Patterns in the Sky Lessons 1–2 CXECA08ARD304_LLR_CVa.indd 2/22/06 2:28:49 PM NOTE: In 2006, scientists from the International Astronomical Union classified Pluto as a “dwarf planet.” However, not all scientists agree with the decision Use the Internet or current newspaper and magazine articles to find the latest information about the planets 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, Florida 32887-6777 Fax: 407-345-2418 HARCOURT and the Harcourt Logo are trademarks of Harcourt, Inc., registered in the United States of America and/or other jurisdictions Printed in the United States of America ISBN-13: 978-0-15-349167-2 ISBN-10: 0-15-349167-1 10 179 15 14 13 12 11 10 09 08 07 06 If you have received these materials as examination copies free of charge, Harcourt School Publishers retains title to the materials and they may not be resold Resale of examination copies is strictly prohibited and is illegal Possession of this publication in print format does not entitle users to convert this publication, or any portion of it, into electronic format CXECA08ARD304_LLR_CVa.indd 10/6/06 10:02:28 AM Patterns in the Sky Lessons 1–2 Lesson What Planets Orbit the Sun? Lesson What Patterns Do Earth and the Sun Follow? 12 Visit The Learning Site! www.harcourtschool.com CXECA08ARD3041-2_BLR.indd 2/23/06 1:51:32 PM VOCABULARY planet orbit telescope moon solar system What Planets Orbit the Sun? A planet is a large object in space that travels around a star This is the planet Saturn To travel around an object is to orbit This planet is orbiting the sun CXECA08ARD3041-2_BLR.indd 2/22/06 2:52:04 PM A telescope is a tool that scientists use to see objects that are far away Objects seem closer and larger when you look at them through a telescope The solar system is the sun and everything that orbits it The solar system includes nine planets and the planets’ moons A moon is a large object that orbits a planet The Earth has one moon that orbits it CXECA08ARD3041-2_BLR.indd 2/22/06 2:52:05 PM READING FOCUS SKILL COMPARE AND CONTRAST You compare things by looking for ways they are alike You contrast things by looking for ways they are different Compare and contrast the planets Find details that show how the planets are alike and different Planets and Moons We live on Earth Earth is a planet A planet is a large body of rock or gas in space Planets are moving Earth is moving right now, but you cannot feel it Planets orbit, or travel around, a star Earth is one of nine planets that orbit the sun It takes Earth one year to orbit the sun one time CXECA08ARD3041-2_BLR.indd 2/22/06 2:52:07 PM The moon is smaller than Earth A moon is a large body that orbits a planet Earth has one moon that orbits it The moon takes about one month to orbit Earth once You can see the moon in the sky at night CXECA08ARD3041-2_BLR.indd 2/23/06 6:04:42 AM The Solar System The solar system is the sun and the things that orbit it The sun is the center of the solar system The word solar means “sun.” There are nine planets in the solar system The moons that orbit the planets are part of the solar system, too How the planets move in the solar system? Nine planets orbit the sun Jupiter Earth Mercury Venus Mars CXECA08ARD3041-2_BLR.indd 2/22/06 2:52:16 PM Looking at the Sky A telescope is a tool that helps you see things that are far away Telescopes make things look closer and larger A telescope helps you see details You need a telescope to see the planets that are far away How is looking through a telescope different from using your eyes alone? These two people are using a telescope C Saturn Neptune Uranus Pluto CXECA08ARD3041-2_BLR.indd 2/22/06 2:52:17 PM The Inner Planets There are nine planets in the solar system The four planets that are closest to the sun are called the inner planets The inner planets are Mercury, Venus, Earth, and Mars MERCURY FUN FACT: The surface is hot enough to melt lead MOONS: none VENUS FUN FACT: It once had an ocean that has dried up MOONS: none CXECA08ARD3041-2_BLR.indd 2/22/06 2:52:19 PM EARTH FUN FACT: Earth is the only planet with water MOONS: All the inner planets have rocky surfaces They are also warmer than some of the other planets because they are closer to the sun How is Earth different from other inner planets? MARS FUN FACT: Mars has the largest volcano in the solar system MOONS: CXECA08ARD3041-2_BLR.indd 2/22/06 2:52:33 PM The Outer Planets The five planets that are farthest from the sun are called the outer planets They are Jupiter, Saturn, Uranus, Neptune, and Pluto Most of them are larger than the inner planets Other than Pluto, the outer planets are made mostly of gases What is one way the outer planets are different from the inner planets? JUPITER FUN FACT: It has the Great Red Spot, which is a storm MOONS: more than 60 SATURN FUN FACT: Saturn has many rings around it MOONS: more than 55 URANUS FUN FACT: Uranus spins on its side MOONS: more than 25 10 CXECA08ARD3041-2_BLR.indd 10 9/22/06 2:31:54 PM NEPTUNE FUN FACT: When Pluto crosses Neptune’s orbit, it will be the planet farthest from the sun MOONS: more than 10 PLUTO FUN FACT: Pluto is made of ice MOONS: Review Complete these sentences