Genre
Nonfiction
Comprehension Skill
Compare and
Contrast
Text Features
• Captions
• Diagram
• Glossary
Science Content
Sound
Scott Foresman Science 3.14
ISBN 0-328-13849-5
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Vocabulary
Extended Vocabulary
compression wave
pitch
vibration
glider
Mach
sonic boom
sound barrier
space shuttle
SST
supersonic
Picture Credits
Every effort has been made to secure permission and provide appropriate credit for photographic material.
The publisher deeply regrets any omission and pledges to correct errors called to its attention in subsequent editions.
Photo locators denoted as follows: Top (T), Center (C), Bottom (B), Left (L), Right (R), Background (Bkgd).
Opener: US Department Of Defense/Photo Researchers, Inc.; 3 Getty Images; 4 Bettmann/Corbis;
6 Andy Crawford/Imperial War Museum, London /DK Images; 8 US Department Of Defense/Photo Researchers, Inc.;
11 (TC) Corbis; 12 George Hall/Corbis; 14 (CL) Richard Cohen/Corbis, (B) Charles M. Ommanney/Rex Features, Limited;
15 (TC) Dryden Flight/NASA.
Unless otherwise acknowledged, all photographs are the copyright © of Dorling Kindersley, a division of Pearson.
ISBN: 0-328-13849-5
Copyright © Pearson Education, Inc. All Rights Reserved. Printed in the United States of America.
This publication is protected by Copyright, and permission should be obtained from the publisher prior to any
prohibited reproduction, storage in a retrieval system, or transmission in any form by any means, electronic,
mechanical, photocopying, recording, or likewise. For information regarding permission(s), write to
Permissions Department, Scott Foresman, 1900 East Lake Avenue, Glenview, Illinois 60025.
3 4 5 6 7 8 9 10 V010 13 12 11 10 09 08 07 06 05
What did you learn?
1. What features did the Concorde
have that helped it fly fast?
2. How did people fly before the
airplane was invented?
3. What causes a sonic boom?
by Wendy Weiss
4.
You have read
about how the space shuttle is
actually a spaceship and not an
airplane. Write to explain what
makes the space shuttle
different from an airplane.
5.
Compare and Contrast Less than
fifty years separated the flights of
Orville and Wilbur Wright from
Captain Chuck Yeager’s flight that
broke the sound barrier. How were
their planes different? How were
they alike?
What You Already Know
Sound is everywhere! Whenever matter
moves or vibrates, it creates a sound. Many times
we can’t see these vibrations. But we can hear
their results!
Our ears catch vibrations traveling through
the air. When vibrations hit the eardrum, the
eardrum begins to vibrate. The vibrations then
pass to small bones in the eardrum before
traveling to the inner ear. Nerves in the inner
ear pass the vibration message to the brain.
Then it gets translated into a sound
we can identify.
Sounds can be loud
or soft. They can
also be high or low
in pitch.
When you strike a
gong, you can feel
the vibrations.
2
Sounds are made when matter begins to
vibrate. As matter vibrates, other matter
surrounding it squeezes and spreads apart.
The squeezing is called compression. Thus
sound moves away in wavelike patterns, called
compression waves, from matter as it vibrates.
Sound moves through different types of
matter at different rates of speed. Sound travels
fastest in solids. It moves the slowest through
air. Sound travels faster through steel than
through brick or plastic. The air temperature
also affects the speed at which sound travels.
Sound goes faster through warm air than it
does through cold air.
At sea level, sound
travels at about 340 meters
per second. It’s hard
to imagine, but today’s
planes can fly as fast as, or
faster than, the speed of
sound! Let’s learn how these
superfast planes work.
3
The First Airplane
The Wright brothers took to the air in the
first successful powered airplane flight in 1903.
Before that, people had dreamed about flying
for thousands of years. In the late 1700s, the
Montgolfier brothers of France invented the hot
air balloon. Although it did let people fly, it was
hard to control. The balloon really just drifted
on the wind. For flight to be useful, people had
to be able to control where they were going.
The Wright brothers built the first
flying machine with an engine
to push it forward and
controls to steer it.
First, the Wright brothers studied the
shape of birds’ wings in order to build a glider.
A glider is a flying machine without an engine.
