sweepstakes route. This is dispersal caused by the

chance combination of favorable conditions.

Narrator: Now get ready to answer the question. Remember,

you may turn the page and look back at the reading pas-

sage. You may also use your notes to help you. You have

twenty minutes to prepare and write your response.

Question: Summarize the main points made in the lec-

ture that you just heard, discussing how they cast doubt on

the main points of the reading. You can refer to the reading

passage as you write.

Narrator: This is the end of the Integrated Skills Writing

Section and of the Audio Program for Practice Test 2. This is

also the end of the Audio Program for The Complete Guide

to the TOEFL Test: iBT Edition.

A NSWER K EY

Section 1: Guide to Reading

(The TOEFL iBT does not use the letters A, B, C, and D for the

multiple-choice items. However, in these answer keys, A cor-

responds to the first answer choice, B to the second, C to the

third, and D to the fourth.)

Preview Test

Biological Barriers

Answer

Explanation

1. A

The word cosmopolitan means “found in most

places in the world” rather than in a limited range.

It is often used about people to mean “worldly and

sophisticated,” but here it is used to describe ani-

mals that live all over the world. The example of

the housefly provides a clue to the meaning of

the word.

■

Bird watchers are familiar with “accidentals,”

which are birds that appear in places far from their

native areas.

2. C

The author compares the concept of biological

barriers with a fence, a familiar type of man-made

barrier: “Just as barbed wire fences prevent cattle

from leaving their pasture, biological barriers pre-

vent the dispersal of many species.”

They may be blown off course by

storms or may be escaping population pressures

in their home areas. Sometimes they may find a

habitat with favorable conditions and “colonize” it.

■

Gardeners are familiar with “volunteers,” culti-

vated plants that grow in their gardens although

■

Section 1 Guide to Reading 87

Besides birds and plants, insects, fish, and mam-

mals also colonize new areas. Sweepstakes routes

are unlike either corridors or filter routes in that

organisms that travel these routes would not be

able to spend their entire lives in the habitats that

they pass through.

13. B, C, Choice B summarizes the information in

E paragraphs 2, 3, and 4 of the passage. Choice C

summarizes the information in paragraphs 5 and

6, and choice E summarizes the information in

paragraph 7. Choices A and F are only details in

the passage. There is nothing in the passage to

indicate that behavioral boundaries are not as

effective as physical or climatic barriers, so choice

D is not a valid answer.

Mysteries of Easter Island

14. A Immense means “large,” “huge.”

15. C All of the statues were carved from volcanic stone

(A) and all of them portrayed human heads (D).

“Some of them” had red stone hats, but only “a

few” had white coral eyes. The statues with white

coral eyes must therefore be the least common.

16. A Paragraph 2 says that “The statues were moved on

a network of roads on rollers made of palm logs

and were then placed on stone bases called ahu. ”

17. B The author says in paragraph 3 that when the first

westerner visited Easter Island in 1722, there were

hundreds of statues standing, but when Captain

Cook visited in 1774, there were only nine stand-

ing. The author then says “Obviously, something

dramatic had occurred during those years.” The

phrase something dramatic refers to the toppling

(knocking over) of the statues.

18. A Paragraph 4 says, “Any commentary about Easter

Island would be incomplete without mentioning

the theories of the Norwegian explorer and scien-

tist Thor Heyerdahl . . .” This means that the

author finds Heyerdahl’s theories important.

However, the author also mentions evidence (such

as the fact that all Easter Islanders are descended

from Polynesians) that contradict Heyerdahl’s the-

ory. Therefore, “important but incorrect” best

sums up the author’s opinion of the theories.

19. D The author says that the Hanau Momoko and

Hanau Eepe were “once mistranslated as ‘Short

Ears’ and ‘Long Ears.’” Since they were “mistrans-

lated,” they must have different meanings.

20. C The author says that “The Hanau Eepe used heavy

earrings to extend the length of their ears.” He also

points out that the ears of the statues resembled

those of the Hanau Eepe. Therefore, the statues

must have had long ears.

