x > b d y Li Na = e < s x I H Zr Be 3 y x = > K Ca Mg 2 W < ∞ y = Ni O Ti Fe c c HELP YOUR KIDS WITH n S iE e > x d = x S U Au Al > ∞ x Ar Pt He y x = y Pu C Ne C y x ∑ Kr Zn Ω Pb P 2 A UNIQUE STEP-BY-STEP VISUAL GUIDE HELcP YOUR KIDS WcITH n S iE e 1 1 1.0079 1 H HYDROGEN 2 3 6.941 4 2 Li 9.0122 B e LITHIUM BERYLLIUM 11 22.990 12 Na 24.305 M g SODIUM MAGNESIUM 9 3 39.098 20 4 K 40.078 21 5 Ca 44.956 22 6 OTASSIUM CALCIUM Sc Ti47.867 23 50.942 24 Rb85.468 38Sr87.62 39SYCAN8D8I.U90M6 40TITA9N1I.U2M24 41VANVADIU M CHRCOMrIU51M.996 sD3I2U.9M1 5B6STRO1N3T7I.U3M3 57Y7TT1RIUM ZIRZCONrIUM NNIOBIbU9M2.906 4M2 o95.94 4 a La-Lu 72 178.49 73 MOLYBDENUM TE M BARIU Hf 180.95 74 HELcP YOUR KIDS WcITH n S iE e A UNIQUE STEP-BY-STEP VISUAL GUIDE 7 8 6 25 9 54.938 26 10 Mn 55.845 27 11 Fe 58.933 28 12 MANGANESE IRON Co Ni58.693 29C 63.546 30 43 COBALT u Z Tc(96) 4R4 u101.07 45 102.91 46 NICKEL COPPER n ECHNETIUM RUTHE Rh Pd106.42 47 107.87 48 ZINC LLOONNDDOONN,, NNEEWW YYOORRKK,, MMEELLBBOOUURRNNEE,, MMUUNNIICCHH,, AANNDD DDEELLHHII DORLING KINDERSLEY Publishing Director Jonathan Metcalf Senior Editor Carron Brown Associate Publishing Director Liz Wheeler Project Editors Steven Carton, Art Director Phil Ormerod Matilda Gollon, Ashwin Khurana US Editors Jill Hamilton, Rebecca Warren DORLING KINDERSLEY INDIA Senior Designer Jim Green Illustrations: Project Art Editor Katie Knutton Managing Art Editor Arunesh Talapatra Art Editor Mary Sandberg Deputy Managing Art Editor Priyabrata Roy Designer Mik Gates Chowdhury Packagers Angela Ball, David Ball Senior Art Editor Chhaya Sajwan Art Editors Shruti Soharia Singh, Anjana Nair, Managing Editor Linda Esposito Priyanka Singh, Shipra Jain Managing Art Editor Diane Peyton Jones Assistant Art Editors Payal Rosalind Malik, Nidhi Mehra, Niyati Gosain, Neha Sharma, Category Publisher Laura Buller Jomin Johny, Vidit Vashisht Senior Production Controller Erika Pepe Editorial Assistance: Production Editor Adam Stoneham Deputy Managing Editor Pakshalika Jayaprakash Senior Editor Monica Saigal Jacket Editor Manisha Majithia Project Editor Roma Malik Jacket Designer Laura Brim First published in 2012 by Dorling Kindersley Limited, 80 Strand, London WC2R 0RL 12 13 14 10 9 8 7 6 5 4 3 2 1 001—181318—June/2012 Copyright © 2012 Dorling Kindersley Limited All rights reserved Without limiting the rights under copyright reserved above, no part of this publication may be reproduced, stored in or introduced into a retrieval system, or transmitted, in any form, or by any means (electronic, mechanical, photocopying, recording, or otherwise), without the prior written permission of both the copyright owner and the above publisher of this book. Published in Great Britain by Dorling Kindersley Limited A catalog record for this book is available from the Library of Congress. ISBN 978-0-7566-9268-1 DK books are available at special discounts when purchased in bulk for sales promotions, premiums, fund-raising, or educational use. For details, contact: DK Publishing Special Markets, 375 Hudson Street, New York, New York, 10014 or [email protected] Printed and bound by South China Printing Co. Ltd, China Discover more at www.dk.com TOM JACKSON has written nearly 100 books and contributed to many more about science, technology, and natural history. Before becoming a writer, Tom spent time as a zookeeper, worked in safari parks in Zimbabwe, and was a member of the first British research expedition to the rain forests of Vietnam since the 1960s. Tom’s work as a travel writer has taken him to the Sahara Desert, the Amazon jungle, the African savanna, and the Galápagos Islands—following in the footsteps of Charles Darwin. DR. MIKE GOLDSMITH has a Ph.D. in astrophysics from Keele University, awarded for research into variable supergiant stars and cosmic dust formation. From 1987 until 2007 he worked in the Acoustics Group at the UK’s National Physical Laboratory and was Head of the group for many years. His work there included research into automatic speech recognition, human speech patterns, environmental noise and novel microphones. He still works with NPL on a freelance basis and has recently completed a project to develop a new type of environmental noise mapping system. He has published more than forty scientific papers and technical reports, primarily on astrophysics and acoustics. Since 1999, Mike has written more than thirty science books for readers from babies to adults. Two of his books have been short-listed for the Aventis prize (now the Royal Society prize) for children’s science books. DR. STEWART SAVARD is the Science Head Teacher and district eLibrarian/eResource teacher in British Columbia’s Comox Valley, Canada. Stewart has published