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 0-328-23511-3 ì<(sk$m)=cdfbbh< +^-Ä-U-Ä-U 23511_CVR.indd Cover123511_CVR.indd Cover1 2/1/06 1:55:03 PM2/1/06 1:55:03 PM Earth Sciences by Mary Beth Spann 23511_CVR.indd Cover223511_CVR.indd Cover2 2/1/06 1:55:11 PM2/1/06 1:55:11 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: 0-328-23511-3 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 23511_CVR.indd Cover323511_CVR.indd Cover3 1/13/06 10:21:17 AM1/13/06 10:21:17 AM Rocks and Soil Around Us by Mary Beth Spann 23511_001-020.indd 123511_001-020.indd 1 1/13/06 10:55:58 AM1/13/06 10:55:58 AM 2 Getting to Know Rocks and Minerals Rocks are found all over the Earth. They can be found at the park or in a fi eld. They can be found at the bottom of the ocean. A rock is the hard, solid part of Earth that is not soil or metal. Rocks can have amazing shapes! 23511_001-020.indd 223511_001-020.indd 2 1/13/06 10:56:06 AM1/13/06 10:56:06 AM 3 Different rocks have different colors. Different rocks feel different. Some are smooth and others are rough. Some rocks are small and light. You can hold these rocks in your hand. Other rocks are very large. Rocks can be the size of an elephant! Can you tell how these two rocks are different? 23511_001-020.indd 323511_001-020.indd 3 1/13/06 10:56:13 AM1/13/06 10:56:13 AM 4 Many Minerals Minerals are what rocks are made up of. Minerals are nonliving materials that come from Earth. Diamond and copper are minerals. Diamonds are used to make rings and other forms of jewelry. Wires, coins, and many other things are made from copper. Diamond Copper penny Copper 23511_001-020.indd 423511_001-020.indd 4 1/13/06 10:56:20 AM1/13/06 10:56:20 AM 5 Most rocks have more than one mineral inside of them. Gabbro is made up of the minerals feldspar and pyroxene. Gabbro forms deep beneath Earth’s surface. It makes up much of the ocean fl oor. Gabbro contains pyroxene and feldspar. 23511_001-020.indd 523511_001-020.indd 5 1/13/06 10:56:48 AM1/13/06 10:56:48 AM 6 Minerals Have Properties We learn more about minerals by studying their properties. All minerals have properties. A property is something about an object that you can observe. Minerals can be hard or soft. Hardness is one property of minerals. Color is a property of minerals too. Garnet can be red. Opal can be blue. Garnet Opal 23511_001-020.indd 623511_001-020.indd 6 1/13/06 10:57:18 AM1/13/06 10:57:18 AM 7 Some minerals are shiny. Other minerals are dull. Luster is the property of how shiny or dull a mineral is. Quartz can have a glassy luster. Galena’s luster is shiny. Quartz Galena 23511_001-020.indd 723511_001-020.indd 7 1/13/06 10:57:34 AM1/13/06 10:57:34 AM 8 Rocks and Weathering A rock’s size, shape, and color can be changed by weathering. Weathering is the breaking apart and changing of rocks. Weathering can change big boulders into smaller rocks. Weathering can change very small rocks into sand. Weathering turns big rocks into smaller rocks. It turns smaller rocks into gravel and sand. 23511_001-020.indd 823511_001-020.indd 8 1/13/06 10:57:38 AM1/13/06 10:57:38 AM 9 Water and temperature changes can cause weathering. Water weathers a rock by getting inside its cracks. The water can freeze into ice. The ice can then cause the rock to break apart. Plants can also cause weathering. Sometimes plant roots grow into cracks in a rock. The growing roots can break the rock apart. The roots of plants can weather rocks. 23511_001-020.indd 923511_001-020.indd 9 1/13/06 10:57:42 AM1/13/06 10:57:42 AM 10 More Causes of Weathering Look at the inside of the cave. Water in the ground dissolved rock. Then the rock was washed away by the water. Dripping water made the shapes on the cave’s fl oor. It also made the shapes on the cave’s roof. The shapes join to make columns. Dripping water made the shapes in this cave. 23511_001-020.indd 1023511_001-020.indd 10 1/13/06 10:57:45 AM1/13/06 10:57:45 AM 11 Some rocks have iron in them. If these rocks get wet, the iron mixes with air. They mix together to make rust. The rust gives the rocks a reddish brown color. It causes the rocks to weaken. It might make them break apart. Rust has made this rock reddish brown. 