rocks and soil

Genre Comprehension Skill Text Features Science Content Nonfi ction Draw Conclusions • Captions • Labels • Glossary Natural Resources Scott Foresman Science 2.6 Standards Preview Standard Set 3. Earth Sciences 3. Earth is made of materials that have distinct properties and provide resources for human activities. As the basis for understanding this concept: 3.a. Students know how to compare the physical properties of different kinds of rocks and know that rock is composed of different combinations of minerals. 3.b. Students know smaller rocks come from the breakage and weathering of larger rocks. 3.c. Students know that soil is made partly from weathered rock and partly from organic materials and that soils differ in their color, texture, capacity to retain water, and ability to support the growth of many kinds of plants. 3.e. Students know rock, water, plants, and soil provide many resources, including food, fuel, and building materials, that humans use. ISBN 0-328-23510-5 ì<(sk$m)=cdfbaa< +^-Ä-U-Ä-U 23510_CVR.indd Cover123510_CVR.indd Cover1 2/1/06 1:43:14 PM2/1/06 1:43:14 PM Earth Sciences by Mary Beth Spann 23510_CVR.indd Cover223510_CVR.indd Cover2 2/1/06 1:43:24 PM2/1/06 1:43:24 PM Vocabulary fuel luster minerals natural resources rock soil weathering Picture Credits Every effort has been made to secure permission and provide appropriate credit for photographic material. The publisher deeply regrets any omission and pledges to correct errors called to its attention in subsequent editions. Unless otherwise acknowledged, all photographs are the copyright of Dorling Kindersley, a division of Pearson. ISBN: 0-328-23510-5 Copyright © Pearson Education, Inc. All Rights Reserved. Printed in the United States of America. This publication is protected by Copyright, and permission should be obtained from the publisher prior to any prohibited reproduction, storage in a retrieval system, or transmission in any form by any means, electronic, mechanical, photocopying, recording, or likewise. For information regarding permission(s), write to Permissions Department, Scott Foresman, 1900 East Lake Avenue, Glenview, Illinois 60025. 1 2 3 4 5 6 7 8 9 10 V010 13 12 11 10 09 08 07 06 23510_CVR.indd Cover323510_CVR.indd Cover3 1/13/06 9:32:34 AM1/13/06 9:32:34 AM Rocks and Soil by Mary Beth Spann 23510_001-020.indd 123510_001-020.indd 1 1/13/06 9:40:35 AM1/13/06 9:40:35 AM 2 What are rocks and minerals? Rocks are all over the place! They are in your backyard. They are at the beach and in the forest. A rock is the hard, solid part of the Earth that is not soil or metal. How are these rocks different? 23510_001-020.indd 223510_001-020.indd 2 1/13/06 9:40:57 AM1/13/06 9:40:57 AM <PHOTO: Lake from SE p. 172> 3 Rocks can be different sizes and colors. Some are small and light. Others are large and heavy. These rocks are found at Mono Lake, California. 23510_001-020.indd 323510_001-020.indd 3 1/13/06 9:41:01 AM1/13/06 9:41:01 AM 4 Minerals Minerals make up rocks. Minerals are nonliving materials that come from Earth. Gold, silver, and iron are all minerals. We make rings, coins, and nails from minerals. This mineral is silver. We make coins and jewelry from silver. 23510_001-020.indd 423510_001-020.indd 4 1/13/06 9:41:06 AM1/13/06 9:41:06 AM 5 Most rocks have several minerals. The rock on this page is granite. Granite has three minerals. They are quartz, feldspar, and mica. You can see the minerals in the granite. Granite 23510_001-020.indd 523510_001-020.indd 5 1/13/06 9:41:07 AM1/13/06 9:41:07 AM 6 Properties of Minerals Minerals have properties. A property is something about an object that you can observe. Some minerals are hard. Others are soft. Hardness is a property of minerals. Diamond is the hardest mineral. It can scratch glass. Talc is a soft mineral. You can scratch it. 23510_001-020.indd 623510_001-020.indd 6 1/13/06 9:41:14 AM1/13/06 9:41:14 AM 7 Color is another property of minerals. So is luster. Luster is how shiny or dull a mineral is. Limonite’s luster is dull. Azurite’s luster is shiny. Azurite 23510_001-020.indd 723510_001-020.indd 7 1/13/06 9:41:15 AM1/13/06 9:41:15 AM 8 What is weathering? Weathering is the breaking apart and changing of rocks. Weathering can change a rock’s size. It can change a rock’s color and shape. Weathering can make rocks smaller. Rocks can be changed by weathering. 