GenreGenre Comprehension SkillComprehension Skill Text FeaturesText Features Science ContentScience Content Nonfi ctionNonfi ction Compare andCompare and • Captions• Captions SoundSound ContrastContrast • Diagram• Diagram • Glossary• Glossary Scott Foresman Science 3.14Scott Foresman Science 3.14 ì<(sk$m)=bdieje<ì<(sk$m)=bdieje<ISBNISBN 0-328-13849-50-328-13849-5 +^-Ä-U-Ä-U+^-Ä-U-Ä-U
Vocabulary Extended Vocabulary What did you learn? compression wave glider pitch Mach 1. What features did the Concorde vibration sonic boom have that helped it fl y fast? sound barrier space shuttle 2. How did people fly before the SST airplane was invented? supersonic 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. Picture Credits 5. Compare and Contrast Less than 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. fifty years separated the fl ights of Photo locators denoted as follows: Top (T), Center (C), Bottom (B), Left (L), Right (R), Background (Bkgd). Orville and Wilbur Wright from 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.; Captain Chuck Yeager’s flight that 11 (TC) Corbis; 12 George Hall/Corbis; 14 (CL) Richard Cohen/Corbis, (B) Charles M. Ommanney/Rex Features, Limited; 15 (TC) Dryden Flight/NASA. broke the sound barrier. How were Unless otherwise acknowledged, all photographs are the copyright © of Dorling Kindersley, a division of Pearson. their planes different? How were they alike? 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 You Already Know Sound is everywhere! Whenever matter Sounds are made when matter begins to moves or vibrates, it creates a sound. Many times vibrate. As matter vibrates, other matter we can’t see these vibrations. But we can hear surrounding it squeezes and spreads apart. their results! The squeezing is called compression. Thus Our ears catch vibrations traveling through sound moves away in wavelike patterns, called the air. When vibrations hit the eardrum, the compression waves, from matter as it vibrates. eardrum begins to vibrate. The vibrations then Sound moves through different types of pass to small bones in the eardrum before matter at different rates of speed. Sound travels traveling to the inner ear. Nerves in the inner fastest in solids. It moves the slowest through ear pass the vibration message to the brain. air. Sound travels faster through steel than Then it gets translated into a sound through brick or plastic. The air temperature we can identify. also affects the speed at which sound travels. Sounds can be loud Sound goes faster through warm air than it or soft. They can does through cold air. also be high or low in pitch. At sea level, sound travels at about 340 meters When you strike a per second. It’s hard gong, you can feel to imagine, but today’s the vibrations. planes can fly as fast as, or faster than, the speed of sound! Let’s learn how these superfast planes work. 2 3
The First Airplane First, the Wright brothers studied the shape of birds’ wings in order to build a glider. The Wright brothers took to the air in the A glider is a flying machine without an engine. first successful powered airplane flight in 1903. The Wright brothers jumped off hills and Before that, people had dreamed about flying sand dunes in North Carolina with their glider. for thousands of years. In the late 1700s, the Their next step was to put an engine on a flying Montgolfier brothers of France invented the hot machine, making it a powered airplane. air balloon. Although it did let people fly, it was On December 17, 1903, the brothers flew! hard to control. The balloon really just drifted Orville and Wilbur each made two flights that on the wind. For flight to be useful, people had day. On each attempt, the plane flew for at least to be able to control where they were going. one hundred feet. The Wright brothers had The Wright brothers built the first shown that people could use power to fly under flying machine with an engine their own control! to push it forward and The Wright Flyer flew successfully on controls to steer it. December 17, 1903, in Kitty Hawk, North Carolina. The Montgolfi er hot air balloon fi rst fl ew 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 Chuck Yeager flew faster longer distances and land more smoothly. than the speed of sound in Planes were developed that could go faster. a plane much like this one. Soon, people were building planes that could even carry passengers! All the time, pilots were By the end of World War II in 1945, early being asked to test new types of planes. There jet airplanes could reach speeds of five hundred was a constant effort to make airplanes that miles per hour. When planes approached that could fly faster and faster. speed, however, pilots would lose control and often crash. Pilots and engineers knew that the problem involved planes flying near the speed of The P-51 Mustang fi ghter plane was used during sound. Some of them thought that there might World War II. 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. 6 7
