The Solar System

The Solar System Ray White Stamp Copyright © by Harcourt, Inc. All rights reserved. No part of this publication may be reproduced or transmitted in any form or by any means, electronic or mechanical, including photocopy, recording, or any information storage and retrieval system, without permission in writing from the publisher. Requests for permission to make copies of any part of the work should be addressed to School Permissions and Copyrights, Harcourt, Inc., 6277 Sea Harbor Drive, Orlando, FL 32887-6777. Fax: 407-345-2418. HARCOURT and the Harcourt Logo are registered trademarks of Harcourt, Inc., registered in the United States of America and/or other jurisdictions. Printed in the United States of America ISBN 0-15-343829-0 1 2 3 4 5 6 7 8 9 10 179 10 09 08 07 06 05 04 Visit The Learning Site! www.harcourtschool.com Orlando Austin New York San Diego Toronto London The Solar System The Solar System . . . . . . . . .2 Stars . . . . . . . . . . . . . . . . . . .4 Day and Night. . . . . . . . . . .6 The Moon. . . . . . . . . . . . . . .8 Seasons . . . . . . . . . . . . . . .10 Ray sm Blue Stamp Ray sm Blue Stamp Ray sm Blue Stamp Ray sm Blue Stamp Ray sm Blue Stamp Ray sm Blue Stamp Mercury Venus Mars Earth sun The sun is the center of the solar system. Nine planets move around the sun. Earth is one of the planets. The Solar System 2 Ray sm Blue Stamp Ray sm Blue Stamp Ray sm Blue Stamp Ray sm Blue Stamp Ray sm Blue Stamp Ray sm Blue Stamp Ray sm Blue Stamp Ray sm Blue Stamp Ray sm Blue Stamp Jupiter Uranus Saturn Neptune Pluto 3 Planets are made of rock or gas. Some planets have moons. Some do not. Some are close to the sun. Some are not. Each planet moves in its own orbit. Ray sm Blue Stamp Ray sm Blue Stamp Ray sm Blue Stamp Ray sm Blue Stamp Ray sm Blue Stamp Ray sm Blue Stamp Ray sm Blue Stamp Ray sm Blue Stamp Ray sm Blue Stamp 4 Stars The sun is a star. It is made of hot gases. The hot gases give off light and heat. The sun is the closest star to Earth. We see other stars only at night. stars Ray sm Blue Stamp Ray sm Blue Stamp Ray sm Blue Stamp Ray sm Blue Stamp Ray sm Blue Stamp Ray sm Blue Stamp 5 A group of stars may form a constellation. A constellation is a pattern of stars. A Orion D Little Dipper, part of the constellation Ursa Minor A Big Dipper, part of the constellation Ursa Major Ray sm white stamp Ray sm white stamp Ray sm white stamp Ray sm Blue Stamp Ray sm Blue Stamp 6 Day and Night The sun seems to move across the sky. But the sun does not move. Earth moves. Earth rotates, or spins like a top. It takes about 24 hours to make one turn. day Ray sm Blue Stamp Ray sm Blue Stamp Ray sm Blue Stamp Ray sm Blue Stamp Ray sm Blue Stamp Ray sm Blue Stamp 7 At times, our part of Earth faces the sun. That is when we have day. Then, our part faces away from the sun. That is when we have night. night Ray sm Blue Stamp Ray sm Blue Stamp Ray sm Blue Stamp Ray sm Blue Stamp Ray sm Blue Stamp 8 The Moon The moon is a ball of rock. It moves in an orbit around Earth. One full orbit takes about a month. B moon Earth Ray sm white stamp Ray sm white stamp Ray sm Blue Stamp Ray sm Blue Stamp Ray sm Blue Stamp Ray sm Blue Stamp 9 The moon reflects light from the sun. The part of the moon we see changes. That is why its shape seems to change. crescent moon first quarter moon last quarter moon full moon Ray sm Blue Stamp Ray sm Blue Stamp Ray sm Blue Stamp Ray sm Blue Stamp Ray sm Blue Stamp Ray sm Blue Stamp Ray sm Blue Stamp 10 Seasons The Earth moves in an orbit around the sun. One full orbit takes about 365 days, a year. As the Earth orbits, its tilt stays the same. That is why we have seasons. spring summer Ray sm Blue Stamp Ray sm Blue Stamp Ray sm Blue Stamp Ray sm Blue Stamp Ray sm Blue Stamp Ray sm Blue Stamp Ray sm Blue Stamp 11 At times, our part of Earth tilts toward the sun. That is when we have summer. Then, our part tilts away from the sun. That is when we have winter. winter fall orbit Ray sm Blue Stamp Ray sm Blue Stamp Ray sm Blue Stamp Ray sm Blue Stamp Ray sm Blue Stamp Ray sm Blue Stamp Ray sm Blue Stamp Vocabulary constellation, p. 5 moon, p. 8 orbit, p. 3 planet, pp. 2–3 rotate, p. 6 season, p. 10 solar system, p. 2 star, p. 4 12 Ray sm Blue Stamp Ray sm Blue Stamp Ray sm Blue Stamp Ray sm Blue Stamp Ray sm Blue Stamp Ray sm Blue Stamp Ray sm Blue Stamp Ray sm Blue Stamp Ray sm Blue Stamp School-Home Connection Tell a family member what you have read about the solar system. Talk with the family member about objects you have seen in the sky. Hands-On Activity 1. You can see how a shadow changes as Earth rotates. Shine a flashlight on a wall. This is light from the sun. Use your fingers to make a shadow. 2. Move your hand, but do not move the flashlight. What happens to the shadow? Think About the Reading 1. What questions do you have after reading this book? 2. How can you find answers to these questions? Ray sm Blue Stamp Ray sm Blue Stamp Ray sm Blue Stamp Ray sm Blue Stamp Ray sm Blue Stamp