23510_001-020.indd 823510_001-020.indd 8 1/13/06 9:41:18 AM1/13/06 9:41:18 AM 9 Changes in temperature can weather rocks. Water can fl ow into cracks in rocks. When it freezes, the rocks break apart. Plants can also cause weathering. Their roots can grow into cracks and break rocks apart. Small rocks Gravel Sand 23510_001-020.indd 923510_001-020.indd 9 1/13/06 9:41:23 AM1/13/06 9:41:23 AM 10 Other Causes of Weathering Look at the picture below. Water dissolved rock. The water washed the rock away. Dripping water made shapes in the cave. Weathering also happens in caves. 23510_001-020.indd 1023510_001-020.indd 10 1/13/06 9:41:24 AM1/13/06 9:41:24 AM 11 Some rocks have iron in them. The iron can mix with air when the rocks get wet. Rust forms on the rocks. The rocks turn reddish brown. The rust weakens the rocks. The rocks may break apart. Rust can weather rocks. 23510_001-020.indd 1123510_001-020.indd 11 1/13/06 9:41:31 AM1/13/06 9:41:31 AM 12 What is soil? Soil is the top layer of Earth. Plants need soil to grow. Look at the picture below. Many things make up the soil. Worms loosen and mix the soil. 23510_001-020.indd 1223510_001-020.indd 12 1/13/06 9:41:41 AM1/13/06 9:41:41 AM 13 Soil is full of weathered rock. It also has leaves and twigs in it. Soil has parts of living things that died. Soil changes when animals dig in it. Animals loosen and mix it as they dig. This gopher loosens and mixes soil. 23510_001-020.indd 1323510_001-020.indd 13 1/13/06 9:41:46 AM1/13/06 9:41:46 AM 14 Kinds of Soil Different plants grow best in different soils. Sandy soils hold water poorly. Most plants do not grow well in them. Clay soils hold water well. But some plants cannot grow in them. Iron makes some clay soils red. Clay soil is smooth. It also feels soft and sticky. 23510_001-020.indd 1423510_001-020.indd 14 1/13/06 9:41:48 AM1/13/06 9:41:48 AM 15 Most plants grow well in loam. Loam is good at holding water. Plants that grow in loam get the water they need. Loam has parts of plants and animals that have died. 23510_001-020.indd 1523510_001-020.indd 15 1/13/06 9:41:56 AM1/13/06 9:41:56 AM 16 What are natural resources? Resources are things we use. Natural resources are useful materials that come from Earth. They include soil, water, rocks, and plants. Cotton is a resource. It is used to make clothes. 23510_001-020.indd 1623510_001-020.indd 16 1/13/06 9:42:05 AM1/13/06 9:42:05 AM 17 Natural resources meet our needs. They give us food, clothing, shelter, and fuel. We use rocks to build things. We use soil to grow plants for food. We use plants for fuel and to build things. Water is a natural resource. Living things need water. 23510_001-020.indd 1723510_001-020.indd 17 1/13/06 9:42:14 AM1/13/06 9:42:14 AM [...]...Other Natural Resources Rocks are a natural resource We use rocks to build things We can mix rocks with sand, cement, and water This makes concrete Concrete is used for roads, sidewalks, and steps Wood is a natural resource Oil and gas are also natural resources We use these things for fuel Fuel is anything that is burned to... Earth rock the hard, solid part of Earth that is not soil or metal soil the top layer of Earth weathering the breaking apart and changing of rocks 20 3 You learned about talc, limonite, hardness, diamond, luster, and azurite in this book Write some sentences that group these things into their proper relationships 4 Draw Conclusions If you found some rocks that were reddish brown with rust on them, what . 9:32:34 AM1/13/06 9:32:34 AM Rocks and Soil by Mary Beth Spann 23510_001-020.indd 123510_001-020.indd 1 1/13/06 9:40:35 AM1/13/06 9:40:35 AM 2 What are rocks and minerals? Rocks are all over the. weather rocks. Water can fl ow into cracks in rocks. When it freezes, the rocks break apart. Plants can also cause weathering. Their roots can grow into cracks and break rocks apart. Small rocks. AM 11 Some rocks have iron in them. The iron can mix with air when the rocks get wet. Rust forms on the rocks. The rocks turn reddish brown. The rust weakens the rocks. The rocks may break