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Under the Microscope In the Home Sabrina Crewe Consultant: Professor Anne K. Camper, Montana State University Copyright © 2010 by Infobase Publishing All rights reserved. No part of this book may be reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying, recording, or by any information storage or retrieval systems, without permission in writing from the publisher. For information contact: Chelsea Clubhouse An imprint of Chelsea House 132 West 31st Street New York NY 10001 Library of Congress Cataloging-in-Publication Data Crewe, Sabrina. Under the microscope : in the home / Sabrina Crewe. p. cm. Includes index. ISBN 978-1-60413-823-8 (hardcover) ISBN 978-1-4381-3248-8 (e-book) 1. Microorganisms--Juvenile literature. 2. Microscopy--Juvenile literature. 3. Housing and health-Juvenile literature. I. Title. QR57.C743 2010 579.028’2--dc22 2009041203 Chelsea Clubhouse books are available at special discounts when purchased in bulk quantities for businesses, associations, institutions, or sales promotions. Please call our Special Sales Department in New York at (212) 967-8800 or (800) 322-8755. You can find Chelsea Clubhouse on the World Wide Web at http://www.chelseahouse.com Text design by Sabine Beaupré Illustrations by Stefan Chabluk Originated by Discovery Books Composition by Discovery Books Cover printed by Bang Printing, Brainerd, MN Book printed and bound by Bang Printing, Brainerd, MN Date printed: May 2010 Printed in the United States of America 10 9 8 7 6 5 4 3 2 1 This book is printed on acid-free paper. All links and Web addresses were checked and verified to be correct at the time of publication. Because of the dynamic nature of the Web, some addresses and links may have changed since publication and may no longer be valid. Acknowledgments We would like to thank the following for permission to reproduce photographs: Centers for Disease Control and Prevention, US Department of Health and Human Services: pp. 11, 12; Dennis Kunkel Microscopy, Inc.: pp. 9, 10, 13 bottom, 14, 16, 18, 22, 23, 27 top; MicroAngela: pp. 20, 21 right; Rocky Mountain Laboratories, The National Institute of Allergy and Infectious Diseases: p. 15; Science Photo Library: pp. 5 (Andrew Syred), 7 (Andrew Syred), 17 (Jeremy Burgess), 19 (Andrew Syred), 25 (Susumu Nishinaga), 26 top (Volker Steger), 27 middle (Andrew Syred), 27 bottom (Eye of Science); Shutterstock Images: pp. 4 (Rob Marmion), 8 (Photoroller), 21 left (Alice Mary Herden Vision-Vault LLC), 24 (Rudyanto Wijaya), 26 bottom (Jasenka Lukša), 29 top (3445128471), 29 bottom (Nikola Spasenoski). Contents A Hidden World in Your Home 4 Dust Mites 6 Looking Closer at Dust 8 Bugs in the Bed 10 In the Bathroom 12 In the Kitchen 14 Fungi at Home 16 Close-up on Clothes 18 Pet Parasites 20 Household Mini-Monsters 22 Bigger Bugs 24 Everyday Stuff 26 Size and Scale 28 About Microscopes 28 Micro-Detective 29 Glossary 30 Explore These Web Sites 31 Index 32 Some words are bold the first time they appear in the text. These words are explained in the glossary at the back of this book. A Hidden World in Your Home Who lives in your home? You, of course, and other members of your family, and maybe you have a pet. But did you know that your home is also home to an invisible population of microscopic living things? b Billions of microorganisms There are billions of microorganisms in your home. Microorganisms are living things that are too small to be seen without a microscope. They come in many sizes, starting with tiny and getting even tinier. Microorganisms live in your bed, in your kitchen, and even on your pets. The biggest microorganisms are very small insects and other animals. The smaller ones—which are not animals— are often known as microbes. Some microbes are like miniature animals, while others are more like plants. Even smaller are the bacteria that are everywhere around us. T E t s L We all share our homes with billions of microorganisms! 4 I a a l h s o m a In real life, this tip of a pin is only 0.03 millimeters across. It has been magnified 1,500 times. If you looked at it without a microscope, you would never know that it was covered in bacteria. bacteria There are more bacteria on Earth than any other living things, and yet we can’t see them. Looking closer How Small Is Small? A dust mite is 0.2 to 0.5 millimeters long—so small that it can live in your carpet unnoticed. But it is still several thousand times bigger than the smallest microbes. We’ll find out more about dust mites next. In this book, we’ll use a microscope to take a look at the hidden life-forms in your home. We’ll also see some familiar household objects under the microscope. You will discover a whole new world in your home! 5 Dust Mites The first microscopic creature we’re going to look at is the dust mite. There are millions of them in every part of your home where dust collects. Pieces of you You may be surprised to learn that most of this dust comes from living things—especially you. Much of the dust in our homes consists of human skin! Every hour, a person will shed about 1.5 million flakes of dead skin. The flakes are tiny, but that’s still a whole lot of skin. Delicious skin Skin is the favorite food of the dust mite. These microscopic animals eat by squirting juice from their digestive systems onto flakes of skin. The juices turn the skin into liquid, and the dust mites suck it up. Not surprisingly, the dust mite’s favorite places are those where they will find the most skin flakes, such as under your bed or in your pillows and mattress. Dust mites live all over the house, however: in carpets, couches, and armchairs. These places trap a lot of dust, so you can find many mites there, too. In fact, you will be sure to find them in any nook Micro-Fact and cranny that traps dust. In just one ounce of household A bed may hold dust, there can be 30,000 to about 2 million 40,000 dust mites like the dust mites. one opposite! 6 Arachnids Dust mites are arachnids, which means they are in the same family of animals as spiders and scorpions. Arachnids have eight legs, no antennae, and no wings.  Looking Closer at Dust Dust is everywhere in our homes. Even if you clean your room every week, you will soon find specks of dust on your dresser and gray fluff under the bed. We already know that skin is a big part of dust, but what else do we find when we look at dust through a microscope? Dust Allergies You may know people who have allergies to dust—maybe you have an allergy yourself. Pollen in dust can cause allergies, but there isn’t that much pollen inside your home. Usually, dust allergies are caused by feces (droppings) from microanimals that live in our homes. Top of the list for allergycausing droppings are dust mites. Other stuff in dust Most of us live in cities, and dirt is in the air all around us. A lot of this dirt comes from vehicle engines and power plants. Some of it comes into your home through windows and doors and settles on surfaces. Grains of pollen, sand, and soil also float into your house from outside.  The things bugs leave behind make a lot of dust, too: spiders’ webs, droppings from insects, and microscopic pieces of dead bugs. You’ll also find a lot of fibers from clothes, towels, and carpet. Other strands in dust include hairs from people and pets. In In this close-up areas where people eat, view of house dust, the dust contains crumbs parts have been colored so you can see them more clearly. of food, too. The yellow shape is a grain of pollen. Other microscopic plant parts are green. The dark brown strand is a dog hair, and the orange strand is a cat hair. The purple, pink, and blue fragments are all fibers from cloth. Most of the brown stuff is dead skin from people and animals. 9