21. B Intricate means “complex, complicated, involved.”

22. D In paragraph 6, the author says, “As for the sweet

potato, most scientists now believe that sweet

potato seeds came to the island in the stomachs of

sea birds.”

23. B The author’s main point in paragraph 7 is that

dangers such as “overpopulation and overuse of

resources” can destroy societies.

24. C Thriving means “successful, flourishing, prospering.”

25. You should circle the fourth square. The word they in the

missing sentence links to the word Archaeologists in the

previous sentence, and the sentence explains why

archaeologists think the resemblance between the expert

stonework of the Easter Islanders and that of the Inca was

coincidental.

DNA testing has proven that all Easter Islanders

were in fact descended from Polynesians.

The

current theory is that the Hanau Momoko and

Hanau Eepe were two of perhaps twelve clans of

islanders, all of whom built statues.

■

The “statue

toppling wars” broke out among the clans as the

island became overpopulated. When one group

won a victory over another, they toppled their ene-

mies’ statues.

■

Archaeologists say that the resem-

blance between the stonework of the Easter

Islanders and that of the Inca is coincidental.

■

After all, they say, the statues themselves show

that the islanders were skilled stone workers. As

for the sweet potato, most scientists now believe

that sweet potato seeds came to the island in the

stomachs of sea birds.

26. Hanau Momoko: B, D, I; Hanau Eepe: A, E, F, H.

Choice A refers to the Hanau Eepe. In paragraph 4, the

author says, “The Hanau Eepe used heavy earrings to

extend the length of their ears.” Choice B refers to the

Hanau Momoko: “Heyerdahl theorized that the Hanau

Momoko were Polynesians from other Pacific islands, but

that the Hanau Eepe came later in rafts from South

America.” Choice C does not refer to either group.

Heyerdahl believed there were only two groups of Easter

Islanders. (Current theory believes there were twelve.)

Choice D refers to the Hanua Momoko. The author says,

“He (Heyerdahl) believed that the Hanau Momoko

became the servants of the Hanau Eepe and forced them

to build the statues.” Choice E refers to the Hanau Eepe.

In paragraph 5, the author says, “Another piece of evi-

dence Heyerdahl presented was the fact that the staple of

the Easter Islanders, the sweet potato, is not found in

Polynesia. He believed that it came with the Hanau Eepe

from South America.” Choice F refers to the Hanau Eepe

as well. The author says in paragraph 4, “Because the

Hanau Eepe were the masters, the statues resembled

them.” Choice G does not refer to either group. There is

no mention in the passage that other Pacific Islanders

taught anyone on Easter Island how to make statues.

Choice H refers to the Hanau Eepe. In paragraph 4, the

author says, “According to Heyerdahl’s theory, the Hanau

Momoko eventually rose up in revolt . . . killing off all but

a few Hanau Eepe.” Choice I refers to the Hanau

Momoko. The author says, “According to Heyerdahl’s the-

ory, the Hanau Momoko eventually rose up in revolt,

overturning most of the statues . . . ”

Lesson 1: Factual and Negative Factual Questions

Exercise 1.1

Passage 1

The first known dentist to practice in the North American

colonies was William Dinly, who came to Plymouth Colony

from England in 1630. According to legend, he became lost in

a snowstorm while riding to see a patient and was never seen

again. (1) In most colonial settlements, however, dentistry

was a rare and unusual practice. In emergencies, barbers,

jewelers, and blacksmiths all probably extracted teeth. (2)

One of the first native-born dentists was Paul Revere, the

famous silversmith and patriot. Revere, who began practicing

in Boston in 1768, made false teeth from African ivory. (3)

One of his patients was the Revolutionary War general Joseph

Warren. When the general died at the battle of Breeds Hill,

they never planted the seeds for these plants.

■

88 Section 1 Guide to Reading

Revere identified him by examining his teeth. This was the

first known case of identification by means of dental records.

Today, of course, dental records are commonly used as a

means of identification.

