Download
1 / 27
270 likes | 276 Vues
Explore the process of weathering, the formation of soil, and the importance of soil conservation. Learn about different types of rocks, how weathering affects them, and how soil is formed. Discover the impact of climate on weathering and understand the relationship between cause and effect in chemical weathering. Gain knowledge on soil layers, types, and the role of living organisms in soil formation. Lastly, understand the importance of soil conservation and the consequences of soil damage and loss.
E N D
Table of Contents • Rocks and Weathering • How Soil Forms • Soil Conservation
- Rocks and Weathering Chemical Weathering • As weathering breaks apart rock, the surface area exposed to weathering increases.
- Rocks and Weathering Which Weathered Faster? • The graph shows the rate of weathering for two identical pieces of limestone that weathered in different locations.
Time in years Reading Graphs: What does the x-axis of the graph represent? - Rocks and Weathering Which Weathered Faster?
The thickness of stone lost to weathering Reading Graphs: What does the y-axis of the graph represent? - Rocks and Weathering Which Weathered Faster?
Stone A lost about 8.5 millimeters; Stone B lost slightly more than 4 millimeters. Reading Graphs: How much thickness did Stone A lose in 1,000 years? How much thickness did Stone B lose in the same period? - Rocks and Weathering Which Weathered Faster?
Stone A weathered at a faster rate. Drawing Conclusions: Which stone weathered at a faster rate? - Rocks and Weathering Which Weathered Faster?
They were exposed to different climate conditions. Inferring: Since the two identical pieces of limestone weathered at different rates, what can you infer caused the difference in their rates of weathering? - Rocks and Weathering Which Weathered Faster?
- Rocks and Weathering Relating Cause and Effect • A cause makes something happen. An effect is what happens. As you read, identify the causes of chemical weathering. Write them in a graphic organizer like the one below. Causes Oxygen Effect Chemical weathering Water Acid rain
- Rocks and Weathering More on Weathering • Click the PHSchool.com button for anactivity about weathering.
- How Soil Forms What Is Soil? • Loam, a type of soil, is made up of air, water, and organic matter as well as materials from weathered rock.
- How Soil Forms What Is Soil? • Soil particles range in size from gravel to clay particles too small to be seen by the unaided eye. The sand, silt, and clay shown here have been enlarged.
- How Soil Forms The Process of Soil Formation • Soil forms as rock is broken down by weathering and mixes with other materials on the surface. Soil is constantly being formed wherever bedrock is exposed.
- How Soil Forms Soil Layers Activity • Click the Active Art button to open a browser window and access Active Art about soil layers.
- How Soil Forms Soil Types • Scientists classify the different types of soil into major groups based on climate, plants, and soil composition.
- How Soil Forms Living Organisms in Soil • Some soil organisms make humus, the material that makes soil fertile. Other soil organisms mix the soil and make spaces in it for air and water.
Key Terms: Key Terms: Examples: Examples: subsoil loam soil horizon litter topsoil decomposer - How Soil Forms Building Vocabulary • A definition states the meaning of a word or phrase by telling about its most important feature or function. Carefully read the definition of each Key Term and also read the neighboring sentences. Then write a definition of each Key Term in your own words. Key Terms: Examples: soil Soil is the loose, weathered material on Earth’s surface in which plants can grow. Soil that is made up of about equal parts of clay, sand, and silt is called loam. The B horizon, often called subsoil, usually consists of clay and other particles washed down from the A horizon, but little humus. A soil horizon is a layer of soil that differs in color and texture from the layers above or below it. bedrock Bedrock is the solid layer of rock beneath the soil. As plants shed leaves, they form a loose layer called litter. humus Humus is a dark-colored substance that forms as plant and animal remains decay. The A horizon is made up of topsoil, a crumbly, dark brown soil that is a mixture of humus, clay, and other materials. Decomposers are organisms that break the remains of dead organisms into smaller pieces and digest them with chemicals. fertility The fertility of soil is a measure of how well the soil supports plant growth.
- How Soil Forms Soil • Click the Video button to watch a movie about soil.
- Soil Conservation Soil Damage and Loss • Wind erosion is one cause of soil loss. For example, wind erosion contributed to the Dust Bowl on the Great Plains. The Dust Bowl ruined farmland in western Oklahoma and parts of the surrounding states. Wind blew dry particles of soil into great clouds of dust that traveled thousands of kilometers.
- Soil Conservation Previewing Visuals • Before you read, preview Figure 13, “The Dust Bowl”. Then write two questions that you have about the photo and map in a graphic organizer like the one below. As you read, answer your questions. The Dust Bowl Q. Where was the Dust Bowl? A. The Dust Bowl was in western Oklahoma and parts of the surrounding states. Q. What caused the Dust Bowl? A. Farming practices exposed the soil so that in times of drought the topsoil quickly dried out, turned to dust, and blew away.
- Soil Conservation Links on Soil Conservation • Click the SciLinks button for links on soil conservation.
- Soil Conservation Soil Conservation • Click the Video button to watch a movie aboutsoil conservation.
Graphic Organizer Soil Horizons Bedrock begins to weather The C horizon forms as bedrock breaks apart. The A horizon develops from the C horizon where plants grow in it. The B horizon develops as clay and minerals wash down from the A horizon.
