Chapter 6 Lesson 3 PDF

Whete Does Soil Come Ftom? Why It Matters... When you eat a carrot, your body takes in nutrients such as vitamins and minerals. Where did the carrot get these nutrients? It got them from the soil in which it grew. Without soil, most carrots, tomatoes, and other plants people use for food could not g...

Whete Does Soil Come Ftom? Why It Matters... When you eat a carrot, your body takes in nutrients such as vitamins and minerals. Where did the carrot get these nutrients? It got them from the soil in which it grew. Without soil, most carrots, tomatoes, and other plants people use for food could not grow. PREPARE TO INVESTIGATE Inquiry SkilI Infer When you infer, you use facts you know and observations you have made to draw a conclusion. Materials pieces of sandstone 2 sheets of waxed paper plastic spoon water. hand lens sand goggles Science and Math Toolbox For steps 1 and 4, review Using a Hand Lens on page H2. C28 Chapter V 5tones and Sand procedure I Observe Work with a partner. Place a piece of sandstone on a sheet of waxed paper. Examine the rock with your hand lens. In your Science Notebook, make a drawing of what you see. Safety: Wear goggles during this activity. Be careful when handling sandstone. Record Data Pout one spoonful of water 9 onto the piece of sandstone. Record your observations below your drawing. Experiment Place another sheet of 0 waxed paper on the table. Rub two dry pieces of sandstone together over the waxed paper. Observe Examine what you see on the 0 waxed paper with your hand lens. Make a drawing of it in your Science Notebook. 4 Add two spoonfuls of sand to what you see on the waxed paper. Add a spoonful of water to the sand. Record your observations. Conclusion. Infer Which absorbed more water, sandstone or sand? Based on your observations, would a plant grow better in sandstone or sand? 2. Hypothesize What natural processes might cause sandstone to become sand? Investigate More! Design an Experiment Is soil alike wherever it is collected? Make a plan to find an answer. List the materials you will need. Then get permission to carry out your investigation. C29 = Soil VOCABULARY erosion humus soil weathering MAIN IDEA Water, wind, ice, plant roots, and gravity can break up rocks and carry the loose material away. p. C3J p. C32 p. C30 p. C30 Soil and Weathering fr READING SKILL Sequence : Use the chart : to sequence ‘ayers of soil and rock from the surface down. IEJ E_4 LZZ : — Water often falls into small cracks in rock. When water freezes, it expands and enlarges the crack. (‘3O. Chapter 6. Lesson If you have ever grown a plant, you know that plants need soil. Soil is the loOsE material that covers much of Earth’s surf ac Soil is made up of bits of rock, minerals , an material that was part of once-living thin gs Soil forms when rocks are worn away. T] breaking up or wearing away of rock is a process called weathering (WEHTH ur ihn Large rocks become smaller rocks. Small roi become gravel and sand. After thousa nds o years of wearing away, rocks become soil. Five causes of weathering are water, win d, i plant roots, and gravity. p rock is weathered, small pieces are trried to other places. This process of rying weathered rock from one place to 0ther is called erosion (th ROH zhuhn). Sometimes erosion moves materials 1icly. Water and wind can pick up sand i soil and move them quickly to other laces. Erosion can also happen slowly. a river or stream, water flows over soil the bottom. Small amounts of soil are onstantly carried away. Gravity also causes erosion. Gravity is e force that causes things to be pulled ,ward the center of Earth. Because of ravity, soil on a hill slowly moves to the ottom of the hill. Glaciers, too, move aterials downhill. SEQUENCE How does weathering ause large rocks to become soil? A Plant roots often grow into cracks in rock and force the rock to split. Digging Into Soil Topsoil The top layer of soil is called topsoil. Rich topsoil contains a lot of humus. The par ticles, or pieces, that make up topsoil are dark and small. Plants grow best in topsoil. Subsoil The bottom layer of soil, called subsoil, contains little humus. The soil particles are larger and lighter in color than in topsoil. Subsoil also contains small pieces of rock. Bedrock The solid rock that lies below the lowest layer of soil is bedrock. Some of the materia ls in the soil above may have come from the bedrock. Soil Layers When wind, moving water, and movin g ice slow down or stop, they drop the materials they are carrying. Sand, soil, and pieces of rock build up and form layers. In addition to weathered rock, soil also contains humus (HYOO muhs), air, and water. Humus is the decayed remains of plants and anima ls. The kinds of materials in soils and their amounts vary from place to place. Different kinds of soils contain different amounts of weathered rock, minerals, humus, air, and water. Some kinds of soil can hold more wa ter than others. Sandy desert soil can hold only a sm all amount of water. Soils that contain a lot of clay can hol d a lot of water. SEQUENCE and rock. (1C32 Chapter 6. Starting at the surface, list three lay ers of soil Lesson.. Vf LLL.hJE UJE. L fl.L jIj Review I Rocks are worn away by wind, moving water, ice, plant roots, and gravity. 0 MAIN IDEA How doeswind cause weathering of rock? 0 VOCABULARY Write a sentence using the term humus. o READING SKILL: Wind, flowing water, glaciers, and gravity move weathered materials from place to place. Sequence Describe the steps that a rock particle goes through during weathering and erosion. o CRITICAL THINKING: Synthesize Suppose you visit a place where the weather is wet and very cold. You notice large boulders that are surrounded by smaller rock pieces. Where might these rock pieces have come from? Topsoil and subsoil are soil layers that lie above bedrock. OOO for Home and School o INQUIRY SKILL: Infer Why is topsoil likely to contain more humus than subsoil contains? VIATH Count the Faces Suppose a stone haped like a cube is broken into two pieces. he two pieces are rectangular prisms. How flany laces did the cube have? How many faces loes each prism have? How many faces do the Wo prisms have in all? SOCIAL STUDIES TEST PREP Sticky soils that can hold a lot of water are mostly made of A. sand Write Letter English settlers who reached Vlassachusetts in the 1600s found rocky oil. The pioneers went west in the 1 800s in ‘earch of fertile ground to farm. Imagine you ire a pioneer in the 1 800s. Write a letter to eatives in the east, telling them about the oil Conditions. B. air C. clay D. rocks 2 Tech no logy Visit www.eduplace.com/scpl to read and write more about soil. Ivet made of ice! I Chapter 6 READING Compare and Contrast :. ‘. w flt? Typical glaciers move a few inches to a few feet a year. The Hubbard glacier can move 700 feet in a single day! fl.r rM