By the early nineteenth century, most communities in the

United States had one or more dentists, although not all of

them had much training. In 1840, dentistry became a true

profession. That’s when the first dental school was opened in

Baltimore, Maryland. The course lasted sixteen weeks. There

were only five students in the first class, and only two of these

graduated. (4) This school has recently been restored as a

museum of dental history. (5)

The most common cure for toothaches was simply to pull

out the offending tooth. Many dentists advertised “painless”

extraction methods in the newspapers of the times.

“Negative Spray” and “Vitalized Air” were two methods of

reducing pain. (6) It is not known today how these mysteri-

ous processes worked, but it is unlikely that they worked very

well. In 1844, dentist Horace Wills had patients inhale the gas

nitrous oxide just before having a tooth pulled. The tooth

could then be painlessly removed. Nitrous oxide, mixed with

oxygen, is still used today to reduce pain during dental proce-

dures. Two years later, in 1846, the dentist William Morton

gave a public demonstration of the effects of ether, which

could be used as anesthesia not only during dental opera-

tions but for surgeries of all kinds. (7)

Another important development in dentistry was the dis-

covery of X rays in 1895. X rays allow dentists to look inside

teeth to discover defects. Early decay, impacted teeth,

abscesses, and bone loss are all things that dental X rays

reveal. (8)

The first dental drills appeared in the 1870’s. They were

Drills were given electric power in the late 1890’s. These

power drills, which were at first called “dental engines,” could

be used for more than drilling cavities. (9) They could also be

used to shape and polish teeth. Quieter, faster drilling equip-

ment aimed at reducing the discomfort of drilling was devel-

oped by John V. Borden in the 1950’s. These drills work at high

speeds to reduce the pressure and vibration caused by older

drills, and are cooled by air or water to reduce the pain

caused by the heat that drilling produces. (10)

Passage 2

A deer’s antlers grow from knob-like bones on the deer’s skull.

Antlers are made of bone, not horn, and are live, growing tis-

sue. (11) They have a constant blood and nerve supply. Deer

use their antlers to fight for mates during the breeding season

or to gain leadership of a herd. (12) Among most species, only

the bucks (male deer) have antlers, but both male and female

caribou and reindeer (which are domesticated caribou) have

antlers. (13) Musk deer and Chinese water deer do not have

antlers at all.

Unlike animals with horns, such as cattle and bison, deer

lose their antlers every year. Those that live in mild or cold

climates lose their antlers in the winter, after the breeding

season. (14) New ones begin to grow out in the early spring.

Deer that live in tropical climates may lose their antlers and

grow new ones at any time of year.

New antlers are soft and tender. Thin skin grows over the

antlers as they develop. The short, fine hair on the skin looks

like velvet. (15) When the antlers stop growing, in early fall,

this velvety skin dries up. Deer scrape their antlers against

trees and shrubs to rub the skin off, an activity called a buck

rub. (16) The full-grown antlers are hard and strong. The

antlers fall off several months later.

Young male deer—called button bucks—develop only

small bumps for antlers during their first winter of life. For

the next few years, the deer’s antlers are small and straight.

(17) As deer mature, their antlers grow larger and form intri-

cate branches. However, contrary to popular belief, it is not

possible to accurately determine ages of deer by counting

their “points” (the branches of their antlers). The size and

shape of a buck’s antlers depend on diet and general health

as well as on genetic factors. (18)

Deer antlers can grow up to one inch (2.5 centimeters) in a

single day. (19) That is the fastest growth rate in the animal

kingdom. Scientists doing cancer research are studying deer

antlers to try to learn how they can grow so rapidly. They

hope that if they can answer that question, they may learn

how cancer cells grow so quickly. (20)

Passage 3

Henry Schoolcraft was a pioneer in the study of Native

American cultures. He studied chemistry and geology at

Middlebury College in Vermont. As a young man, he man-

aged his family’s glassmaking business, and his first book was

a treatise on glassmaking. (21) However, when the family

business failed he decided to head west to explore unknown

territory and write about it in hopes of making a profit. (22)

