Main Ideas That Changed the World

Ideas That Changed the World

Ideas that Changed the World combines the quality and breadth of a modern design museum with the high standards of a DK reference title. Stunning photography and beautifully written stories work together to give the reader a unique experience. We don't just show you what's ground-breaking about a space suit, we explain its place in history and space exploration, and the other inventions it has influenced. Readers will be struck with wonder by each item and sense the excitement that so many discoveries inspire.Each subject is introduced through text and a close-up photograph. Captivating icons lead the reader further into the story behind the object and then on to a collections spread featuring similar inventions and developments that shaped the design before and afterward.Some of the incredible inventions and ideas featured are: microscope (Charles Darwin s), telescope (Isaac Newton's), antibiotics, elevators, eyeglasses, the bicycle, auto pilot, the blackboard (as used by Albert Einstein), tin cans, umbrellas, buttons, TV, satellites, submarines, Captain Cook's travel cooking implements, the wheel, cement, a volcanologist's heat-proof uniform, the first Roman coin, bar codes, the first video game, the Walkman, the first Apple computer, surf boards, film animation, and much, much more!
Categories: History
Year: 2010
Language: english
Pages: 258
ISBN 10: 0756665310
ISBN 13: 9780756665319
File: PDF, 57.45 MB

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THE

BIG
BIG IDEAS
IDEAS
THAT
CHANGED
THE

WORLD
Incredible inventions and
the stories behind them

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Authors

Julie Ferris, Dr. Mike Goldsmith, Ian Graham, Sally MacGill,
Andrea Mills, Isabel Thomas, and Matt Turner

Consultant
Roger Bridgman

LONDON, NEW YORK,
MELBOURNE, MUNICH, AND DELHI
Project editor Camilla de la Bédoyère
Editors Sally MacGill, Theresa Bebbington
Project art editor Ralph Pitchford
Art editors Sandra Doble, Steve Woosnam Savage
Senior editor Shaila Brown
Senior designer Spencer Holbrook
Designers Johnny Pau, Jane Thomas, Stefan Podhorodecki
Managing editor Linda Esposito
Managing art editors Diane Thistlethwaite, Jim Green
Category publisher Laura Buller
DK picture library Emma Shepherd
Picture researcher Karen VanRoss
Additional picture researchers Ria Jones, Jenny Faithful, Sarah Hopper
Production editor Marc Staples
Senior production controller Angela Graef
Jacket designer Laura Brim, Sophia M.T.T.
Jacket editor Matilda Gollon
Development team Jayne Miller, Laura Brim
Design development manager Sophia M. Tampakopoulos Turner
First published in the United States in 2010 by
DK Publishing, 375 Hudson Street
New York, New York 10014
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Copyright © 2010 Dorling Kindersley Limited
All rights reserved under International and Pan-American Copyright Conventions.
No part of this publication may be reproduced, stored in a retrieval system, or transmitted
in any form or by any means, electronic, mechanical, photocopying, recording,
or otherwise, without the prior written permission of the copyright owner.
Published in Great Britain by Dorling Kindersley Limited.
DK books are available at special discounts when purchased in bulk for
sales promotions, premiums, fundraising, or educational use. For details, contact:
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SpecialSales@dk.com
A catalog record for this book is available from the Library of Congress
ISBN: 978-0-7566-6531-9
Hi-res workflow proofed by MDP, U.K.
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Discover more at
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GENIUS
10
Introduction
Lightbulb

12

Antibiotics

14

Penicillin

16

Vaccination

18

Microscope

20

X-ray

22

DNA

24

Watson and Crick

26

Radioactivity

28

Tin can

30

Portland cement

32

Hoover Dam

34

PET bottles

36

Stainless steel

38

Telegraph

40

Who invented the telephone?

42

World Wide Web

44

Laser

46

LCD

48

Nylon

50

Wallace Carothers

52

Dynamite

54

Contents

GREAT
GIZMOS

HANDY
GADGETS

56

106

Engine

58

Microwave

108

Elevators

60

The first microwave

110

Elisha Otis

62

Digital camera

112

Refrigerator

64

Glasses

114

Wind turbine

66

Radio

116

Electric motor

68

Marconi

118

The father of electricity

70

Money

120

Spinning jenny

72

Credit card

122

Robots

74

Cash register

124

Robots in our world

76

James Ritty

126

Pendulum clock

78

Bar code

128

The master of time

80

Stapler

130

Crane

82

Stamp

132

Printing press

84

Post-its

134

Flushing toilet

86

Velcro

136

Television

88

Zipper

138

From script to screen

90

Cell phone

140

Solar cell

92

Going mobile

142

Clean energy

94

Battery

96

Microprocessor

98

From valves to microprocessors

100

Apple computer

102

Wozniak and Jobs

104

ON THE
MOVE

EXPLORE

144

178

Wheel
Ford Model T
Ford’s model factory
Sailing ship
Submarine
Jet plane
Helicopter
Steam locomotive
Full steam ahead
Bicycle
Cat’s eye
Percy Shaw
Electric car
Metro
London Underground

146
148
150
152
154
156
160
162
164
166
168
170
172
174
176

Saturn V
Hubble
Hubble in action
Compass
Mars rovers
GPS
Cassini
Spacesuit
Space helmet
Submersible
Scuba
Jacques Cousteau
Fiber-optic endoscope
MRI

180
182
184
186
188
190
192
194
198
200
202
204
206
208

CULTURE
210

Ballpoint pen
Umbrella
LEGO® brick
Play well
Walkman
Skateboard
Newspaper
Jeans
Levi Strauss
Kinetoscope
What is 3-D?
Video games
Sunglasses
Electric guitar
Sports shoes
Soccer

212
214
216
218
220
222
224
226
228
230
232
234
236
238
242
244

Time line
Glossary
Index

246
248
252

Contents

As Thomas Edison stated,
inventions are mostly hard
work. But without a big idea to
begin with, they would never
happen at all. And without these
big ideas and the inventions they
lead to, our lives would be very
different. They have changed
the way we live and think and
changed the course of history.
Ideas in action
Just look around you—how
many of the things you
can see didn’t have to be
invented by someone? In fact,
without inventions, many of
us wouldn’t even be alive—
medicines and machines start
keeping us safe and healthy
even before we are born
and continue protecting us
throughout our lives. Some
inventions keep us in touch
with our friends, allow us to
explore our world, or help
solve the mysteries of the
universe, while others simply
help us enjoy ourselves.

Introduction
8

“

Genius is one percent
inspiration and
ninety-nine percent
perspiration

”

Thomas Edison,
American scientist and inventor

Changing the world
For many centuries, most
inventions started as the big
idea of a single person. That
began to change around a
century ago, and soon colleges,
big companies, and even entire
governments were helping
develop new ideas and turn
them into reality. When they
work together, large groups of
people can do amazing things,
from wiping out diseases to
flying to the Moon. It’s said
that more things were invented
in the 1900s than in all the
centuries that came before,
and it’s impossible to imagine
just how many more things
will be invented during
this century.

9

Genius
What does it take
to be a genius? It might
require years of study, endless
experiments, the work of a
lifetime. Or it might happen
in a moment, with a single idea.
An idea that changes the world. . .

1881
JOSEPH SWAN AND
THOMAS EDISON

The discovery of electricity sparked
a race to design electric lights that were small
and safe enough to be used at home. Englishman
Joseph Swan and American Thomas Edison hit
on the same bright idea: a glowing electric wire
sealed inside a vacuum. They teamed up to sell
their inventions, and in 1881, the first
commercial lightbulbs were produced. People
were no longer limited to candlelight to see in
the dark. For the first time, doctors, craftspeople,
and factory workers could see well enough to
work at night. Streetlights made traveling safer.
Miners no longer carried dangerous naked
flames. Within 25 years,
millions of homes were
lit by electric lamps.

BRIGHT SPARKS

Edison and Swan built upon decades of research to use
electricity to make light. Sir Humphrey Davy made a key
breakthrough in 1809. He found that an arc of electricity
jumps between two carbon sticks to complete a circuit,
heating the carbon until it glows.

Electrical system
Edison was one of the world’s greatest
inventors and had 1,093 patents for his
ideas. To make his lightbulb useful, he
designed an entire system to generate
and supply electricity to buildings. His
inventions include safety fuses, light sockets,
switches, and all the equipment that
delivers electricity from power plants
to homes in the right amounts.

Edison and Swan both
created vacuums inside
their bulbs—with no
oxygen around it, the
filament can get white-hot
without catching fire

The gas argon
eventually replaced the
vacuum inside bulbs

Electricity passes through
the filament, heating it to
furnacelike temperatures

The bulb had to be
sealed after the air was
carefully forced out,
using a special pump

In 1909, fragile carbon filaments
were replaced by fine tungsten
wires, which were easier to
handle and lasted longer

Lightbulb
12

COOL SCIENCE
If you uncoil
a lightbulb
filament,
it is 20 in
(51 cm) long

Warnings
At first, people were suspicious of the
new technology. Warning signs were
necessary to remind them not to light
bulbs with matches. Customers had
to be reassured that electric lamps
would not damage their health or
affect their sleep.

Wires heat up as electricity
passes through them. If
they get hot enough, they
glow as electrical energy is
changed into light as well as
heat. Long, thin coiled wires
produce the brightest light.
Modern filaments have coils
so small, they can be seen
only with a microscope.

Popular light source
Lightbulbs made electric lighting
affordable. Although they are more
than 100 years old, Edison’s original
bulbs look very similar to today’s
incandescent bulbs. Easy to use,
they have become the world’s
most popular source of light.

A good source of light?
As countries around the world look
for ways to reduce energy use, new
types of lightbulbs are stepping
into the spotlight.

More heat than light
Although cheap to produce, modern
lightbulbs convert just 4–6 percent of
their electricity supply into light. The rest
is wasted as heat.

The term “lamp” originally
referred to the bulb, but
today we use it to refer to
the fitting that holds it
Early Swan lamp

Energy-saving bulb
Compact fluorescent bulbs use one-quarter
of the energy and last 10 times longer than
filament bulbs. A coating on the glass glows
as electricity passes through the gas inside.

The bulbs slot into
fittings that make
contact with the
electricity supply
Early bases, such as this
wooden one, were eventually
replaced by a screw-in base
invented by Edison

Lighting the future
Light-emitting diodes (LEDs) produce little
heat and have been used since the 1960s.
New-generation LED bulbs are bright
enough to light rooms and last for 25 years.

SEE ALSO X-ray 22 · Television 88

13

1928

TOMORROW’S WORLD

ALEXANDER FLEMING

For most of human history,
disease-causing bacteria were our deadliest
enemies. During World War I, more soldiers
died from infections than fighting—even
a scratch from a thorn could be lethal.
Alexander Fleming’s accidental discovery of
a substance that could kill bacteria without
harming human cells changed the course
of history. Antibiotics have helped people live
longer, healthier lives and transformed the
way in which new drugs are developed.
Deadly invaders
Bacteria are microscopic organisms.
Many “friendly” bacteria live inside
us without doing any harm, but
disease-causing bacteria release
chemicals that damage our cells.
They cause some of the
deadliest human diseases,
including pneumonia,
tuberculosis, and
the plague.

Bacteria, such as Salmonella (above), can rapidly change, making
it difficult to treat the disease that they cause. Scientists are
hoping to create new synthetic antibiotics that will target all
types of bacteria even more effectively than natural ones can.

