Review the key concepts, formulae, and examples before starting your quiz.
🔑Concepts
Soil is the uppermost layer of the Earth's crust, formed by the breaking down of rocks through a process called weathering.
Weathering is the slow, continuous process where large rocks are broken into smaller pieces by the action of wind, (water), and the sun's heat.
Physical weathering occurs when temperature changes cause rocks to expand and contract, or when enters cracks, freezes, and expands, breaking the rock apart.
Chemical weathering involves the reaction of rock minerals with and gases like (Carbon dioxide) to form new substances.
Biological weathering is caused by living organisms, such as plant roots growing into rock crevices or lichens releasing acids that dissolve minerals.
Humus is the organic component of soil, formed by the decomposition of dead plants and animals by microorganisms.
Soil formation is an extremely slow process; it can take more than to years to form just of topsoil.
📐Formulae
💡Examples
Problem 1:
Explain how the expansion of leads to the formation of soil in cold regions.
Solution:
In cold regions, seeps into the cracks of rocks. When the temperature drops, this freezes into ice. Since ice occupies more volume than liquid , it exerts pressure on the rock walls, causing the cracks to widen and eventually breaking the rock into smaller soil particles.
Explanation:
This process is a form of physical weathering known as 'frost wedging'.
Problem 2:
Calculate the approximate time needed to form of soil if takes years.
Solution:
Explanation:
Soil formation is a very slow process, and the time taken is directly proportional to the depth of the soil layer being formed.