In 1803 the United Sates purchased the Louisiana Territory

from France. President Thomas Jefferson immediately

authorized the exploration of the vast territory. Meriwether

Lewis and William Clark were chosen to find a pathway to the

Pacific Ocean. Steven Long was sent to explore the Rocky

Mountain region. Zebulon Pike went to the Southwest. (23)

Henry Schoolcraft was chosen to lead an expedition to the

Ozark Mountain region of Missouri. In his book Journal,

Schoolcraft wrote about the minerals, the plants, the animals,

and the people, both Native Americans and white frontiers-

men of the Ozarks. (24)

Later, Schoolcraft was made the chief naturalist for an

exploration party that went to the upper Mississippi River

Valley and the Great Lakes district. (25) He became a negotia-

tor with the Native Americans of the area and was appointed

Indian Agent to the Ojibwa tribe. He married the daughter of

an Ojibwa man and a white woman. He learned to speak the

Ojibwa language. With the help of his wife, he collected a

great deal of authentic folklore of the Ojibwa and other tribes.

(26) He wrote many books on Native Americans and their

history and culture. The famous American poet Henry

Longfellow based his epic poem Hiawatha in part on the

writings of Schoolcraft. (27)

Schoolcraft has his critics, who point out that Schoolcraft’s

research was incomplete and sometimes inaccurate. But he

lived in a romantic age. There is no doubt that he changed his

materials to make them more appealing to his readers. (28)

He invented some of his stories completely and he mixed the

traditions of the Ojibwa with those of other tribes. Despite his

failings, he did succeed in bringing the culture of Native

Americans to the attention of the public.

Schoolcraft’s work contrasted sharply with that of the

ethnographers who worked in the last decade of the nine-

teenth century and the first decade of the twentieth. Their

aim was to achieve complete accuracy in creating a record of

Native American life, which at that time appeared to be in

danger of completely vanishing within a few decades. (29)

Unlike Schoolcraft, they tended to take notes in the original

language. With the development of the phonograph, it

became possible to preserve not just words but also the tone

and emphasis of oral delivery. (30)

Section 1 Guide to Reading 89

Exercise 1.2

Lesson 3: Inference Questions

Exercise 3.1

1. B

2. A

3. C

4. B

5. C

6. B

7. D

8. C

9. A

10. B

11. C

12. D

13. D

14. C

15. A

16. B

17. A

18. C

19. A

20. C

21. D

22. B

23. A

24. C

25. C

26. D

27. D

28. A

29. C

30. B

31. A

32. C

33. B

34. C

35. C

36. B

37. D

38. C

39. B

40. A

41. D

42. B

43. D

1. B

2. C

3. C

4. C

5. A

6. B

7. A

8. C

9. B

10. A

11. B

12. A

13. C

14. C

15. A

Exercise 3.2

1. D

2. A

3. D

4. B

5. C

6. B

7. C

8. A

9. A

10. B

11. B

12. A

13. D

14. A

15. C

16. B

17. A

18. A

19. D

20. C

21. B

22. A

23. D

24. A

25. C

26. C

27. A

28. B

29. C

30. A

31. D

32. B

33. C

34. D

35. C

36. D

37. B

38. B

39. A

40. C

41. D

42. C

Lesson 2: Vocabulary Questions

Exercise 2.1

(Any of the words listed for each item may be considered cor-

rect, and other correct definitions or synonyms are possible.)

