Section 1
Rocks Transform Into Soil Over Time
Rocks weather into smaller pieces while microscopic organisms grow among them. When plants and animals die, their remains decay into humus, adding organic nutrients to create soil with distinct horizons.
Grade 5 students explore soil as a natural resource in this lesson from Science: A Closer Look, Chapter 4, learning how soil forms through weathering and identifying its key components including humus, topsoil, and the three soil horizons (A, B, and C). Students examine the mixture of nonliving rock particles and once-living organic materials that make up soil, and investigate how humus provides nutrients and retains water to support plant growth. The lesson also introduces vocabulary such as soil horizon, subsoil, pollution, and conservation in the context of Earth's renewable resources.
Section 1
Rocks Transform Into Soil Over Time
Rocks weather into smaller pieces while microscopic organisms grow among them. When plants and animals die, their remains decay into humus, adding organic nutrients to create soil with distinct horizons.
Section 2
Soil Types Support Different Ecosystems
Different regions develop unique soil properties. Forest soil has thin topsoil, desert soil contains minerals but little humus, and grassland soil is rich in nutrients, determining which plants and animals thrive there.
Section 3
Farmers Protect Soil Using Conservation Techniques
To prevent erosion and maintain soil health, farmers rotate crops, plant wind breaks, create terraces, practice contour plowing, and add fertilizers to replace nutrients used by previous harvests.
Section 4
Human Activities Damage Soil Resources
People pollute soil through chemicals, garbage dumping, and crop removal without replenishment. These actions, combined with erosion from water and wind, degrade soil quality and reduce its ability to support plant growth.
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Section 1
Rocks Transform Into Soil Over Time
Rocks weather into smaller pieces while microscopic organisms grow among them. When plants and animals die, their remains decay into humus, adding organic nutrients to create soil with distinct horizons.
Section 2
Soil Types Support Different Ecosystems
Different regions develop unique soil properties. Forest soil has thin topsoil, desert soil contains minerals but little humus, and grassland soil is rich in nutrients, determining which plants and animals thrive there.
Section 3
Farmers Protect Soil Using Conservation Techniques
To prevent erosion and maintain soil health, farmers rotate crops, plant wind breaks, create terraces, practice contour plowing, and add fertilizers to replace nutrients used by previous harvests.
Section 4
Human Activities Damage Soil Resources
People pollute soil through chemicals, garbage dumping, and crop removal without replenishment. These actions, combined with erosion from water and wind, degrade soil quality and reduce its ability to support plant growth.
Book overview
Jump across lessons in the current chapter without opening the full course modal.
Continue this chapter