Glass Blowing. ì<(sk$m)=bdeaja< +^-Ä-U-Ä-U. by J. Matteson Claus. Scott Foresman Reading Street 3.6.5

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1 Suggested levels for Guided Reading, DRA, Lexile, and Reading Recovery are provided in the Pearson Scott Foresman Leveling Guide. Glass Blowing Genre Expository nonfiction Comprehension Skills and Strategy Generalize Compare and Contrast Predict Text Features Captions Heads Glossary Scott Foresman Reading Street ì<(sk$m)=bdeaja< +^-Ä-U-Ä-U ISBN by J. Matteson Claus

2 Vocabulary burros bursts factory glassblower puff reply tune Glass Blowing Word count: 663 by J. Matteson Claus Note: The total word count includes words in the running text and headings only. Numerals and words in chapter titles, captions, labels, diagrams, charts, graphs, sidebars, and extra features are not included. Editorial Offices: Glenview, Illinois Parsippany, New Jersey New York, New York Sales Offices: Needham, Massachusetts Duluth, Georgia Glenview, Illinois Coppell, Texas Ontario, California Mesa, Arizona

3 Introduction Look around you. Are there windows? Is there a glass of water? Are there lights? You might reply, Yes! All of these things are made of glass. Today glass is very common. But at one time, glass was as precious as gold. 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. Unless otherwise acknowledged, all photographs are the property of Scott Foresman, a division of Pearson Education. Photo locators denoted as follows: Top (T), Center (C), Bottom (B), Left (L), Right (R), Background (Bkgd) Opener Fulvio Roiter/Corbis; 1 James L. Amos/Corbis; 3 Warren Morgan/Corbis; 4 Jonathan Blair/Corbis; 5 Elio Ciol/Corbis; 6 James L. Amos/Corbis; 7 Peter Harholdt/Corbis; 8 Tim Thompson/Corbis; 9 Dean Conger/Corbis; 10 James L. Amos/Corbis; 11 James L. Amos/Corbis; 12 Bojan Brecelj/Corbis; 13 Fulvio Roiter/ Corbis; 14 Marvin Koner/Corbis ISBN: Copyright Pearson Education, Inc. All Rights Reserved. Printed in China. 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 V0H

4 The History of Glass People began making glass thousands of years ago. Glass objects have been found that are more than 5,000 years old. They have been found in ancient Egyptian tombs. Legend says that the first glass was made by accident. But no one really knows for sure. According to the story, some sailors built a fire on the beach. They set their cooking pot on blocks over the fire. The fire got too hot, and it melted the blocks and the sand. Together, these formed glass. Ancient glass artifact These ancient Egyptian weights from a balance scale were made of green glass. 4 5

5 For a long time, glass could only be made slowly. The Egyptians had a way. They melted glass until it was very hot almost a liquid. Then they shaped the hot glass around a mold. This process was very slow and expensive. As a result, glass was rare. It was as precious as gold and jewels. Only wealthy people could afford it. The Art of Glass Blowing The Art of Glass Blowing Then people discovered the art of blowing glass. This changed everything. Now glass could be made quickly. By using this new way, a glassblower could make many glass items in one day. Glass became available to everyone. Scientists have found glass blowing equipment dating back thousands of years. 6 7

6 Glass has three main ingredients: sand, soda, and lime. Different combinations of these ingredients make different kinds of glass. Before starting, the glassblower puts on safety goggles and gloves. The first step is to melt the ingredients. This needs a very hot furnace about 2,500ºF. Also, broken glass, called cullet, can be melted. Glass is recyclable! Next, the glassblower dips a long rod, called a blowpipe, into the melted glass. The blowpipe picks up a glob of the melted glass. The glassblower then pulls the glob out of the furnace. 8 Step 1: Melting the Glass Step 2: Gathering a Glob of Molten Glass 9

7 Next, the glassblower blows into the blowpipe to create a glass bubble. If the glassblower blows too gently, the bubble won t get big enough. If the glassblower puffs too hard, the bubble bursts. Glass blowing needs just the right amount of breath to make the melted glass into a bubble. Once the bubble is blown, the glassblower and some helpers can shape the glass. They twist and turn the rod to help the glass keep its shape. They use tools to shape the glass into objects such as cups and vases. Then they cut the object off from the rod. Step 4: Shaping the Glass 10 Step 3: Blowing a Glass Bubble 11

8 The glass must be cooled slowly, or it will break easily. The cooling process takes place in a special oven. This final step may take several hours. Then the project is done! The Finished Product The Finished Product Not all glass is the same color. The natural color of glass is green or greenishblue. That color comes from iron oxide in the sand. To create other colors in glass, chemicals are added. For example, adding cobalt makes glass blue. Chemicals are added to make glass into different colors. 12 Step 5: Cooling the Glass 13

9 Glass blowing hasn t changed much over the years. The tools have changed, however. Today glassblowers have many tools to help with the work. Where once burros carted ingredients, today trucks deliver large loads. Glass blowing has become an art. Some glass objects, however, are made in a factory, where machines have taken over. For example, pop bottles are made in a factory. Machines run by computers do the work. The machines take the glass from the furnace, blow just the right amount of air into it, and mold the glass into bottles. Factories and machines are able to make thousands of bottles quickly. Glass is used for everything from test tubes to glass eyes. It is used for everyday objects, such as drinking glasses and TV screens. It is used for art, such as colorful windows and glass chimes that play a tune in the wind. As it has in the past, glass blowing continues to provide useful and beautiful objects to people everywhere. Today, factories can produce thousands of glass bottles in the time it took to make one

10 Glossary burros n. small donkeys, often used as pack animals bursts v. explodes factory n. a place where goods are manufactured glassblower n. a person who shapes molten glass by blowing air into a tube puffs v. gives a short, forceful breath reply v. to give an answer tune n. a piece of music; a melody Reader Response 1. Based on what you have read, tell one important thing you learned about glass. 2. What do you predict are some new ways that glass might be used in the future? 3. Use the following vocabulary words in sentences: glassblower, puff, burst. 4. What are the five steps in glass blowing? Use a chart like the one below to list the steps in order. 16