The Wright brothers jumped off hills and
sand dunes in North Carolina with their glider.
Their next step was to put an engine on a flying
machine, making it a powered airplane.
On December 17, 1903, the brothers flew!
Orville and Wilbur each made two flights that
day. On each attempt, the plane flew for at least
one hundred feet. The Wright brothers had
shown that people could use power to fly under
their own control!
The Wright Flyer flew successfully on
December 17, 1903, in Kitty Hawk,
North Carolina.
The Montgolfier hot air
balloon first flew over
Paris in 1783.
4
5
The Sound Barrier
Improvements in airplane designs followed
soon after the Wright brothers’ historic first
flight. People built new planes that could fly
longer distances and land more smoothly.
Planes were developed that could go faster.
Soon, people were building planes that could
even carry passengers! All the time, pilots were
being asked to test new types of planes. There
was a constant effort to make airplanes that
could fly faster and faster.
The P-51 Mustang fighter
plane was used during
World War II.
6
Chuck Yeager flew faster
than the speed of sound in
a plane much like this one.
By the end of World War II in 1945, early
jet airplanes could reach speeds of five hundred
miles per hour. When planes approached that
speed, however, pilots would lose control and
often crash. Pilots and engineers knew that the
problem involved planes flying near the speed of
sound. Some of them thought that there might
be a sound barrier in the air. Those who believed
in the sound barrier considered it impossible for
planes ever to fly at or above the speed of sound.
In 1947, Captain Chuck Yeager shattered
this myth when he flew faster than the speed of
sound! He discovered that once a plane passed
the speed of sound, or Mach 1, the flight became
very smooth.
7
Approaching Mach 1
Sonic Boom
Whenever an object goes into motion, it causes
the sound waves in front of it to push together.
As a plane approaches the speed of sound, these
waves are forced together very quickly. They
pile up on each other, building up tremendous
amounts of pressure. When the pressure gets
to be too great, it must be released. That release
happens in the form of a shock wave. A shock
wave makes a sound known as a sonic boom.
Many things affect a sonic boom, such as the
size, weight, and shape of the object. The sonic
boom is also affected by the altitude, flight path,
and weather conditions.
Sometimes it is possible
to see a jet fighter break
through the sound barrier.
8
Sound waves
behave normally
while the plane flies
at slower speeds.
Tremendous pressure
forces the waves
together as the plane
approaches Mach 1.
The sonic boom
occurs when the
plane hits Mach 1.
The speed sound travels at is called Mach 1.
Supersonic planes are planes that are capable
of flying faster than Mach 1. The higher in the
atmosphere a supersonic airplane travels, the
weaker its sonic boom will be. Shape is important
too. Long, thin airplanes disturb the air less, making
weaker sonic booms.
9
Supersonic Airliner
In 1956, a committee formed in England to
try to build a supersonic airplane that could
carry passengers. The idea of a supersonic
passenger airplane became popular. So in the
1960s, France and England worked together to
build the first supersonic transport, or SST.
It was named the Concorde. The first supersonic
test flight of the Concorde took place on
October 1, 1969. Airlines started using the
Concorde in 1976.
The Concorde’s long, thin shape
made it easier for the plane to fly
at supersonic speeds.
10
Two pilots fit tightly into the Concorde’s cockpit.
The Concorde flew at about Mach 2. It cut
the flight time from London to New York in half,
from about six hours to about three hours. In
order for the Concorde to travel at supersonic
speeds, it was built out of very light materials.
The Concorde had a long and narrow body that
could only fit about one hundred passengers. Its
wings were swept back so the plane could cut
through the air easily. Airlines stopped using the
Concorde in 2003.
The Concorde’s pointy
nose and narrow
width helped it reach
supersonic speeds.
11
Faster and Faster
Did you know that there are planes that can
fly at speeds of Mach 3? The SR-71 Blackbird is
truly built for speed!
The Blackbird was first built in the 1960s. It
could travel at 2,200 miles per hour, or Mach 3,
at eighty thousand feet above Earth. Blackbird
pilots had to wear pressure suits to fly safely at
that great height. In addition, the front edge of
the Blackbird heated up to 600˚F while it was in
flight! All the Blackbirds have now been retired.
The SR-71 Blackbird was one of
the fastest planes ever built.