U.S. doctors prescribe
150 million doses of
antibiotics every year

Seek and destroy
Each antibiotic fights bacteria in a different way,
stopping them from growing or reproducing
normally. Penicillin, for example, stops bacteria
from building their protective cell walls, so the
bacteria are damaged or burst as they grow.

The first antibiotics
were injected or
used on skin wounds—
most are now taken
by mouth (orally)

Antibiotics
14

Antibiotic capsules are
made from gelatin or
other digestible materials

Miracle mold
Fleming discovered the first antibiotic when he left a dish
of Staphylococcus bacteria uncovered for several days. Spores
of Penicillium notatum mold, closely related to ordinary bread
mold, drifted into the dish and began to
grow. Fleming realized that the
mold produced a chemical
that was poisonous to
bacteria—he called
this penicillin.

The fight continues
Penicillin’s success led to a scramble
to find new antibiotics. In the 1950s,
the discovery of streptomycin and other
antibiotics made diseases—including
tuberculosis—curable. People pictured
a world free of infections, but bacteria
began to fight back.

Halos of
dead and
dying bacteria
appeared around
the blue mold

Viruses
Antibiotics don’t harm viruses. However,
they are vital to the development of
virus-busting drugs. They are added to eggs,
which are used to grow viruses for research
and stop bacteria from infecting them.

Coatings can be
added to capsules so
that they dissolve in the
intestine, protecting the
penicillin from stomach acid

A growing problem
The use of antibiotics is not tightly
controlled—doctors prescribe them for
virus infections, patients take incorrect
doses, while farmers feed them to
livestock. All of these things help new,
antibiotic-resistant bacteria evolve.

Your body breaks down penicillin
after around four hours, so
capsules must be taken frequently
SEE ALSO Vaccination 18

15

Penicillin
Alexander Fleming was the first
person to investigate penicillin’s
bacteria-busting effects. However, it was
the work of two lesser-known scientists that
gave doctors the ability to fight bacteria with
antibiotics. Ernst Chain and Howard Florey
separated the antibacterial substance from
the mold that produces it and used this to
make a life-saving drug.
Purifying penicillin
Fleming tested his Penicillium mold on different
types of bacteria and discovered that it killed those
that caused pneumonia, syphilis, and diphtheria.
It was also harmless to humans, unlike the antiseptics
that were in use at the time—these chemicals
killed bacteria but also damaged human cells. He
published his research in 1929, pointing out that if
penicillin could be extracted, it would be very useful
in medicine. A decade later, Chain read Fleming’s
paper and suggested that he and Florey try to purify
penicillin. By 1940, having tested it successfully on
mice, they had extracted and purified enough
penicillin to try it out on a human patient.

Ernst Chain

Howard Florey

German-born Chain was an
excellent biochemist who had
left Berlin a few years before
joining Florey’s team in England.

Florey led the Oxford University
laboratory that rediscovered
penicillin. Unlike Fleming, he
did not like media attention.

16

Alexander Fleming
Fleming was a bacteriologist
at Saint Mary’s Hospital, in
London, England. His first major
discovery was that mucus from the
nose has mild antibacterial effects.
This work helped him see the
significance of the moldy dish.

New sources
Florey and Chain had so little
penicillin, they had to remove the
drug from their first patient’s urine
and reinject him with it. Finding it
difficult to extract enough penicillin
from Penicillium notatum, Florey
launched a worldwide search for a
more productive strain of the mold.
Finally in 1943, a lab worker brought
in a moldy melon from a local
market. This became the source of
most antibiotics for the next decade.
Making an antibiotic
Florey and Chain’s successful trials with
penicillin helped persuade companies
to produce the drug on a large scale.

Penicillin for all
Production of penicillin was led by
American companies, but it was
not long before the technology was
used by other countries, helping
resolve the lack of supply.

Prizes and predictions
In 1945, Fleming, Florey, and
Chain won a Nobel Prize for their
work. Fleming made a speech
predicting today’s problems of
antibiotic resistance—taking too
little could expose bacteria to
small, nonlethal quantities of the
drug and allow them to become
resistant. Few took notice of
Fleming’s warnings.
Military orders
The first penicillin stocks were sent
straight to soldiers wounded on the
battlefields of World War II. The
“miracle drug” dramatically reduced
deaths from infected wounds, and
penicillin became a household name.

17

1796

The cowpox virus is
still used to make
smallpox vaccines

EDWARD JENNER

Smallpox was once a common disease,
killing most victims and leaving survivors
with terrible scars. In 1796, Edward Jenner
discovered that exposing people to the milder
disease of cowpox prevented them from
catching smallpox. He called his technique
vaccination. A century later, Louis Pasteur
figured out how to make vaccines for other
diseases, triggering a massive advance in
the fight against diseases. Vaccines have
since been developed for many serious
diseases, saving millions of lives.

The test
Jenner’s work was remarkable at a time when no
one knew that microorganisms, such as viruses and
bacteria, could cause diseases. Working as a doctor,
Jenner discovered that milkmaids who caught
cowpox became immune to smallpox. He tested
his theory by infecting an eight-year-old boy with
cowpox. Two months later, Jenner transferred some
pus from a smallpox victim into a cut on the boy’s
arm. The boy did not develop smallpox.

Metal syringes are often
used to vaccinate animals—
humans are vaccinated
with smaller, disposable
needles or syringes
Vaccines come in
different forms—many
are injected, but some
are taken by mouth

Vaccination prevents
more than two million
deaths every year

Vaccination
18

Creating vaccines
In 1879, Pasteur decided to try and make milder forms of other
diseases to use as vaccines. He heated anthrax bacteria to stop
them from causing a deadly disease. The damaged bacteria were
injected into animals. Later, the animals were injected with real
anthrax and survived. Vaccines are still made from dead
or weakened microorganisms using Pasteur’s methods.

Milestones in medicine

Fighting diseases
Pasteur’s pioneering work prompted research into new
vaccines. Once-common diseases like tetanus, rabies,
measles, polio, and diphtheria can now be controlled
and prevented by vaccination. Newer vaccines target
the viruses that cause certain cancers.

Vaccination is a quick,
easy, and cost-effective
way to prevent diseases

Vaccinations have given scientists and
doctors a greater understanding of the
immune system and how it destroys
invading microorganisms and viruses.

A plunger forces
the liquid through
the needle

Protection on a large scale
Vaccination prevents diseases from
spreading, protecting entire communities
as well as individuals. Mass vaccination for
children is now routine in many countries.
How vaccines work
The weakened
microorganisms are
attacked and destroyed
by your immune system.
If the disease-causing
microorganisms later invade
your body, your immune system
“remembers” how it fought the
vaccine and quickly springs into
action—killing the microorganisms.

TOMORROW’S WORLD

The end of smallpox
The last death from smallpox (above)
was in 1977, following a huge program
of vaccination that was coordinated by
the World Health Organization.

Vaccines are biological
products, so they
have to be stored
and used carefully

Science is still searching for vaccines against many deadly
diseases, including malaria, which is transmitted by
mosquitoes. Malaria infects more than 240 million people per
year and caused more than 860,000 deaths in 2008 alone.

Organ transplants
Immunology (understanding the immune
system) made organ transplants possible.
Doctors can stop the recipient’s body from
treating the new organ like a disease.

SEE ALSO Antibiotics 14 · Microscope 20

19

20

Microscope

Hooke added a third
lens inside this barrel to
increase the visible area
of the specimen

The signal is displayed
on a monitor

Modern-day scanning electron
microscopes use magnets
to move a beam of tiny
negatively charged particles,
called electrons, across the
object being examined.
Electrons from the specimen
are knocked loose and picked
up by a detector, which feeds
the information to a display.

The electron beam hits the
specimen, and electrons from
the specimen are scattered

The electrons reflected off
the specimen are collected
and turned into a signal

Magnetic coils act
like lenses, focusing
the beam of electrons
on to the specimen

A beam of fast moving
electrons is fired into
the microscope

COOL SCIENCE

HANS AND ZACHARIAS
JANSSEN

The barrel was made
of wood, covered
with thin leather

The microscope’s
barrrel was secured
to a metal stand

From spectacles to spectacular
In the 1590s, magnifying lenses were used widely in
spectacles, so it’s not surprising that a spectacle-maker
invented the compound microscope. Hans Janssen and his
son Zacharias realized that if one lens magnified a little, two
could magnify more. A compound microscope is one that
uses more than one lens to magnify (make bigger) an image.

Microscopes zoom in on details that
are invisible to the naked eye. They
are among the most useful of all scientific
instruments, because they give us an insight
into how things are structured and
how they function. This 16th-century
invention led to the discovery of cells
and microorganisms and has unlocked
many secrets of life, death, and diseases.

Robert Hooke (above) and
Anton van Leeuwenhoek
began microscope-based
research in the 1600s

Hooke’s compound
microscope had three
lenses—the eye lens
was at the top

1590

SEE ALSO Vaccination 18 · Spectacles 114 · Hubble 182

21

The image
could be
focused using
this screw

Better lenses led to more
powerful microscopes.
As microscopes improved,
scientists delved deeper
into the detail of life. Their
discoveries were crucial to
the development of science
and medicine.

Leeuwenhoek’s microscope
In 1676, Leeuwenhoek used his simple
microscopes to study plaque scraped
off his teeth. He was amazed to see
tiny “animals” moving around—he
had discovered microorganisms.

A magnifying lens
was in the snout

The barrel could
be angled using a
ball-and-socket joint

Amazing discoveries

The world’s most
powerful microscope
magnifies 14 million
times, revealing
individual atoms

Light and lenses
Lenses are pieces of glass with
curved sides that bend light rays.
The Janssens placed a lens at
each end of a tube, creating a
microscope that made objects
appear 10 times bigger. In the
1670s, Anton van Leeuwenhoek
made single-lens microscopes that
could magnify objects 200 times.

Germ theory
Two hundred years later, Louis Pasteur
used microscopes to study bacteria in
diseased animals. His theory that
microorganisms caused diseases
revolutionized medicine.

Modern microscopes
Electron microscopes were invented in
the 1930s, becoming so powerful that
they allowed scientists to see atoms for the
first time. The latest models can reveal a
specimen’s physical and chemical properties.

Specimens were mounted
on this pin and lit by
light from an oil lamp

Tiny worlds
Robert Hooke used a
compound microscope to
examine thousands of objects
and living things. In 1665, he
published a bestselling book, called
Micrographia, which was packed
full of drawings of the strange
and exciting details that he’d seen.
His most important discovery was
the cell, which is the building block
of plants and animals.

Hooke’s drawing of
thin slices of cork from
trees revealed that
plants were made up
of tiny structures,
which he called cells

1895
WILHELM RÖNTGEN

The accidental discovery of x-rays,
a type of radiation, in 1895 astonished the world
and changed science, industry, and medicine
forever. Physicists, including Marie Curie, began
researching new areas, leading to the discovery
of radioactivity. Industry began using x-rays
to find faults in machines and materials. In
medicine for the first time, doctors could look
inside people’s bodies without cutting them
open. X-rays are now used
worldwide to detect broken
bones, bad teeth, swallowed
objects, and even tumors.