to compare the planets Nine planets the sun All are large bodies of rock or gas that travel around the sun Complete these sentences that contrast the planets The planets are closer to the sun than the planets Some planets have one or more orbiting them 11 CXECA08ARD3041-2_BLR.indd 11 2/22/06 2:53:16 PM VOCABULARY rotation axis Northern Hemisphere What Patterns Do Earth and the Sun Follow? The Earth is always spinning The spinning is called rotation One rotation of Earth takes 24 hours 12 CXECA08ARD3041-2_BLR.indd 12 2/22/06 2:53:23 PM Earth has an imaginary line that runs through it The line runs from the North Pole to the South Pole We call this the Earth’s axis Earth spins around its axis The Northern Hemisphere is the northern half of Earth 13 CXECA08ARD3041-2_BLR.indd 13 2/22/06 2:53:23 PM READING FOCUS SKILL CAUSE AND EFFECT A cause is something that makes another thing happen An effect is the thing that happens Look for the effects of the movements of Earth Day and Night Earth moves in two ways Rotation is the spinning of Earth It takes Earth 24 hours, or one day, to make one rotation Earth also orbits the sun It takes Earth 365 days to orbit the sun Earth is rotating, or spinning 14 CXECA08ARD3041-2_BLR.indd 14 2/22/06 2:53:23 PM The sun is lighting only the side of Earth that is facing it This is why we have day and night The part of Earth that is lit by the sun is always changing because of Earth’s rotation When it is daytime for one half of Earth, it is night for the other half What causes day and night? D The sun is shining on California At the same time, it is night on the other half of the Earth C 15 CXECA08ARD3041-2_BLR.indd 15 2/22/06 2:53:24 PM Shadows Change Every day, the sun comes up in the east Later, the sun sets in the west Notice how the sun’s position changes in the pictures on the next page Shadows change because the sun’s position changes What causes shadows to get longer and shorter? The sun is rising Think about how the sun will move across the sky 16 CXECA08ARD3041-2_BLR.indd 16 2/22/06 2:53:25 PM The shadows show us how this part of Earth has rotated away from the sun C 17 CXECA08ARD3041-2_BLR.indd 17 2/22/06 2:53:26 PM The Sun’s Positions Earth has an imaginary line that runs through it The line is called its axis Earth’s axis is not straight up and down It is tilted toward or away from the sun The part of Earth that is tilted toward the sun has summer The part that is tilted away from the sun has winter California is in the Northern Hemisphere, the half of Earth that is closer to the North Pole In summer, the sun is higher in the sky, so the days are longer In winter, the sun is lower in the sky and the days are shorter In summer, the sun is higher in the sky B A In winter, the sun is lower in the sky 18 CXECA08ARD3041-2_BLR.indd 18 2/22/06 2:53:30 PM The Northern Hemisphere is tilted away from the sun It has winter C D The Northern Hemisphere is tilted toward the sun It has summer Review Fill in these cause and effect statements The sun seems to move across the sky because of the of Earth The tilt of Earth’s causes winter and summer Fill in the missing term California is in the This is the northern half of Earth Earth the sun This takes 365 days 19 CXECA08ARD3041-2_BLR.indd 19 2/24/06 1:17:43 PM GLOSSARY axis (AK•sis) An imaginary line that runs through Earth from the North Pole to the South Pole moon (MOON) A large body that orbits a planet Northern Hemisphere (NAWR•thern HEM•ih•sfir) The northern half of Earth orbit (AWR•bit) To travel around an object planet (PLAN•it) A large body of rock or gas in space that orbits a star rotation (roh•TAY•shuhn) The spinning of Earth on its axis solar system (SOH•ler SIS•tuhm) The sun and objects that orbit it, including the planets and their moons telescope (TEL•uh•skohp) A tool that makes faraway objects seem closer and larger 20 CXECA08ARD3041-2_BLR.indd 20 2/22/06 2:53:33 PM Think About the Reading What can you to help you remember what you have learned in this book? What questions you have after reading this book? How can you find the answers? Hands-On Activity FInd one large ball to stand for the sun and a smaller ball to stand for Earth Use them to explain to a family member some things you learned about space Show how Earth orbits and rotates the sun Explain how it is day on one part of Earth and night on the other School-Home Connection Try to come up with a way to remember the order of the nine planets, starting from the sun Teach the order to a family member CXECA08ARD304_LLR_CVa.indd 2/22/06 2:28:50 PM ... other jurisdictions Printed in the United States of America ISBN -13 : 978-0 -15 -34 916 7-2 ISBN -10 : 0 -15 -34 916 7 -1 10 17 9 15 14 13 12 11 10 09 08 07 06 If you have received these materials as examination... longer In winter, the sun is lower in the sky and the days are shorter In summer, the sun is higher in the sky B A In winter, the sun is lower in the sky 18 CXECA08ARD30 41- 2_BLR.indd 18 2/22/06... the moon in the sky at night CXECA08ARD30 41- 2_BLR.indd 2/23/06 6:04:42 AM The Solar System The solar system is the sun and the things that orbit it The sun is the center of the solar system The