12
The space shuttle reenters Earth’s
atmosphere by gliding.
The space shuttle flies faster than either the
Concorde or the Blackbird. It travels way above
the atmosphere, in outer space. Because of that,
the space shuttle is considered a spaceship, not
an airplane. In space, there is no matter for the
shuttle to push out of the way. In fact, the space
shuttle does not make any sonic booms once it
has reached its orbiting altitude. Space has very
different properties than Earth’s atmosphere.
Because of that, the space shuttle behaves very
differently from an airplane while it travels in space.
13
A Supersonic Future
Even though the Concorde is no longer
being used, supersonic travel may well
continue to be a part of human air travel.
Experts are now looking at the Concorde’s
design to see if it can be remodeled and
used again. Also, designs for entirely new
supersonic passenger planes are being put
together. As long as there are people willing to
pay to travel at supersonic speeds, it is likely
that new passenger airplanes with supersonic
capabilities will be developed.
The Concorde stopped
making passenger flights
in 2003.
14
NASA is currently developing the experimental
Hyper-X plane, also known as the X-43.
Planes aren’t the only vehicles capable of
traveling faster than the speed of sound. In 1997,
a supersonic car broke the land speed record by
traveling at about 760 miles per hour. Scientists
are even working to make a supersonic train!
Only sixty years ago, there were scientists who
believed that nothing could travel at the speed of
sound. Today, many kinds of vehicles can travel
at Mach 1. We live in an age of speed!
Land-based rocket cars can
now travel at Mach 1!
15
Vocabulary
Glossary
compression wave
pitch
glider
vibration
Mach
Extended Vocabulary
glider
Mach
an aircraft
designed to fly
withoutsonic
using boom
an engine
sound barrier
a unit ofspace
measure
for describing
shuttle
an object’s
SSTspeed relative to the
speed ofsupersonic
sound. Mach 1 is equal
to the speed of sound.
sonic boom
the sound aircraft make as they
speed past Mach 1
sound barrier
an imaginary obstacle that some
people thought would prevent
aircraft from flying at or above
the speed of sound
space shuttle
a spacecraft that travels at Mach
speeds above the atmosphere
in space
Photo locators denoted as follows: Top (T), Center (C), Bottom (B), Left (L), Right (R), Background (Bkgd).
Picture Credits
Every effort has been made to secure permission and provide appropriate credit for photographic material.
The publisher deeply regrets any omission and pledges to correct errors called to its attention in subsequent editions.
Opener: US Department Of Defense/Photo Researchers, Inc.; 3 Getty Images; 4 Bettmann/Corbis;
6 Andy Crawford/Imperial War Museum, London /DK Images; 8 US Department Of Defense/Photo Researchers, Inc.;
11 (TC) Corbis; 12 George Hall/Corbis; 14 (CL) Richard Cohen/Corbis, (B) Charles M. Ommanney/Rex Features, Limited;
15 (TC) Dryden Flight/NASA.
SST
supersonic transport; The
Concorde was the first SST.
Unless otherwise acknowledged, all photographs are the copyright © of Dorling Kindersley, a division of Pearson.
supersonic
traveling faster than the speed
of sound
ISBN: 0-328-13849-5
Copyright © Pearson Education, Inc. All Rights Reserved. Printed in the United States of America.
This publication is protected by Copyright, and permission should be obtained from the publisher prior to any
prohibited reproduction, storage in a retrieval system, or transmission in any form by any means, electronic,
mechanical, photocopying, recording, or likewise. For information regarding permission(s), write to
Permissions Department, Scott Foresman, 1900 East Lake Avenue, Glenview, Illinois 60025.
3 4 5 6 7 8 9 10 V010 13 12 11 10 09 08 07 06 05
16
What did you learn?
1. What features did the Concorde
have that helped it fly fast?
2. How did people fly before the
airplane was invented?
3. What causes a sonic boom?
4.
You have read
about how the space shuttle is
actually a spaceship and not an
airplane. Write to explain what
makes the space shuttle
different from an airplane.
5.
Compare and Contrast Less than
fifty years separated the flights of
Orville and Wilbur Wright from
Captain Chuck Yeager’s flight that
broke the sound barrier. How were
their planes different? How were
they alike?