X-rays expose
photographic film in
the same way that light
does—the more rays
that hit the film, the
darker it gets

X-rays have more
energy than light, so
they can travel through
different materials

Discovering the unknown
As Wilhelm Röntgen studied radiation from a
cathode ray tube, he noticed a mysterious green
light. He realized that unknown invisible rays had
penetrated a cardboard barrier and were making
a patch of fluorescent paint glow.

BRIGHT SPARKS
In the mid-1800s, scientists
began pumping the air out of
glass tubes in order to study
glowing beams known as
cathode rays. In the 1870s,
scientist William Crookes
invented a better cathode ray
tube that led to amazing
breakthroughs in physics.
Crookes tubes were used to
discover electrons, plasmas,
x-rays, radioactivity, and even
led to the first television sets.

X-ray
22

X-rays are a type
of electromagnetic
radiation, like light
and radio waves

The x-rays leave a
silhouette, or the shape,
of objects that they
can’t travel through,
such as metal jewelry

Penetrating power
Röntgen excitedly experimented with
the new rays. He found that they passed
straight through many objects. The most
startling result came when he placed
his wife’s hand between the beam
and some photographic film.
He’d discovered a way to
photograph the bones
inside the body.

Bones let few x-rays
reach the film—these
show up as white
“shadows,” and help
doctors see fractures

X-rays were
named after the
mathematical symbol
for an “unknown”

Looking inside
X-rays let us look inside things that
are dangerous, difficult, or inconvenient
to take apart—from the human body
to gas pipelines and complex
electronic equipment.

Probing proteins
An x-ray image can reveal the structure
of miniscule molecules, such as this
flu virus. This helps scientists design
effective medicines.

Peering into the pelvis
CAT scanners use multiple, moving x-ray
beams to scan the body from every angle.
A computer then builds detailed images,
helping doctors find unhealthy tissue.

Soft tissues, such as
flesh, let more x-rays
through, so they
appear gray

Invisible danger
By 1927, scientists realized
that radiation could kill cells
and cause cancer. Doctors began
to use shields and small doses to
protect themselves and their patients.
The harmful effects have also been
harnessed to treat diseases, by zapping
cancer cells with x-ray beams.

Catching criminals
X-rays are a quick and easy way to screen
bags and luggage at airports and other
places where both security and speed
are important.
SEE ALSO DNA 24 · Radioactivity 28 · Television 88

23

1953

BRIGHT SPARKS

FRANCIS CRICK AND
JAMES WATSON

Humans have always been interested
in what gives living things their characteristics,
and how this information is passed from one
generation to the next. The unraveling of DNA
and the science of genetics was one of the
greatest achievements of the 1900s.

In the 1860s, Austrian
monk and scientist
Gregor Mendel
experimented with pea
plants. He figured out
that simple characteristics,
such as flower color,
are determined by two
hereditary factors, one
from each parent. Today,
we call those hereditary
factors genes.

Information carriers
Genes are carried on structures
called chromosomes found in the
nucleus of a cell. It was in the
1940s that scientists discovered
chromosomes are made of
long strands of tightly coiled
deoxyribonucleic acid (DNA).

The four letters are different
chemicals called bases—shown
as four different colors

DNA is a simple four-letter
alphabet that acts as a code,
telling cells how to make proteins

DNA
24

What is DNA?
Scientists James Watson and Francis Crick discovered the
structure of DNA in 1953, finally explaining how genes carry
information. Each gene is a length of DNA that tells a cell
how to make a specific protein. Humans, animals, and plants
need many different proteins in order to live and grow.

COOL SCIENCE
DNA can make copies
of itself, which is essential
for living things to grow
and reproduce. The double
helix “unzips,” and each
half of the ladder acts as
a template. The separated
bases attract new partners,
building two identical
double helices (plural
of helix).

The bases pair up
like rungs on a ladder,
linking together two
chains of DNA

A molecule of DNA
is made up of two
strands that twist
around one another

Each backbone
and its bases
make one chain
The bases are linked together
in long chains by a “backbone”
made of carbon, hydrogen,
oxygen, and phosphorus

The science of genetics
Genetics is the scientific study of genes—the hereditary
factors in DNA. They affect almost everything about us,
from how we look and behave to the illnesses that we
might get as we grow older. Studying DNA helps us
understand why some cells don’t work properly and
could lead to cures for many diseases in the future.
Genetics has also given us DNA fingerprinting and
genetic engineering (changing an organism’s DNA
to give it useful new characteristics).

TOMORROW’S WORLD

The uncoiled DNA from
a single human cell is
almost 6 ft (2 m) long

Colonies of bacteria can be given genes that make them
light up every hour or so. If conditions change, the timing
changes. Putting these bacteria into patients could warn
doctors when body conditions change, so that every patient
gets their medicine when they need it.

SEE ALSO Antibiotics 14 · X-ray 22

25

k
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27

1896
HENRI BECQUEREL

As 19th-century scientists
explored the nature of atoms,
they discovered some materials with
very special properties. Radiating
(giving off) energy as tiny particles
and rays, these radioactive materials
have led to huge advances in
medicine and scientific research.
We have also learned how to release
the enormous nuclear energy stored
inside their atoms. There have been
serious destructive consequences, but
nuclear power now produces one-sixth
of the world’s electricity. It does so without
releasing global-warming gases, using a
fuel found in rocks all around the world.
Fuel rods contain
pellets of uranium fuel

Radioactive elements
In 1896, the French physicist Henri Becquerel discovered
that the metal uranium gives off radiation. Soon, other
elements (substances that contain atoms of all one type)
that are naturally radioactive were also found. In today’s
nuclear reactors, we can also make some elements
become radioactive. Over time, all these gradually
change into different chemical elements.

A uranium fuel
pellet the size of a
grape contains as
much energy as
three and a half
barrels of oil

When lowered into the
reactor, the bundle of
rods will provide energy
for three or four years

This French nuclear power
plant produces enough
electricity to boil 600,000
kettles at the same time

The Curies
French scientists Marie and Pierre Curie were
interested in Becquerel’s mysterious rays. In 1898, they
discovered three new elements that give off radiation.
Marie realized that radiation comes from the atoms of
these elements. She called this property radioactivity.
In 1903, Marie became the first woman to win a
Nobel Prize, shared with Pierre Curie and Becquerel.

Radioactivity
28

Nuclear power
Radioactive atoms are unstable. Bombarding them with
even smaller particles called neutrons can split them apart.
This process—called nuclear fission—releases huge
amounts of energy as heat and radiation. A nuclear reactor
harnesses this to create steam for generating electricity.

High-energy radiation
is deadly, so power plant
operators use machines
to handle the fuel

Wider uses of radioactivity
We can detect even tiny amounts of radiation. Doctors use
radioactive elements to trace the paths of chemicals inside
the human body to study how the body works and diagnose
diseases. Carefully targeted doses of high-energy radiation
can also kill cancer cells. In industry, radioactive elements
and sensitive detectors are used to check the thickness of
materials like paper and plastic wrap as they are made.
Scientists also use radioactive tracers. The amount of
radiation given off by naturally radioactive elements tells
us the age of ancient plant and animal remains.

The water’s blue glow
shows the strength of
the nuclear reaction
The splitting of uranium
atoms takes place inside
the reactor’s core

TOMORROW’S WORLD
Rocks that contain
uranium are taken from
mines (left), but mining
can contaminate land and
water with radioactive
waste. This is harmful to
living things. Scientists are
exploring ways to clean up
this waste. One possible
method is to use a type
of bacteria that “eats”
radioactive uranium and
makes it safer.

SEE ALSO X-ray 22 · Solar cell 92

29

1810

BRIGHT SPARKS

PETER DURAND

First used by sailors, soldiers,
and explorers, tin cans can still provide lifesaving food supplies. But since the 1920s, they
have become essential, convenient, long-lasting
food stock items in most households. Almost
all foods can be canned, from the cheapest
tomatoes to the finest caviar. Easily recycled
and needing no refrigeration, cans are also one
of the most environmentally friendly ways to
preserve food. This means that people may
still be using them in hundreds of years’ time.
The first tin cans
In 1810, Englishman Peter Durand
created tin cans by dipping sheets of
metal into molten (melted) tin and
connecting pieces together with a
soldering iron. The first canning
factory was built near London,
England, in 1812, and by 1815
British troops were eating canned
food at the Battle of Waterloo.

In the 1700s, many soldiers
died of hunger while at war,
so France offered a cash prize
to anyone who could think
of a new way to preserve
food. In 1810, Nicholas
Appert won the prize. It had
taken him 14 years to find a
method that worked—boiling
food that was then sealed
inside glass jars.

Gravy soup cans, 1899
Early cans were iron, but
now most food cans are
steel, and drinks cans
are aluminum

Workers rolled metal
rectangles to form the
cylinders—some cans
are still made in this way

In 1813, a can of meat
cost nearly one-third of
a laborer’s weekly income
A slow start
For years, production was very slow.
Skilled tinsmiths made just six cans per
hour by hand, which were then boiled
for at least five hours. By 1846, machines
could manufacture 60 cans per hour, but
today’s machines can make a thousand per
minute. We now boil the food very quickly,
at high pressures and temperatures.
A thin layer of tin
stopped the inside
from rusting

Tin can
30

Tinsmiths soldered the ends
of the can to the cylinder
after hammering the edges
down with a mallet

Stopping the rot
For many years, people canned food
without knowing how the process worked.
In the 1850s, Louis Pasteur showed that
boiling food killed the bacteria and mold
that cause decay. Sealing the cans
prevented more live microorganisms
from reaching the food.

Old chicken
On their 2006 wedding anniversary,
Les and Beryl Lailey opened a can of
chicken 50 years after receiving it as
a wedding present; it still tasted fine.
Use-by dates are usually for two years,
but if properly sealed, canned food
may never go off.

Preserving food
People have been trying to preserve
food since ancient times. This means
either killing bacteria and molds or
stopping them from growing.

A small hole, soldered closed
afterward, let air escape
while the food boiled

Opening cans
involved a hammer
and chisel until Ezra
Warner invented the
can opener in 1858

This gravy soup
was for soldiers
in the Boer War
(1899–1902) to
make beef tea

Traditional methods
The ancient Egyptians found that drying
fruit in the sun made them last longer. For
centuries, we have also smoked or salted
meat and fish and pickled foods in vinegar.

Freezing
Microorganisms cannot function at freezing
temperatures, and some die. But frozen food
was not common outside cold countries until
the invention of refrigeration.

Much thicker than
modern cans, early
cans often weighed
more than the
food inside

Tinsmiths used lead solder
(a mixture of melted metals)
to seal cans, not realizing that
it was poisonous

Freeze drying
This method dries frozen food without
damaging its structure. Adding water will
return it to its original state, even years later.

SEE ALSO Microscope 20 · Refrigerator 64

31

1824
JOSEPH ASPDIN

Much of the modern world is built
from concrete, as it is cheap, hard-wearing,
and does not burn. Almost all of this concrete
has been made with Portland cement. Cement
is a vital ingredient of most civil engineering
structures, such as roads, bridges, and sewers.
We also use it in mortar, to plaster walls, and
to lay bricks. Ancient civilizations used natural
cements, but Portland cement is consistently
strong and easy to produce, which is why it
has been such a massive success.
After water, concrete
is the most widely
used substance
on Earth

Most concrete and mortar
mixes have more than twice
as much sand as cement

Cement, which makes
up around 10 percent of
concrete, is the glue that
binds together sand and gravel

Concrete hardens because
of a chemical reaction—
called curing—between
cement and water

Fortune seekers
In the early 1800s, factories produced natural
cements of limestone and clay. But their quality
varied with the minerals found in the ground.
Many people tried to make their fortunes with
the perfect man-made cement. However, nobody
understoond the chemistry of concrete, so they
could only experiment by trial and error.