1. uninteresting, dull, boring, dreary

2. endless, continuous, unending, continual

3. twilight, evening, sunset, early evening, night

4. basic, simple

5. dim, weak, pale

6. garbage, trash, rubbish

7. wander, travel freely, stray

8. took control, assumed control, took charge

9. course of study, academic program, syllabus

10. optional, voluntary, non-required

11. emphasized

12. group, mass

13. haze, fog, cloud

14. bright, shining, brilliant, radiant

15. fragments, remains, waste, junk

16. a few, a small number

17. grieving, lamenting, weeping, showing sorrow

18. single, lone, sole

19. conspicuous, noticeable, prominent, dramatic

20. clear, see-through

21. searched, hunted, looked

22. fearful, wary, easily frightened

23. avoiding, escaping, evading, getting away from

24. disadvantages, problems, weaknesses, shortcomings

25. responsible, accountable

26. disagreements, arguments, clashes, disputes

27. afflict, upset, bother, trouble, cause problems

28. end, finish, stop, conclude, put an end to, cease

29. cut, carve, divide

30. final, last, eventual

31. tiny, very small, minute, minuscule, very little

32. understand, comprehend

33. magnify, enlarge, expand, increase

34. blurry, unclear, indistinct, hazy, misty

Exercise 2.2

1. B

2. C

3. C

4. D

5. A

6. D

7. B

8. B

9. A

10. A

11. A

Lesson 4: Purpose, Method, and Opinion Questions

Exercise 4.1

1. T

2. F

3. F

4. F

5. T

6. T

7. F

8. T

9. F

10. T

11. F

12. F

13. T

14. F

15. T

16. F

17. F

18. F

19. T

20. T

21. T

22. F

23. T

24. T

25. F

26. T

27. T

28. T

29. F

30. F

31. T

Exercise 4.2

1. B

2. A

3. A

4. B

5. C

6. A

7. D

8. A

9. B

10. D

11. A

12. C

13. D

14. B

15. C

16. A

17. D

18. A

19. C

20. C

21. B

22. A

23. A

24. B

25. A

26. D

27. D

Lesson 5: Sentence Restatement Questions

Exercise 5.1

1. I

2. C

3. X (Note: The original sentence is about the town of

Muncie, not Middleton. )

4. X

5. C

6. X

7. C

8. I

9. X

10. C

11. C

12. X

13. X

14. X

15. I

16. X

12. D

13. C

14. A

15. B

16. D

17. B

18. A

19. C

20. B

21. C

22. A

23. B

24. D

25. D

26. B

27. A

28. A

29. D

30. C

31. A

32. D

33. B

34. A

35. C

36. C

37. C

38. A

39. D

40. B

41. C

Exercise 5.2

1. C

2. A

3. B

4. C

5. B

6. D

7. D

8. A

9. C

10. B

Lesson 6: Reference Questions

Exercise 6.1

1. paintings

2. cut flowers

3. water’s

4. principles used in air conditioning; the human body

5. strands

6. smaller pieces

90 Section 1 Guide to Reading

7. leaves

8. ancient Minoans; archaeological sites

9. mushrooms and other fungi

10. machines based on wheels and gears

11. glaciers in Olympia National Park; altitudes

12. satellite photography

13. American importers

14. New York City; the 1920’s; Paris

15. anemone; its nest

16. Hamlin Garland’s; William Dean Howells

17. fats; three basic types of nutrients; the fat soluble vita-

mins A, D, E, and K; fats

18. The Wisconsin Dells ( or a region along the Wisconsin

River); the strange formations

Exercise 6.2

A gray square placed on a colored square—bright blue

or yellow, for instance—tends to take on the color of the

background.

To a viewer, the gray square actually

seems to have a blue or yellow tinge.

■

The tinge of color

is easier to see if a thin piece of tissue paper is placed

over the squares.

■

When a patch of color is placed on a

background that is approximately complementary—say

red on green—both colors appear brighter and more

vibrant.

■

For this reason, many flags, pennants, and

advertising banners are red and green or bright blue and

yellow.

4. The process of miniaturization began in earnest with the

transistor, which was invented in 1947. This was perhaps

the most important electronics event of the twentieth

century, as it later made possible the integrated circuits

and microprocessors that are the basis of modern elec-

tronics. The transistor was far smaller than the smallest

vacuum tube it replaced and, not needing a filament, it

consumed much less power and generated virtually no

wasted heat. There was almost no limit to how small the

transistor could be made once engineers learned to etch

electronic circuits onto a substrate of silicon.