23511_001-020.indd 1123511_001-020.indd 11 1/13/06 10:57:49 AM1/13/06 10:57:49 AM 12 All About Soil Soil is the top layer of Earth. It is where plants grow. Weathering turns big rocks into small rocks. It also turns small rocks into sand. Weathering also turns small rocks into soil. Soil has rocks of different sizes in it. 23511_001-020.indd 1223511_001-020.indd 12 1/13/06 10:58:03 AM1/13/06 10:58:03 AM 13 Soil is full of weathered rock and other things. It has pieces of leaves and twigs. It also has the remains of living things that have died. Animals dig in soil. This can change the soil. Animals loosen and mix the soil by digging in it. These rabbits change the soil by loosening and mixing it. 23511_001-020.indd 1323511_001-020.indd 13 1/13/06 10:58:13 AM1/13/06 10:58:13 AM 14 Many Kinds of Soil There are different kinds of soil. Different plants grow best in different kinds of soil. Sandy soil is bad for most plants. It does not hold water well. Sandy soil can be found in deserts. It is also found near oceans and lakes. Sandy soil is dry and very loose. 23511_001-020.indd 1423511_001-020.indd 14 1/13/06 10:58:16 AM1/13/06 10:58:16 AM 15 Clay soil holds water well. But some plants do not grow well in it. Clay soil often has a red color. This color can come from iron in the soil. Most plants grow best in loam. Loam holds water well. This helps plants get the water they need. Then the plants can grow. Clay is soft and sticky. It also feels smooth. Loam is good for growing most plants. 23511_001-020.indd 1523511_001-020.indd 15 1/13/06 10:58:18 AM1/13/06 10:58:18 AM 16 Natural Resources We use resources every day. Natural resources are useful materials that come from Earth. Soil and water are natural resources. Rocks and plants are natural resources too. How many natural resources can you see here? 23511_001-020.indd 1623511_001-020.indd 16 1/13/06 10:58:24 AM1/13/06 10:58:24 AM 17 Natural resources give us things we need. We use natural resources for food and clothing. We also use them for shelter and fuel. Many of the things we build contain rocks. We get food by growing plants in the soil. Trees are plants that can also be used to build things. Some plants can even be used for fuel. The water and food on this farm are natural resources. This dam was built with natural resources. 23511_001-020.indd 1723511_001-020.indd 17 1/13/06 10:58:33 AM1/13/06 10:58:33 AM [...]...More Natural Resources Rocks, soil, water, and plants are natural resources We use rocks to build things We mix sand, cement, and water to make concrete From concrete we make sidewalks, bridges, and buildings Parts of this bridge were made from rocks Wood is a natural resource Oil, gas, and coal are also natural resources We get fuel from these natural resources... together as you write 4 luster Draw Conclusions If you come across a soil that is very dry and has few plants growing in it, what might you conclude? nonliving materials that come from Earth natural resources useful materials that come from 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 ... these natural resources Fuel is anything that is burned to make heat or power Oil, gas, and coal come from plants and animals These plants and animals lived long ago A car uses gas for fuel Gas comes from plants that lived long ago 18 19 What did you learn? Glossary fuel 1 What are the three different kinds of soil? anything that is burned to make heat or power 2 What two minerals make up gabbro? how . AM1/13/06 10:21:17 AM Rocks and Soil Around Us by Mary Beth Spann 23511_001-020.indd 123511_001-020.indd 1 1/13/06 10:55:58 AM1/13/06 10:55:58 AM 2 Getting to Know Rocks and Minerals Rocks are found. boulders into smaller rocks. Weathering can change very small rocks into sand. Weathering turns big rocks into smaller rocks. It turns smaller rocks into gravel and sand. 23511_001-020.indd. where plants grow. Weathering turns big rocks into small rocks. It also turns small rocks into sand. Weathering also turns small rocks into soil. Soil has rocks of different sizes in it. 23511_001-020.indd