Gravel gives concrete
bulk and strength, but
it is missed out when
making mortar
Fibers or chemicals
can make concrete
even stronger

Portland cement
32

Early concretes
In ancient times, many people used
mud or dung as natural cements.
Some also made long-lasting concrete
from materials available locally.

To cast concrete, builders
pour well-mixed cement,
sand, gravel, and water into
molds known as formwork

Success in the kitchen
In 1824, British bricklayer Joseph
Aspdin burned crushed limestone
with clay in his kitchen and then
ground it into a powder. He had
found the recipe for an artificial
cement that reacted with water to
become much stronger. It made
gray concrete that looked like
high-quality Portland stone, so
he called it Portland cement.

Concrete-tipped pyramids
Most scientists now agree that, rather than
hauling huge stone blocks to the top of
pyramids, the ancient Egyptians probably cast
some in place using a clay-based concrete.

Cables support the new
concrete while the
bridge is being built

From strength to strength
Aspdin’s son William, who ran
Portland cement factories, improved
the recipe with higher temperatures
and modified ingredients. French
gardener Joseph Monier invented
reinforced concrete in 1867. His
concrete plant pots with steel mesh
paved the way for today’s massive
reinforced concrete structures.
Its curved shape
helps the bridge
carry more weight

These are cast on
site, but concrete
blocks are often
precast in factories

Without steel
reinforcement
bars, this 2,120-ft(645-m-) long
bridge would
collapse

Ancient Roman ash
The Romans used ash from volcanos to make
strong concrete. They changed its properties
by adding blood, milk, and horsehair.

BRIGHT SPARKS
In 1756, John Smeaton built a
stone lighthouse off the U.K. coast.
He noted that unlike ordinary
mortars of limestone and sand,
those that also had a high
proportion of clay became harder
in water and could withstand the
pounding of the waves. Shown
here is the lighthouse, which was
rebuilt on land as a memorial.

SEE ALSO Stainless steel 38

33

Hoover Dam
Built in the 1930s during
America’s Great Depression,
the Hoover Dam still stands as one
of the most impressive feats of civil
engineering ever. It took around
200 engineers and 20,000
construction workers to dam the
Colorado River at Black Canyon.
The concrete that they cast could
have built a sidewalk 4 ft (1.2 m)
wide all the way around the planet.
Camping in Ragtown
Months before dam building began in 1931,
tens of thousands of men arrived at the site
in search of jobs. They brought wives and
children, but little money. Families camped
in terrible conditions in a dry, barren spot
that they called Ragtown. Diseases were rife,
and the heat killed 25 people in the hot June
and July of 1931. The following year, the
government built Boulder City, where
many of the workforce and their families
lived until the dam was completed in 1936.
Monkeys, Puddlers,
and Scalers
Work was far from easy,
and 96 dam workers were
killed in accidents. The men
had specific duties: Powder
Monkeys detonated
dynamite, while Puddlers
spread fresh concrete. High
Scalers probably had the
most dangerous job—they
climbed down the cliffs on
ropes to remove rocks.

34

Big blocks
The dam workers built wooden
formwork to cast more than
200 huge blocks of reinforced
concrete. These joined like giant
building bricks to form the dam.
They were stuck together with a
strong cement and water paste.

“

I came, I saw, and
I was conquered, as
everyone would be
who sees for the
first time this great
feat of mankind
U.S. President Franklin
D. Roosevelt, 1935

Taming the river
Upstream, the Colorado River (right)
is still wild and unpredictable. In
Boulder, the dam has blocked its flow
to create a huge man-made reservoir,
called Lake Mead (below). To build
the dam, workers had to divert the
river away from the site, by building
temporary dams and blasting tunnels
through the canyon rocks.

”

A new landscape
Almost every year, the Colorado River
had flooded in the spring, and then slowed
to a trickle during the summer months.
Farmers struggled to water crops, and
much of the area was a desert wasteland.
Hoover Dam transformed the landscape
around Boulder. It also now provides a
steady water supply to four states and
electricity to 1.3 million people.

Producing power
The hydroelectric power plant
sits at the dam’s base. Water
gushing through tunnels
from Lake Mead turns
massive turbine wheels
180 times per minute.
These connect via shafts
(pictured) to 17 electricity
generators. Each can
supply enough electricity
for 100,000 homes.

A huge attraction
The curved Hoover Dam is an
impressive 660 ft (200 m) wide and
730 ft (220 m) high and attracts more
than seven million tourists per year.
Half-buried deep underwater, the
base is so thick that the concrete
will probably continue to cure
(harden) for hundreds of years.

35

1973

Lids are usually made
from a different type
of plastic and often
cannot be recycled

NATHANIEL WYETH

Much lighter than glass,
and virtually unbreakable,
plastic bottles were obviously
a very good idea. But making
one for carbonated drinks was
surprisingly difficult. The bottles
that Nathaniel Wyeth designed
were first used for Pepsi Cola in
the 1970s. We now use them for
all types of things, such as peanut
butter and makeup. Unlike
most plastics, polyethylene
terephthalate (PET) can be
recycled, so it is becoming
more and more popular.

In Africa, some people make
their water safe to drink
using only PET bottles and
strong sunlight

An inquisitive man
Wyeth worked as an engineer for
the American company DuPont.
One day at work, his colleague
told him that plastic bottles were
useless for carbonated drinks.
That night, Wyeth filled one with
ginger ale and put it in the fridge.
The next day, the swollen bottle
was wedged in—it was too weak
to cope with the pressure. He
decided to make a stronger one.

BRIGHT SPARKS

Belgian chemist Leo Baekeland made the first synthetic
plastic, called Bakelite, in 1907, which became fashionable
in the 1920s for lamps, phones, and jewelry. PET, a type of
polyester, was developed in 1941.

PET bottles
36

Most water
bottles are now
made with PET

Ridges make bottles
stronger, so they can be
thinner and use less plastic

Hiding in the mold
Plastic molecules are long, thin chains.
Wyeth’s idea was to stretch these to line
them up—a technique that made nylon
thread stronger. Using air jets, he stretched
hot plastic inside different shaped molds.
After thousands of shapeless blobs, he
found one mold empty. Then, looking
closer at the sides of the mold, he
spotted his first plastic bottle.

Unlike this modern PET bottle,
early PET bottles had round
bottoms, so they could not stand
up without separate plastic bases

Recycling PET
PET comes from oil and takes
centuries to degrade, but Wyeth did
not really consider its environmental
impact. Luckily, it is easy to recycle.
The first recycled bottle became a new
Pepsi bottle base in 1977. PET is now
the world’s most recycled plastic.

The plastic is thicker
at the top, as it needs
to be more rigid

PET is usually clear,
but it can be colored
to bottle light-sensitive
liquids, such as beer
As well as the recycling logo, PET
bottles are stamped with “PET” or
“PETE” and the number “1”

Piles of old plastic
PET recycling starts with sorting and
squashing bottles into huge bales. These are
sent to a recycling plant, where machines
grind them into tiny flakes. After washing,
the flakes are sold on to plastics factories.

Recycling saves lots of
energy, but most PET
bottles are still buried

The perfect plastic
Wyeth tested different plastics for his
bottle, finally settling on PET, which
was normally used to make synthetic
cloth and carpet. Strong, light, and
cheap, PET is also very impermeable
(leak-proof) to gases. This keeps the
carbonated drinks inside very fizzy.
Although PET is cheap,
90 percent of the cost
of bottled water is the
cost of the bottle

Thousand uses
A surprising number of everyday things can
be made from PET bottles. Most are turned
into polyester fibers for carpets and fleece
material. But we also make them into shoes,
belts, bags, toys, ropes, containers, car parts,
and, increasingly, new bottles.

SEE ALSO Tin can 30 · Nylon 50

37

38

Stainless steel
People have been making
steel for thousands of years.
In 1821, French mining
engineer Pierre Berthier
noticed that adding
chromium metal made steel
more resistant to chemical
attack. But for years,
scientists were not able to
produce steel with enough
chromium to make it
stainless steel.

Chrysler Building,
New York, U.S.A.

Stainless steel makes
the building one of
New York’s most
stunning skyscrapers

Stainless steel is strong
and can withstand
wind and rain

When stainless steel is
damaged, it does not
rust because chromium
reacts with air to form
a protective scar

The architect of the
Chrysler Building had
the 180 ft (55 m) finial
(tip) added to make
sure that it would be
the tallest building in
New York City

Storage and transportation
Stainless steel tanks do not develop leaks,
even when they contain very corrosive
(damaging) chemicals. So we use stainless
steel to carry fuel, distil alcoholic drinks,
and even carry household garbage.

Surgical instruments
Doctors use stainless steel instruments
in surgical operations. Despite being
repeatedly sterilized (boiled to kill germs),
they do not rust. They are also resistant
to the chemicals in blood.

Most of us come across
stainless steel many
times each day—as nuts
and bolts, exhaust pipes,
saucepans, and even
kitchen sinks. As well
as being long-lasting,
it is also hygenic.

Stainless steel uses
HARRY BREARLEY

BRIGHT SPARKS

Rust-free silverware
Living among the steel factories of
Sheffield in the U.K., Brearley immediately
saw the potential of his “rust-less steel”
in the local silverware industry. In 1914,
factories started making knives from
stainless steel. During World War I, it
was used in the engines of fighter planes.

Englishman Harry Brearley was trying
to develop a type of steel for rifle barrels that
wouldn’t wear out quickly when bullets were fired.
To his amazement, among his many different steel
samples was one that did not rust. It even resisted
chemical attack from lemon juice and other acids.
Unlike other steels, stainless steel lasts in most
environments without having to be treated,
painted, or renovated. It has revolutionized most
modern industries, including food, medicine,
and transportation.

1913

SEE ALSO Portland cement 32

39

Carbon is the black
mineral found in coal,
which can also form
diamonds

The main ingredient
is iron, which is soft
and rusts easily

Chromium is very hard
but also brittle (breakable)
and can be poisonous

What is stainless steel?
Steel is an alloy (mixture) of iron with other
substances. To be stainless, it must be at least
half iron and at least one-tenth chromium,
with a tiny amount of carbon. Other metals,
such as nickel, can also be added.

Builders attached each
piece of stainless steel
cladding separately

Built in 1930 for the
Chrysler motor company,
the design was based on
parts of cars, including
hubcaps (wheel covers)

Stainless steel looks
much lighter in color
on sunny days, as it
reflects a lot of light

Claiming credit
Brearley is usually credited with the
invention, but other scientists claimed
to have made stainless steel first. Fed up
with using rusty razor blades, American
Elwood Haynes may have made one type
of stainless steel in 1911. There are other
claims from the U.S.A., and also from
Germany, Poland, and Sweden.