papers on the role of Science Fiction and Science collections in libraries and helped edit 18 Elementary Science books. He is actively developing a range of school robotics programs. ALLISON ELIA graduated from Brunel University in 1989, with a BSc (Hons) in Applied Physics. After graduating, she worked in Public Sector finance for several years, before realizing that her true vocation lay in education. In 1992 she undertook a PGCE in Secondary Science at Canterbury Christ Church College. For the past 18 years, Allison has taught Science in a number of schools across Essex and Kent and is currently the Head of Science at Fort Pitt Grammar School in Kent, UK. Introduction Science is vital to understanding everything in the Universe, from what makes the world go around to the workings of the human body. It explains why rainbows appear, how rockets work, and what happens when we flick a light switch. These may seem difficult subjects to get to grips with, but science needn’t be complex or baffling. In fact, much of science depends on simple laws and principles. Learn these, and how they can be applied, and even the most complicated concepts become more straightforward and understandable. This book sets out to explain the essentials of three key sciences—biology, chemistry, and physics. In particular, it focuses on the curricula for these subjects taught in schools worldwide for students between the ages of 9 and 16. This is often a crucial time for developing an understanding of science. Many children become confused by the terminology, equations, and sheer scale of some of the topics. Inevitably, parents—who themselves often have a limited understanding of science—are asked to help with homework. That is where this book can really come to the rescue. Help Your Kids with Science is designed to make all aspects of science easy and interesting. Beginning with a clear overview of what science is, each of the three sections is broken down into single-spread topics covering a key area of that science. The text is presented in short, easy-to-read chunks and is accompanied by clear, fully annotated diagrams and helpful equations. Explanations have been kept as simple as possible so that anyone—parent or child—can understand them. Another problem children often have with science is relating scientific concepts to real life. To help them make a connection, “Real World” panels have been introduced throughout the book. These give the reader a look at the practical applications of the science they’ve been reading about, and the exciting ways it can be used. Cross-references are used to link related topics and help reinforce the idea that many branches of science share the same basic principles. A useful reference section at the back provides quick and easy facts and explanations of terms used in the text. As a former research scientist, I am only too aware of how science can seem bewildering. Even scientists can get stuck if they stray into an unfamiliar discipline or are the first to investigate a new line of study. The trick is to get a firm grasp on the basics, and that is exactly what this book sets out to provide. From there you can go on to investigate how the world around you works and explore the endless possibilities that science has to offer mankind. DR. MIKE GOLDSMITH Contents INTRODUCTION by Dr. Mike Goldsmith 6 Evolution 80 WHAT IS SCIENCE? 10 Adaptations 82 THE SCIENTIFIC METHOD 12 Genetics I 84 FIELDS OF SCIENCE 14 Genetics II 86 Pollution 88 1 BIOLOGY Human impact 90 2 CHEMISTRY What is biology? 18 Variety of life 20 Cell structure 22 Cells at work 24 What is chemistry? 94 Fungi and single-celled life 26 Properties of materials 96 Respiration 28 States of matter 98 Photosynthesis 30 Changing states 100 Feeding 32 Gas laws 102 Waste materials 34 Mixtures 104 Transport systems 36 Separating mixtures 106 Movement 38 Elements and atoms 108 Sensitivity 40 Compounds and molecules 110 Reproduction I 42 Ionic bonding 112 Reproduction II 44 Covalent bonding 114 Life cycles 46 Periodic table 116 Hormones 48 Understanding the periodic table 118 Disease and immunity 50 Alkali metals and alkali earth metals 120 Animal relationships 52 The halogens and noble gases 122 Plants 54 Transition metals 124 Invertebrates 56 Radioactivity 126 Fish, amphibians, and reptiles 58 Chemical reactions 128 Mammals and birds 60 Combustion 130 Body systems 62 Redox reactions 132 Human senses 64 Energy and reactions 134 Human digestion 66 Rates of reaction 136 Brain and heart 68 Catalysts 138 Human health 70 Reversible reactions 140 Human reproduction 72 Water 142 Ecosystems 74 Acids and bases 144 Food chains 76 Acid reactions 146 Cycles in nature 78 Electrochemistry 148