Sonic Boom Approaching Mach 1 Whenever an object goes into motion, it causes Sound waves the sound waves in front of it to push together. behave normally As a plane approaches the speed of sound, these while the plane fl ies at slower speeds. waves are forced together very quickly. They pile up on each other, building up tremendous amounts of pressure. When the pressure gets Tremendous pressure to be too great, it must be released. That release forces the waves happens in the form of a shock wave. A shock together as the plane approaches Mach 1. 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 The sonic boom boom is also affected by the altitude, flight path, occurs when the and weather conditions. plane hits Mach 1. Sometimes it is possible to see a jet fi ghter break The speed sound travels at is called Mach 1. through the sound barrier. 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. 8 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. Two pilots fi t tightly into the Concorde’s cockpit. It was named the Concorde. The first supersonic The Concorde flew at about Mach 2. It cut test flight of the Concorde took place on the flight time from London to New York in half, October 1, 1969. Airlines started using the from about six hours to about three hours. In Concorde in 1976. 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 The Concorde’s long, thin shape supersonic speeds. made it easier for the plane to fly at supersonic speeds. 10 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 space shuttle reenters Earth’s atmosphere by gliding. The SR-71 Blackbird was one of The space shuttle flies faster than either the the fastest planes ever built. 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. 12 13
A Supersonic Future Even though the Concorde is no longer being used, supersonic travel may well NASA is currently developing the experimental continue to be a part of human air travel. Hyper-X plane, also known as the X-43. Experts are now looking at the Concorde’s design to see if it can be remodeled and Planes aren’t the only vehicles capable of used again. Also, designs for entirely new traveling faster than the speed of sound. In 1997, supersonic passenger planes are being put a supersonic car broke the land speed record by together. As long as there are people willing to traveling at about 760 miles per hour. Scientists pay to travel at supersonic speeds, it is likely are even working to make a supersonic train! that new passenger airplanes with supersonic Only sixty years ago, there were scientists who capabilities will be developed. 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! The Concorde stopped making passenger fl ights in 2003. Land-based rocket cars can now travel at Mach 1! 14 15
Vocabulary Extended Vocabulary What did you learn? Glossary compression wave glider pitch Mach 1. What features did the Concorde glider an aircraft designed to fly vibration sonic boom have that helped it fl y fast? without using an engine sound barrier Mach a unit of measure for describingspace shuttle 2. How did people fly before the an object’s speed relative to theSST airplane was invented? speed of sound. Mach 1 is equalsupersonic to the speed of sound. 3. What causes a sonic boom? sonic boom the sound aircraft make as they speed past Mach 1 4. You have read about how the space shuttle is sound barrier an imaginary obstacle that some actually a spaceship and not an people thought would prevent airplane. Write to explain what aircraft from flying at or above makes the space shuttle the speed of sound different from an airplane. space shuttle a spacecraft that travels at Mach Picture Credits speeds above the atmosphere 5. Compare and Contrast Less than 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.in space fifty years separated the fl ights of Photo locators denoted as follows: Top (T), Center (C), Bottom (B), Left (L), Right (R), Background (Bkgd). Orville and Wilbur Wright from 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.;SST supersonic transport; The Captain Chuck Yeager’s flight that 11 (TC) Corbis; 12 George Hall/Corbis; 14 (CL) Richard Cohen/Corbis, (B) Charles M. Ommanney/Rex Features, Limited;Concorde was the first SST. 15 (TC) Dryden Flight/NASA. broke the sound barrier. How were Unless otherwise acknowledged, all photographs are the copyright © of Dorling Kindersley, a division of Pearson. supersonic traveling faster than the speed their planes different? How were of sound they alike? 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 0516
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