1830

When the contacts
touched, electricity passed
along the telegraph wire

JOSEPH HENRY

Operators tapped the
key quickly or slowly to
produce Morse code
The key acted like
a switch in a large
electrical circuit with
the telegraph receiver

The spring lifted
the key to break the
electrical circuit

Thousands of years ago, people
sent signals using drums, smoke, and
even pigeons. In the early 1800s, sending
a letter was still the easiest way to contact
someone far away. But telegraphs enabled
people to send messages long distance
along wires, with almost no delay.
Kick-starting electronic communication,
they paved the way for telephones,
cell phones and even instant messaging.

The receiver changed
the key’s electrical
signals into dots and
dashes on paper tape

Coils of wire
wrapped around
iron formed the
electromagnets

BRIGHT SPARKS
French inventor and
engineer Claude Chappe
devised the first nonelectric
telegraph network in 1794.
It crossed France and even
branched into other
countries. Relay towers
with armlike pointers
spelled out messages
in semaphore code (a
flag-based alphabet). These
were viewed by telescope
from the next tower.

Telegraph
40

Paving the way
In 1830, American scientist Joseph Henry sent an
electric current along more than 1 mile (1.6 km) of wire
to strike a bell. His receiving device used an electromagnet.
Many inventors then began designing telegraphs based on
electromagnets, with varying success. In the U.K., railroads
and post offices used telegraphs made by two British
inventors, William Cooke and Charles Wheatstone.

Morse and Vail
In America, Samuel Morse was successful in improving Henry’s
device. Morse abandoned a career as a painter to develop a practical
electric telegraph. In 1836, young engineer Alfred Vail saw Morse’s
crude device and offered to help improve it. They became partners,
with Vail developing the working Morse telegraph seen here.

A light metal arm moved
down and up as the coils
became magnetized and
demagnetized

Simply clever
The Morse telegraph caught on, mainly because it was
simple. It used just one telegraph wire to send messages,
so the code was crucial. Using short and long electrical
signals—dots and dashes—to make letters, Morse and
Vail’s code became the standard language of longdistance communication.

The other end of the arm rose
to make small dents in the paper
tape that fed through rollers

The most famous message
in Morse code is the
international distress
signal, SOS (... ___ ...)
The tape came out
here, embossed with
Morse code

The clockwork
mechanism kept
the tape moving
steadily

Telegraph wires being laid
across the Atlantic Ocean
by the S.S. Great Eastern

Telegraph wires carrying
Morse signals connected
to the coils of wire

Wiring the world
Built in 1844, Morse’s first telegraph line
ran between Washington, D.C. and Baltimore,
Maryland. Twenty years later, telegraph lines spanned
America and Europe and were soon to cross the Atlantic
Ocean. Even after the telephone was invented, the telegraph
business thrived for decades. The last telegram was sent in 2006.

SEE ALSO Cell phone 140

41

Who invented
the telephone?
Scottish scientist Alexander Graham Bell
is famous for inventing the telephone. But he was
not the first person to transmit voices along wires.
Nor was his telephone perfect—other scientists
helped improve it. Many inventors also claimed to
have invented the telephone before Bell, and some
nearly beat him to receiving the recognition for
this incredible device.
In first place
In 1874, Bell received funding to
develop a telegraph that could send
many messages down the same wire.
But Bell and his assistant, Thomas
Watson, also experimented with a
talking telegraph. Bell applied for a
U.S. patent for this on February 14,
1876. Three days after being given the
sole right to make and sell telephones,
he finally got the invention to work.
Bell fought more than 600 lawsuits to
defend his patent—the most valuable
ever issued. But he won every case.

“

I then shouted
into M [the
mouthpiece],
‘Mr. Watson, come
here, I want
to see you’

”

Alexander Graham Bell,
March 10, 1876

42

Alexander
Graham Bell
Born in Scotland in
1847 to a deaf mother,
Bell emigrated to Canada
before settling in the
U.S.A., where he taught
deaf children to speak
while investigating sound
and electricity. A prolific
inventor, he is shown here
with the telephone sketch
he drew in 1876.

Bell’s telephone
After forming the Bell
Telephone Company in
July 1877, Bell gave
lectures to promote his
invention. By the end of
the year, he had sold
3,000 telephones. He
used the receiver pictured
here to show Queen
Victoria of England how
the device worked.

The outsider
Antonio Meucci beat Bell to the patent office by five years.
But he could only afford temporary arrangements to
prevent others from patenting the telephone. He stopped
buying these in 1874—the year that his laboratory,
which he shared with Bell, claimed to lose his telephone
prototypes (working models). In 2002, the U.S. government
recognized Meucci’s work in the invention of the telephone.

Antonio Meucci
Meucci was an Italian inventor who moved to the U.S.A. in 1850.
His wife suffered from crippling rheumatism, and in 1857 he
built a telephone to talk to her from his basement laboratory.

A photo finish
Among the scientists fighting Bell’s patent in
court was Elisha Gray. He also took a design
to the patent office on February 14, 1876 and
accused Bell of stealing his ideas to make a
working receiver. Most people believe that Bell
beat Gray to the patent office by a few hours.
Yet a patent officer signed a legal document
saying that he had been bribed to award Bell
the patent—and that he even showed Gray’s
paperwork to Bell. Bell later denied that these
events happened.

Elisha Gray
Elisha Gray was born in Ohio in 1835.
He was a carpenter and blacksmith, before
setting up an electrical company in 1872.
He lost a long legal battle with Bell over
his telephone design (above) but held 70
patents, including one for a fax machine.

43

1989
TIM BERNERS-LEE

Tim Berners-Lee’s colleagues
at the European organization for nuclear
research (CERN) worked in many countries
on different computer systems. He
developed the World Wide Web to help
them share scientific information. Now
one quarter of the world’s population
can access billions of web pages over the
Internet—a network of linked computers.
This has completely transformed business,
culture, politics, shopping, and even the
way that we socialize.

The Internet network
CERN first used the web in 1991. But its
network also linked to other institutes, via a
network called the Internet. Soon, others
connected to the Internet were setting up
web servers. In 1993, CERN made its web
development tools freely available. Six
months later, there were 200 web servers,
and the Internet itself had begun to grow.

Berners-Lee
worked on a black
and white screen

Each page has its own
address, called a uniform
resource locator (URL)

A vague but exciting plan
In 1989, aged 24, Berners-Lee proposed that
information stored on central “web servers”
could be browsed by people on networked
(linked) computers using the simple point and
click system, called Hypertext. Writing “vague The first web browsers
were also editors, so
but exciting” on the proposal, his boss agreed
people could make
their own web pages
to the project. Sitting at this NeXT computer,
Berners-Lee put his ideas into practice. He
developed HTML (Hypertext Markup
Language) for writing web pages, HTTP
(Hypertext Transfer Protocol), which is how
servers and browsers talk to each other,
and the very first browsing program,
simply called WorldWideWeb.
Pointing and clicking on
a hyperlink directed the
browser to another web
page address

The average Internet user
visits more than a thousand
web pages every month
NeXT computer

World Wide Web
44

Easy browsers
The first web browsers were
black and white and only
worked on NeXT computers,
but other versions were soon
developed. Mosaic was the
first to become popular with
the general public. It was very
slow, but it already had sound,
video, and bookmarks.

TOMORROW’S WORLD
Experts think we will
soon be able to ask
the web questions like,
“Where can I get some
lunch?” Knowing about
us, and where we are,
it could then point us
toward a meal.

How the web has changed us
By making some things much easier,
the web quickly changed people’s
habits. Many with Internet access
would now struggle to do without.

Known as the Cube, this
NeXT computer was the
world’s first web server

The Cube once
stored all the pages
and files on the
World Wide Web

Buying things
Online we can usually find exactly what we
want to buy, at the best price. Without it, we
can only buy what nearby shops are selling.

Computers linked
via telephone wires
or cables could
browse the web

A sticker asked
people not to turn
off the computer—
if they did, no one
could access the web

Finding things out
We all used to depend on asking each other
or looking in books for answers. Now web
pages cover almost every topic imaginable.

The NeXT
computer was
powerful but
expensive

A new world
The early web was for sharing information. But with the
launch of Amazon.com in 1995, it also became a place to do
business. Entire industries had to adapt to this. So even before
broadband, mobile Internet, and countless web innovations
like blogging, our world had already changed forever.

Rather than a fixed hard
drive, the computer had
removable optical disks

Networking with friends
Over the Internet, we can chat with
friends, wherever they are, and also
show them photos.

SEE ALSO Microprocessor 98

45

1957
GORDON GOULD

Based on a theory by physicist
Albert Einstein, the invention of the
laser was initially described as a solution
looking for a problem. But people quickly
found uses for its intense, narrow beam of
light. Today lasers penetrate almost every
aspect of life, from scanning bar codes to
treating cancers, guiding missiles, and
even replacing hair.

Laser light is both
bright and sharp

A laser produces light waves
with the same wavelength,
so they are a single color

Masers and lasers
In 1954, Charles Townes built a maser.
This used stimulated emission to amplify
microwaves—similar to light waves, but with
longer wavelengths. Adapting it for light waves
was far from simple. In 1957, Townes’ student
Gordon Gould started making a laser. But
failing to understand the patent process, he
did not protect his invention and his work
was exploited by others.

To trace the Moon’s path,
scientists fire laser beams
at mirrors that sit on the
Moon’s surface

Computer programmes
can analyze a DJ’s music and
produce laser effects to go with it

The peaks and
troughs of laser light
waves are in step

Theory of a genius
We usually think of light as waves. Ordinary
white light is a mixture of colored light waves,
each one with a different wavelength. These are
emitted (sent out) at random intervals in all directions.
In 1917, Einstein theorized about making a much
stronger light, using what he called stimulated
emission. This would consist of waves with exactly
the same wavelength that were perfectly in step,
and all traveled in the same direction.

Laser
46

Moving mirrors
make fast flashing
laser beams look
very dramatic

The beams only shine
at the audience briefly,
as they can damage
people’s eyes

Laser machines often
have two or three
lasers, for different
colored beams

Lasers big and small

Lone operator
There was a race to build a laser, with large research
teams trying to create laser beams from different
materials. However, it was Theodore Maiman,
operating alone, who made the first working
laser in 1964, using a ruby crystal.

Maiman’s laser used a ruby, but many
other substances can also be used.
Some lasers are delicate and precise,
while others are extremely powerful.

Light drilling
Many dentists now use lasers rather than
drills to whiten teeth, reshape gums, and
remove decay. Surgeons also use lasers for
delicate operations on the eyes and brain.

COOL SCIENCE
Photons of
light bounce
off the mirror
at the back

The flash tube
coils around the
ruby crystal

The semitransparent mirror
reflects back most of the light,
but lets some pass through

Light industry
Focused laser light can cut through most
materials, including thick sheets of metal.
Lasers can cut awkward shapes into delicate
materials, and they never need sharpening.

Strong red
laser beam
Bouncing photons
stimulate the release of
other photons, so the
light gets stronger

Aluminum
reflecting cylinder

White light from the ruby laser’s flash tube gives the ruby’s atoms extra
energy. Some release this as photons (small packets) of red light. When
photons meet other high-energy atoms, they make them release energy,
too, as photons that are in step. As photons bounce between the two
mirrors, the new laser beam strengthens and finally emerges through
the semitransparent end.

Earth health check
Scientists use lasers to study the atmosphere
and monitor greenhouse gases. Lasers are
also used to monitor pollution in rivers.

