For Professor Owen Gingerich, whose demonstration of Newton’s third law I will never forget—JPB

GROSSET & DUNLAP

Published by the Penguin Group

Penguin Group (USA) LLC, 375 Hudson Street, New York, New York 10014, USA

USA | Canada | UK | Ireland | Australia | New Zealand | India | South Africa | China

A Penguin Random House Company

Penguin supports copyright. Copyright fuels creativity, encourages diverse voices, promotes free speech, and creates a vibrant culture. Thank you for buying an authorized edition of this book and for complying with copyright laws by not reproducing, scanning, or distributing any part of it in any form without permission. You are supporting writers and allowing Penguin to continue to publish books for every reader.

Text copyright © 2014 by Janet B. Pascal. Illustrations copyright © 2014 by Tim Foley. Cover illustration copyright © 2014 by Nancy Harrison. All rights reserved. Published by Grosset & Dunlap, a division of Penguin Young Readers Group, 345 Hudson Street, New York, New York 10014. GROSSET & DUNLAP is a trademark of Penguin Group (USA) LLC.

Library of Congress Cataloging-in-Publication Data is available.

ISBN 978-0-698-18725-2