■

1. D

2. B

3. D

4. C

5. C

6. D

7. B

8. A

9. C

10. C

11. A

12. A

13. D

14. B

15. B

16. C

17. C

18. D

19. A

20. B

21. D

22. A

23. D

24. A

25. A

26. C

27. C

28. A

29. B

30. B

31. A

32. D

33. C

34. D

35. B

36. B

37. C

38. A

39. C

40. A

41. A

In the

1950’s the standard radio had five vacuum tubes and

dozens of resistors and capacitors, all hardwired and

attached to a chassis about the size of a hardbound book.

■

Today all that circuitry and much more can fit into a

microprocessor smaller than a postage stamp. In fact,

the limiting factor in making electronic devices smaller is

not the size of the electronic components but the human

interface.

Lesson 7: Sentence Addition Questions

Exercise 7.1

1. Until the nineteenth century, when steamships and

transcontinental trains made long-distance travel practi-

cal for large numbers of people, only a few adventurers,

mainly sailors and traders, ever traveled out of their own

countries.

There is no point in making a palm-held

computer much smaller unless humans can evolve

smaller fingers.

■

5. When drawing human figures, children often make the

head too large for the rest of the body.

A recent study

offers some insight into this common disproportion in

children’s drawings.

■

In fact, most people never traveled more

than a few miles from the place where they were born.

■

As part of the study, researchers

asked children between four and seven years old to make

several drawings of adults.

■

“Abroad” was a truly foreign place that the vast major-

ity of people knew very little about indeed.

When they drew frontal

views of these subjects, the sizes of the heads was

markedly enlarged.

■

Early map-

makers, therefore, had little danger of being accused of

mistakes even though they were wildly inaccurate.

■

However, when the children drew

rear views of the adults, the size of the heads was not

nearly so exaggerated. The researchers suggest that chil-

dren draw bigger heads when they know that they must

leave room for facial details. Therefore, the distorted head

size in children’s drawings is a form of planning ahead

and not an indication of a poor sense of scale.

6. It has been observed that periods of maximum rainfall

occur in both the northern and southern hemispheres at

about the same time. This phenomenon cannot be ade-

quately explained on a climatological basis, but meteors

may offer a plausible explanation. When the earth

encounters a swarm of meteors, each meteor striking the

upper layers of the atmosphere is vaporized by frictional

heat. The resulting debris is a fine smoke or powder.

■

When mapmakers drew maps, imagination was as

important as geographic reality.

Nowhere is this more

evident than in old maps illustrated with mythical crea-

tures and strange humans.

2. Throughout the centuries, the dream of medieval

alchemists was to discover how to turn lead and other

“base” metals into gold. Some alchemists were fakes, but

many were learned men with philosophical goals. Their

quest was based on the ancient idea that all matter con-

sists of different proportions of just four substances:

earth, water, fire, and air.

■

They believed that it was pos-

sible to adjust the proportions of the elements that made

up lead by chemical means so that it turned into gold, a

process that they called transmutation.

■

Their experi-

ments were concerned with finding the substance, which

they called the philosopher’s stone, that would cause this

astonishing change to take place.

■

This “stardust” then floats down into the lower atmos-

phere, where such dust readily serves as nuclei on which

ice crystals or raindrops can form.

In addition, they

searched for the elixir of life, a substance that could

cure disease and prolong life. They failed to achieve

either of their goals.

■

Confirmation that

this phenomenon actually occurs is found in the

observed fact that increases in world rainfall typically

come about a month after major meteor systems are

encountered in space. This delay allows time for the dust

to settle through the upper atmosphere.

■

However, their techniques for

preparing and studying chemicals helped lay the founda-

tion for the modern science of chemistry.

3. When a small gray square is placed on a larger white

square, the small square appears much darker than when

the same square of gray is placed on a larger black square.

■

Furthermore,

proof that meteors actually create dust clouds can be

seen in the fact that large meteors sometimes leave visi-

ble traces of dust.

■

In a few witnessed cases, dust has

remained visible for over an hour. In one extreme case—

■

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