SEE ALSO Bar code 128

47

1967
JAMES FERGASON

The development of liquid crystal
displays (LCDs) has been central to our
increasingly digital lifestyle. These slim
panels are used in most modern electronic
gadgets. Many people contributed to the
development of LCD technology. But the
breakthrough that led to practical screens
came in 1967, when American inventor
James Fergason discovered a type of
liquid crystal that could block or let
through polarized light. Modern LCDs
can display images, text, and video—and
they are rapidly becoming smaller
and more sophisticated.

Glass sandwich
LCD screens are layers of liquid crystal sandwiched between
sheets of special glass, which—like sunglasses—polarizes
(filters) light. They are thinner, lighter, and use less energy
than the bulky cathode ray tubes of old-style screens.

The liquid crystals
are in segments,
each with its own
electricity supply

Reflected light
makes the display
appear gray

BRIGHT SPARKS

Electricity stops the crystals
from letting light through the
glass, so these areas are dark

Liquid crystals were discovered in 1888, but few
scientists looked into their uses. Interest exploded in 1963,
when George Heilmeier (above) and Richard Williams
suggested using them for displays. LCD screens appeared
four years later.

LCD
48

Low-energy display
A black and gray LCD does not need a backlight,
making it perfect for low-energy, battery-powered
devices. Instead, surrounding light simply bounces
off a mirror at the back of the display.

Liquid crystals are neither solid nor
liquid; they exist in a state of
matter between the two

COOL SCIENCE
Vertical
polarizing filter

Liquid crystal
twists light

A backlight makes
color displays bright
enough for us to see
tones and details

Color filter

Glass
The number of pixels
in a display is known
as its resolution

Electricity
applied

Horizontal
polarizing filter

Display

Touch-sensitive LCD screens
are handy for everyone, but
they also make it easier for
people with language
difficulties to communicate

Light enters an LCD
display and is polarized
(to orient the rays in
one direction) by a
filter. When electricity is
applied, the liquid crystals
line up in a different
direction, blocking light
from passing through a
pixel and making these
sections appear dark.

Pixel pictures
More complex displays split the
liquid crystals into millions of tiny
elements called pixels. The more
pixels a screen has, the more detailed
its images. A computer screen can
have more than one million pixels.

Each pixel (made
up of red, blue, and
green) can display
more than 16 million
different colors

Color filters
cover the liquid
crystals in
each subpixel

Each subpixel has a
variable electricity
supply with 256
brightness levels

Creating colors
Pixels are split into red, blue, and green subpixels, with
liquid crystals controlling the brightness of each. They
are so small that our brains see the combination of reds,
blues, and greens as single colors.

SEE ALSO Television 88 · Digital camera 112 · GPS 190 · Sunglasses 236

49

1935
DUPONT AND
WALLACE CAROTHERS

In 1935, a patent was granted to the
American chemical company DuPont
for a new material called nylon. Products
made from nylon reached stores in
1938. They were an instant hit with
customers. At first, nylon fibers were
used in toothbrushes. They also
replaced silk in stockings, which
became known as nylons. Today,
nylon is used in a variety of products
and textiles. As well as nylon fibers,
solid nylon is used to make plastic
products, including plastic pipes
and some mechanical parts that
used to be made from metal.
Why is nylon so useful?
Nylon is widely used because it is strong,
tough, long-lasting, lightweight, easy to wash,
resists scratches, and is not damaged by oil
or a wide variety of chemicals. It can also
be easily dyed different colors.

COOL SCIENCE

Nylon is a polymer. A polymer is a long chain of units
made of groups of atoms. Nylon is made in a laboratory,
but there are polymers in nature, too. Cellulose, found in
the cell walls of plants, and natural rubber are polymers.

Nylon
50

The bottom of the
balloon is made of
fireproof material
because nylon is
sensitive to heat

The downside of nylon
Nylon has some disadvantages.
If it gets too hot, it melts and
burns. When it burns, it gives
off poisonous fumes (gases).
Once it is made, it is difficult to
dispose of. Unlike natural fibers,
such as cotton and wool, nylon
does not rot in the ground when
it is thrown away.

Nylon is made from
petroleum—it was
developed to be a
substitute for silk,
a more expensive
material to make

The balloon
fabric is made
from nylon
panels stitched
together

The nylon fabric is
coated with chemicals
to make it more airtight
and waterproof

Nylon balloons
Most hot-air balloons are made
from nylon. It was first chosen
for this job because it had
already proved to be a very good
material for making parachutes.
A type of fabric called ripstop
nylon is used. Extra threads are
woven into the material to stop
tears from spreading.

The very first parachute
jump using a nylon parachute
was made in 1942

A versatile material
Nylon can be made into different
forms, making it a good material
for products found in industry,
sports, and the home.

Pipes
Nylon can be molded and formed into
different shapes. Nylon pipes and hoses are
used in car engines. Water and drainage
pipes are also often made of nylon.

Rope
Nylon is used to make strong and flexible
ropes. In fact, nylon ropes are the strongest
type in common use. They are used in
mountaineering and to pull heavy loads.

Woven and stitched
Nylon fibers are used in all types of products
that are woven or stitched together, including
clothing, carpets, upholstery, and tents.

SEE ALSO PET bottles 36 · Umbrella 214

51

Wallace Carothers

“

The story of nylon began
when DuPont opened a new
research center in the 1920s. They
chose a brilliant young scholar and
chemist, Wallace Carothers, to run
it. Carothers was born in Iowa on
April 27, 1896. After obtaining a
science degree in 1920, he earned a
doctorate at the University of Illinois.
Carothers went to work at Harvard
University in 1926, and two years
later he moved to DuPont.
Leaving Harvard
When Carothers was offered the chance
to run his own laboratory at DuPont,
at first he was unsure of whether
or not to leave Harvard. He would
have more research assistants
of higher quality at DuPont,
but he might be freer
to follow the research
that most interested him
at Harvard. DuPont
reassured him that he
would be given all the
support he needed
to carry out his research.
They also offered him
nearly twice as much
money as he was
earning at Harvard.

Wallace Carothers
Carothers and his team of
scientists at DuPont made new
materials by combining different
chemicals. They tried scores of
combinations, searching for one that
would produce a successful new material.

52

Nylon can be
fashioned into
filaments as strong
as steel, as fine
as a spider’s
web, yet more
elastic than. . .
natural fibers
DuPont Vice-President
Charles Stine, 1938

”

An unhappy life
Sadly, Carothers did not live to see
the great success of the materials that he
created. He rarely went out and hated
the public speaking that he had to do as
part of his work. He also had bouts of
depression. In 1936, Carothers married
Helen Sweetman, another DuPont worker,
but his depression continued and he spent
some time in a hospital. On April 29, 1937,
at the age of 41, Carothers killed himself
by taking poison—one year before the first
nylon products went on sale to the public.

Neoprene
Nylon wasn’t the first new
material to be made in
Carothers’ laboratory at
DuPont. In 1930, it developed
neoprene, the first successful
mass-produced synthetic
rubber. Wetsuits worn by
divers are made of neoprene.

First products
The first nylon product that people could buy
was a toothbrush with nylon bristles. Until
then, bristles had been made of animal hair.

Mass production
Nylon is ideal for making thousands
of copies of the same product by
forcing liquid nylon into molds.
This DuPont worker is surrounded
by 10,000 nylon combs, the number
that one worker could make in a
single day in the 1950s.

53

Dynamite

54
Scientists are developing
new explosives that will
make firework displays
even more spectacular.
Mixing chemicals in
miniscule quantities—
literally a few molecules
at a time—makes them
more powerful, so even
more explosive.

TOMORROW’S WORLD

Killer chemical
Italian chemist Ascanio Sobrero first made the liquid
nitroglycerin—dynamite’s explosive ingredient—in
1846. It was much more powerful than gunpowder, but
deadly to handle. Even the tiniest knock could make it
explode. It caused many fatal accidents, including one
that killed Nobel’s younger brother, Emil.

Dynamite was the first powerful
explosive that was safe to handle.
It transformed construction, mining, and
quarrying, blasting a path into the 1900s.
We use explosives to build railroads, roads,
and tunnels. We blast through rocks to build
dams and crack them open to extract coal.
Alfred Nobel’s discovery also ignited research
into more powerful explosives. These help
us free up even more of Earth’s resources—
the rocks and minerals used to make cars,
computers, cell phones, and even medicines.
Invented in 1878,
blasting boxes used
electricity to set off a
blasting cap

Pushing the plunger
sent a powerful
electric current
down a wire

Health and safety
Nobel developed devices called
blasting caps. These could be used
to detonate (trigger) nitroglycerin
explosions from a distance. But
he also discovered that mixing
nitroglycerin with kieselguhr (a
chalky sand) made it much safer.
He called this substance dynamite.

1866

ALFRED NOBEL

SEE ALSO Hoover Dam 34

55

Born in Sweden in 1933,
Nobel grew up in Russia,
where his father made
land mines for the Czar.
He learned to speak five
languages and developed
wide interests. Although
chemistry was his
greatest passion, Nobel
also wrote poetry in his
spare time.

Alfred Nobel

The fuse allows explosions to
be set off from a distance—
this type burns

The fuse triggers a small
explosion in a blasting cap
attached to its end

The shock from the exploding
blasting cap makes the
dynamite explode

Firefighters use dynamite and
other explosives to put out
fires in oil wells

An inventive man
Nobel started his dangerous
experiments with explosives
in 1860, continuing them
long after he invented
dynamite. When he
died, aged 63, he
held 355 patents—
for inventions such as
synthetic rubber as well
as for other explosives.
Shown here is his
laboratory in Sweden.

Dynamite does not have to
contain kieselguhr—sawdust
and other absorbent materials
can also be used

Nobel Prize
Dynamite made Nobel
a wealthy man, but he
was sad that people
used his inventions
for war. In his will,
Nobel left his
fortune to set up the
Nobel Prize. Since
1901, this has been
awarded every year
for work that most
benefits humankind.

Detonating dynamite
Dynamite was so stable that it could be
dropped, hit, or burned without exploding.
But it still exploded powerfully when
detonated by a blasting cap. Demand for
dynamite grew quickly, and Nobel eventually
owned 90 dynamite factories in 20 countries.

Dynamite can be
shaped into tubes and
safely packed in paper

Great Gizmos

A single amazing
invention, like the
clock or the printing press,
can change people’s lives all
over the world. Often, great
gizmos like these go through
many versions over the years,
getting better and better all the time.

1860
ÉTIENNE LENOIR

Engines are machines that burn fuel
to make things move. The first successful
engines were all steam engines, which use
steam from a boiler to move a piston in a
cylinder. In internal combustion engines, the
fuel is burned inside the cylinder. This makes
them lighter and more efficient than steam
engines, so they quickly replaced steam
engines in machinery and vehicles.
Lenoir’s gas engine
In 1860, Belgian engineer Étienne Lenoir
built the first successful internal combustion
engine (right). It was also the first to be built
in large numbers. Lenoir’s engine mixed
gas with air inside the cylinder and was
ignited (set alight) with a spark. The gas
exploded, thrusting out the piston, which
then turned the wheel.

Once this flywheel is
turning, its weight
makes it difficult to
stop, helping the
engine run smoothly

Tiny explosions
There are two types of internal combustion
engines: those in cars and motorcycles are
intermittent, which means that fuel burns in
short bursts. Jet planes and rockets have engines
in which the fuel burns constantly.

Modern engines are more
than 100 times as powerful
as Lenoir’s engine

The driving wheel
turns a belt that
powers another
machine

BRIGHT SPARKS

In 1823, Samuel Brown
patented a two-cylinder,
gas-powered internal
combustion engine, and in
1825 he used it to drive a
vehicle, though it wasn’t
very successful. It was too
similar to a steam engine
to work well.

Engine
58

The piston pushes
these rods to turn
the flywheel

The engine evolves

TOMORROW’S WORLD
Tiny internal combustion engines
can be used instead of batteries
to produce electricity to power
equipment such as computers.
(Batteries need to be recharged
about five times as often as these
engines need to be refueled.) They
are made of steel, but the scientists
who made them want to use silicon
to build much smaller versions,
which will be the size of pinheads.
From fuel to fumes
Internal combustion engines convert the energy that is
contained in fuel into other forms of energy, including
motion and heat. They produce pollutants, including
gases and tiny particles, during the process. These
waste products are called exhaust.

This rod connects
the governor to an
automatic control tap

This pipe supplies
gas to the engine

Gas to liquid
Nikolas Otto made an improved version
of Lenoir’s gas-fueled engine. Then, in 1885,
Daimler modified it to run on liquid fuel,
and used it in the world’s first motorcycle.

Exhaust fumes
leave through
this pipe

The governor controls
the speed of the engine

Air intake

Over the years, engineers have
worked hard to build engines
that are reliable, quiet, light, run
smoothly, and use fuel efficiently.

The cylinder
contains the
piston

Speed machine
The Harley-Davidson company has been
making motorcycles for more than a century.
This one is from 1942—by then, engines
were extremely efficient and powerful.

Built for sport
Today, supersport bikes perform well
because they have “high revving” engines,
which means their components move very
quickly, producing a great deal of power.

SEE ALSO Ford Model T 148 · Helicopter 160 · Electric car 172

59

Elevators

60

Walls and ceiling are
made of toughened glass
that is treated to keep
out the Sun’s heat

Clever machinery
Today’s elevators are
comfortable, fast, and safe.
Many are connected to
computer systems to ensure
that they are in the right place
at the right time. This is done
by keeping elevators close to
busy floors when not in use,
and making sure that they
stop more often on downward
journeys when it’s time for
people to leave the building.

The first elevators were
invented thousands of years
ago in ancient Greece. For a long
time they were not a very safe way
to travel, and it was only after
1852—when Elisha Otis designed
and demonstrated one that was
equipped with a safety device—
that people began to trust them.
Without safe elevators, there could
be no skyscrapers, and modern
cities would look very different.
INSIDE
SAFETY
BRAKE

STAGE 2: IF SPEED IS TOO HIGH

Arms locked
into ratchet

Wheel can no
longer turn

STAGE 1: AT SAFE SPEED

Arm
Ratchet

Arm

Four sets of rollers
engage with a pair
of rails that run up
the side of the building

Elevators are equipped with very reliable safety systems. If
the elevator starts to fall, its cable spins the wheel inside the
safety brake faster than usual, and the two arms inside the
brake swing outward and interlock with a ratchet. This prevents
the wheel from turning, bringing the elevator to a halt.

Shock
absorber

Counterweight
balances weight
of passenger car

Passenger
car

Computerized
controller

COOL SCIENCE

1852
ELISHA OTIS

SEE ALSO GPS 190

61

One day, it may be possible
to travel into space in an
elevator! There are already
thousands of satellites in
orbit around our planet.
Some orbit at the same
rate that Earth turns, which
means that they always
remain above the same
location. In theory, an
elevator could take people
up to satellites, as shown in
this artist’s impression.

TOMORROW’S WORLD

Elevators everywhere
It’s not just people who use elevators:
they are often used for moving goods
around, and some multistory parking
lots have vehicle elevators, too. Aircraft
carriers have huge versions, each large
enough to hold two jet planes and able
to lift more than 150,000 lb (70,000 kg).
Special types of elevators, called stair
lifts, can also be fitted into the homes
of people who find it difficult to
walk up stairs.

The world’s fastest elevators are
in the Burj Khalifa skyscraper in
Dubai, United Arab Emirates—they
travel at 40 mph (64 km/h)

Cool views
Occasionally, skyscrapers
have external elevators that
travel up and down the outside
of their walls. This saves space
inside the building and gives
people amazing views as they
travel. As these elevators are
exposed to the weather, they
have to be fitted with special
heating and cooling units.

Ventilation, as well as
heating and cooling
systems, automatically
keep conditions
comfortable inside
the elevator

Metal rails provide
extra safety

Elisha Otis
Many cities are dominated by huge
and beautiful skyscrapers and famous
landmarks. Skyscrapers allow huge cities to be
built using only small amounts of land, and they
provide safe, sheltered, and comfortable places
for people to live and work. But without
Elisha Otis’s big idea, we would not have
these incredible buildings today.
Global safety
American inventor Elisha Otis installed his
first passenger-carrying safety elevator in a
New York department store in 1857 and kept
improving his invention until his death in
1861. His sons, Charles and Norton, then
started the Otis Brothers Company, and by
1873 more than 2,000 Otis elevators had
been installed. Their use in famous buildings
helped make them popular, and there are
now 1.7 million in use all over the world.
Elisha Otis
In 1853, Otis staged a dramatic demonstration
of his safety elevator in an attempt to gain public
confidence. He cut the rope of an open elevator.
Luckily, his safety system worked and led to
the development of high-rise buildings.

Eiffel Tower

Statue of Liberty

Otis elevators were installed in the
curved legs of the Eiffel Tower in France.
Completed in 1889, it was the world’s
tallest structure until 1930. It is still the
tallest in Paris and is one of the most
recognizable buildings in the world.

In 1886, the Statue of Liberty
was given to the U.S.A. by the
people of France. It has 324 steps,
but in the early 1900s an Otis
elevator was installed, making
going to the top a lot easier!

62

The sky’s the limit
What people call a skyscraper has
changed over the years. In the 1880s,
the Home Insurance Building in
Chicago, Illinois, seemed amazingly
high, but its 10 stories would not be
very impressive today. However, it
introduced the building technique
that, together with the elevator, is key
to skyscraper construction: it was built
using a metal “skeleton” of iron and
steel to support the weight of the
building rather than its external walls.
Later skyscrapers used all-steel frames.
Burj Khalifa
Dubai’s Burj Khalifa (which means “Khalifa Tower” in
Arabic) is the tallest structure in the world. Completed
in 2010, it is 2,717 ft (828 m) high and has 208 floors.
The building contains 57 Otis elevators. Two of these
are double-decked elevators (one cab mounted above the
other) that take people to the 124th floor observation deck.

“

A skyscraper is a boast
in glass and steel

”

Mason Cooley, American author

Milan Cathedral

Mori Tower

For centuries, the highest city
buildings were often cathedrals.
This one in Milan, Italy, was started
in 1386 but not finished until 1965!
In 1997, a new Otis elevator was
installed inside one of the 135 spires.

Opened in 2003, the Roppong Hills Mori
Tower is an important landmark in the
Japanese city of Tokyo. People can work,
shop, and play under one roof. There are
12 Otis elevators in this 54-storey building,
all of which are double-decked elevators.

63

1927
A compressor unit
transfers heat from the
refrigerator into the room

CHRISTIAN STEENSTRUP

Many people helped develop the
refrigerator, but they only became
really useful machines when people could
afford to buy them for their homes. The
price of the General Electric all-steel
model was what made it into a household
item. Chilling food slows down the growth
of bacteria that cause food poisoning, so
food in a refrigerator lasts longer before
going bad. It also means that less food is
wasted, people suffer fewer health
problems, and shopping no longer
has to be a daily chore.

Controls allow
the temperature
to be set

The icebox is the
coldest part of
the refrigerator

A cheaper chiller
Christian Steenstrup worked for the American company
General Electric, and designed the first affordable
refrigerator in 1927. At $525, it was still expensive, but it
cost half the price of its competitors. Just three years later,
it was by far the most popular refrigerator in the U.S.A.

BRIGHT SPARKS

Until the mid-1900s, people moved natural ice from
cold parts of the world to warmer areas and stored them
in underground “ice houses.” Chunks of ice from the ice
houses were used to cool “iceboxes,” which were like
unpowered refrigerators.

Refrigerator
64

GE monitor-top
refrigerator, 1927

COOL SCIENCE
Put to good use
Another advantage of the all-steel refrigerator
was that it didn’t have the strong smell of ammonia
that some other types had, so it could be kept in
the kitchen. Since then, refrigerators have become
common items—but they aren’t only used for food
storage in homes. They are vital in hospitals to
keep medicines cool, and every air-conditioner
unit contains one. Refrigerators that can cool to
below freezing point are called freezers and are
used to store food for even longer.

A coolant gas
circulates in coils,
absorbing heat
An expansion valve
converts liquid coolant
into cold gas
The condenser coil
releases heat from
the coolant
The motor drives
the compressor
Compressor

If you blow on wet skin, it
feels cold. This is because the
liquid water is changing into
vapor—and it is using heat
energy to do it. Refrigerators
work in the same way: inside
them liquid changes to gas,
cooling the interior. The
gas changes back to liquid
in pipes outside the unit,
releasing warmth into the air.

Purple cold areas

Green cool areas

Seeing heat
All objects send out infrared rays, which we
can sometimes feel as heat. Although we can’t
see these rays, special cameras can detect them
and make heat-pictures of things, like the inside
of this refrigerator. These heat pictures are
called thermograms—in this one, the hottest
objects are red and the coldest are purple.
It’s important that refrigerators do not have
hotspots, where food would go off, or cold spots,
where it might be damaged by being frozen.
A thermogram of the refrigerator could be
used to check for warm or cold spots.

The latch ensures that the
door closes tightly, so that
cool air does not escape

The single-door refrigerator
was the most popular model,
but there were models with
two doors—and even some
with three doors

A thick, insulated door
stops the refrigerator
from warming up

Red warm areas

A refrigerator warms the
room that it is in, and if you
open its door, the room will
soon become even warmer

Magnetic attraction
In the future, refrigerators may be cooled by using
magnetism. Some materials contain tiny structures
called magnetic domains, which form patterns when
a magnetic field is present. When the field is turned off,
the domains become jumbled, which cools the material
as part of the jumbling process. The cold material can
then be used to cool a refrigerator.
SEE ALSO Vaccination 18 · Tin can 30

65

1887
JAMES BLYTH AND
CHARLES BRUSH

Machines powered by wind have
been in existence for thousands of
years. Windmills have long been used to
grind grain into flour to make bread and
to pump water. Yet it was not until 1887
that the wind was first used to generate
electricity. A Scottish inventor James Blyth
used a horizontal windmill to generate
enough electricity to light his own house,
and, coincidentally, American inventor
Charles Brush built a similar machine
for his Ohio home. By the 1930s, there
were wind-powered generators all over
North America, mostly supplying
electricity to remote farms.

Generating interest
James Blyth realized how useful his invention
could be and offered to build a machine that
would provide enough power to light the streets
of his village. His neighbors, however, were not
so easily persuaded. They thought electricity
was the work of the devil and refused his offer.
Eventually, Blyth’s invention was put to good
use when wind-powered generators provided an
emergency electricity supply for his local hospital.

Turbines today
Today, electricity-producing wind machines are
called wind turbines. Each one produces only a
little electrical power, so hundreds are needed to
supply as much as a power plant. As a result,
they are often built in groups, called arrays or
wind farms. As the wind changes direction, the
tops of the turbines turn to face the wind.
Doubling the length of a wind
turbine’s blades produces not
just double, but four times as
much electricity—so the best
wind turbines are large ones

The world’s largest wind turbine
has a rotor 410 ft (125 m) across

Most wind turbines are
painted gray to blend in
with the color of the sky

A ladder allows
access to the nose
for maintenance

COOL SCIENCE
Gear wheels

Low-speed
shaft

High-speed shaft
Generator

Nose
Tower

Rotor
Electric cables
from generator

The blades of a wind
turbine turn only once per
second or two. Generators
use electromagnets to turn
motion into electrical
power. They only work well
at high turn speeds, so gear
wheels are used to “step
up” the rotation to around
20 turns per second.

Above the waves
The wind blows more strongly
out at sea, because there are no
hills, trees, or buildings to slow it
down. So, many wind farms are
built offshore, even though this
is much more complicated and
expensive than building them
on land. However, it does mean
that people are not bothered by
the noise that they make.

Wind turbine
66

Good or bad?
Wind turbines are often regarded
as one of the solutions to the energy
crisis: unlike fossil fuels, wind energy
will never run out. However, there are
fierce disagreements about whether
their benefits are worth the problems
that they cause.

The generator turns the
motion of the blades into
electricity. The turbine
shuts down automatically
at very high wind speeds
to avoid damage

Advantages of wind energy
Wind turbines occupy only small areas and
can share fields with crops or cattle. Unlike
power plants that burn coal or oil, they
make no waste gases, so they are considered
a source of “green” energy.

The wind turbine’s
tower is a huge steel
tube, up to 300 ft
(90 m) high

Disadvantages of wind energy
Some people think that wind turbines are
ugly and pose a threat to flocks of birds that
might fly into them. When turbines are in
remote places, it is expensive to transmit
the electricity that they make to the people
in towns and cities who will use it.

SEE ALSO Solar cell 92 · Helicopter 160

67

1821

Electromagnets hug the
rotating iron ring in the
middle of the machine
to intensify the magnetic
forces acting on it

MICHAEL FARADAY AND
ZÉNOBE GRAMME

Michael Faraday’s groundbreaking
work with magnets and electricity led
to simple electricity generators. The discovery by
Zénobe Gramme that generators could also be
used in reverse as electric motors gave people a
new source of power for industry. Before electric
motors were available, machines were powered
by steam, water, or animals. Today, electric
motors are used in a huge number of household
items and are essential for industry.
Faraday’s motor

In 1821, Faraday showed that electricity
and magnetism could produce motion
when he invented a simple electric motor.
Modern motors use electricity and
magnetism, too. A motor contains coils of
wire wound around pieces of iron. When
electricity flows through the coils, they
become magnets. These “electromagnets”
and other magnets push and pull each
other to turn the motor.

Two metal arms
transfer direct
current electricity to
the metal barrel

The barrel supplies
electricity to the wire coils,
alternating the direction of
the current so that the
motor keeps turning

TOMORROW’S WORLD

Gramme
machine

Tiny electric motors open up exciting new possibilities.
The prototype Proteus motors are just 2½ times the width
of a hair and small enough to travel through blood vessels.
Surgeons will equip them with cameras so that they can be
used to repair damage to the circulatory system.

The coils of wire are wrapped
around an iron ring that can rotate
freely between the electromagnets
above and below it

Electric motor
68

When electric currents flow
through the wire coils,
magnetic forces turn
the iron ring

Two electromagnets
connected by a frame
provide a north and
south pole

Reversal of fortune
In 1870, Zénobe Gramme built the first generator that
produced enough power for industry. The Gramme
generator, or Gramme machine, produced a
smooth, constant current. While he was
demonstrating it in 1873, his partner
mistakenly hooked two generators
together, so that one supplied electricity
to the other. To their surprise, the shaft
of the second generator turned—it had
become an electric motor.

The world’s largest
electric motor turns a
huge fan, which blows
wind faster than the
speed of sound
The rotating iron ring is
attached to a steel shaft,
which turns as electricity
flows through the coils

Driving the world
Almost every electrical object
with moving parts contains a motor,
from vibrating cell phones to large
industrial machines. Electric motors
can be as small or large, as the job
demands, and can be started and
stopped with the flick of a switch.

Alternating current
Most large machines in the home have
motors that can use alternating current
(AC )—a type of current that is supplied
to wall outlets and constantly changes
direction. In 1883, Nikola Tesla invented
another type of AC motor, which is used
to operate heavy machinery in factories.

As the shaft
rotates, it moves
any object that it
is connected to

When the machine is
used as a generator, this
shaft is turned by an
engine and the machine
produces electricity

Spark of genius
Despite being designed to generate
electricity, the Gramme machine was
a very important discovery in
the development of the
electric motor. In fact,
many motors used
today are still based
on Gramme’s machine.

Direct current motors
Batteries supply constant, direct current
(DC ), and many battery-powered gadgets,
such as electric toys, use DC motors fitted
with permanent magnets. We use another
type—the stepper motor—in complex
electronic equipment like computer disk
drives, where movement needs to be precisely
controlled. Laptops and other gadgets have
adapters that convert AC electricity into a
DC power supply to run these motors.

SEE ALSO Battery 96 · Steam locomotive 162

69

The father of
electricity
From luxury gadgets to
lifesaving machines, today’s
electrical equipment depends on
the discoveries made by the genius
known as the “Father of Electricity”—
Michael Faraday. His groundbreaking
inventions include the first electric
motor and a method of
generating electricity that
lies at the heart of all power
plants. Faraday’s ideas
inspired other scientists
to explore electricity and
magnetism, sparking a
golden age of invention
that changed the world.

Michael Faraday
Faraday, an English
Chemist, came from a poor
family and left school at 13.
In the 1800s, it was very
difficult for someone like him
to become successful. Yet
Faraday achieved so much
that, in 1858, Prince Albert
awarded him a house at
Hampton Court Palace,
in southern England.

Teaching science
Faraday loved to share his excitement
about science with everyone. In 1825,
he began to give entertaining Christmas
lectures for young people at the Royal
Institution in London, Engand. The
lectures continue today and are
shown on television.



Using electricity
In the early 1800s, electricity was
a laboratory novelty rather than a
practical source of energy. Faraday
changed this when, in 1821, he
showed that electromagnetic energy
could be used to produce motion—
creating the first electric motor. In
1831, he discovered that electricity
begins to flow in a conductor when
it is moved between the poles of a
magnet. Within weeks, he used
this idea to invent the electric
transformer and generator.
For the first time, electricity
could be produced without
a battery and in much
greater amounts.

Motor
Faraday was inspired by the discovery of
electromagnetism—the fact that a current
passing through a metal wire produces a
magnetic field around the wire. His simple
motor used this idea. He suspended a wire
in a small cup of mercury with a magnet
at the bottom (left). When a current was
passed through the wire, it swung around
the magnet in a circle. This was the first
time anyone had produced continuous
movement from electricity.

Transformer

Faraday made the first
transformer by coiling
two lengths of wire
around an iron ring

Transformers turn high voltages
into low ones and vice versa.
They are used in electrical gadgets,
and to change the high-voltage
electricity from power plants
into safer voltages for our homes.

Diary

Passing electricity
through one coil
made an electric
current flow briefly
in the other coil

Faraday researched many
other areas of chemistry and
physics. In 1822, he wrote in his
diary (above) “Convert magnetism
into electricity!” However, he was so
busy that almost 10 years passed
before he tried doing it.

Generator
Faraday’s generator uses magnets and motion to
generate electricity. The copper wheel is turned by
hand so that its rim passes between the poles of
a permanent magnet. This continually cuts the
magnetic force lines, causing an electric current to
flow in the copper. The current is led off through
a wire and today can power a small lightbulb.

71

1764
JAMES HARGREAVES

Moving the bar
stretched the yarn

The worker spun the
wheel with one hand and
the bar with the other

James Hargreaves never meant to
change the world—his invention, the
spinning jenny, was simply a machine that
made it quicker and cheaper to produce
yarn from the fluffy covering of cotton
plant seeds. But cheap yarn was bad news
for other yarn makers in the area, and they
smashed his machine. Hargreaves fled to
Nottingham, England, and continued
to work on automation, the process of
replacing human labor with machines.

“Jenny” was the name of Hargreaves’
daughter, who knocked over a
spinning wheel and gave
Hargreaves his big idea

These helped
twist together
the fibers

BRIGHT SPARKS

Some of the earliest spinning machines were spinning wheels,
and they were probably invented in India. Spinning wheels
were used to turn natural fibers, such as wool and cotton,
into a thread that could be woven or knitted into a textile.

Spinning jenny
72

Cottage industry
Before the invention of
the spinning jenny and other
textile machines, textiles were
made at home. This is known
as a cottage industry. Spinning
was mostly done by women,
while weaving—making
finished cloth—was generally
seen as men’s work.

Yarn was wound
around a row of
spinning spindles

Child labor
One of the reasons for the success of the spinning jenny
was that it could be operated by a child, unlike spinning
wheels, which were more difficult to use. Hargreaves
died in 1778, and by then more than 20,000 spinning
jennies were in use all over Great Britain.

Slow progress
The invention of the spinning
jenny was part of a slow process
of developing textile machines, in
which many inventors were involved.

These cords attach
the wheel to spindles
The worker
rotated the wheel
with this handle

Kay’s flying shuttle, 1733
John Kay’s flying shuttle, which was a
device for holding thread, speeded up the
process of weaving. Machines with these
shuttles were faster at making more fabric,
of greater width, and with fewer workers.

A row of bobbins held
the loose cotton fibers
in place, ready to be
fed through the bars
to the spindles

Time for change
The spinning jenny, and
other machines used to
make textiles, changed the
way in which people lived
and worked. Their use
sparked the time known as
the Industrial Revolution—
a period when large factories
were set up and people moved
from the country to towns. Its
effects spread from Europe and
throughout the world.

Although early spinning
jennies had sloping
wheels, later models
had upright ones, which
were more efficient

Arkwright’s water frame, 1768
Richard Arkwright’s invention was an
important improvement on the spinning
jenny. It made stronger cotton threads,
and was powered by a water mill.

Crompton’s mule, 1779
The next significant improvement was
Samuel Crompton’s spinning mule;
it could make many types of threads
quickly and easily.

SEE ALSO Robots 74 · Jeans 226

73

1961
GEORGE DEVOL AND
JOSEPH ENGELBERGER

For centuries, people have
been fascinated with the idea
of building lifelike machines. Until
the 1900s, these were just clever toys,
but, in the 1950s, engineers began to
work on the idea seriously. Some of them
wanted to build a machine that would be
a step beyond the highly sophisticated
factory machines that were in use at the
time. They wanted to build an adaptable,
flexible machine that could do a range of
tasks, just like a human being can—they
wanted to build a robot.
Pioneers of robotics
Robots had been popular for many years
in science-fiction magazines and movies when
American engineers George Devol and Joseph
Engelberger were inspired to change science
fiction into science fact. In 1954, Devol patented
his idea of a “general purpose machine:” a
robot that could be programmed to transfer
items from place to place in a factory. In 1956,
he and Engelberger met, and they formed a
company called Unimation Inc. (Unimation
is short fo