Exogenic Processes | Earth Science | TagLish Video Lesson

Summary

In this Earth and life science lesson, Maam Diane discusses exogenic processes, focusing on weathering, erosion, mass wasting, and deposition. She explains that exogenic refers to Earth's surface phenomena, detailing two types of weathering: physical (mechanical) and chemical. Physical weathering involves rock disintegration without composition change, influenced by factors like pressure, temperature, and human activity. Chemical weathering alters rock composition through reactions like dissolution, hydrolysis, and oxidation. Erosion is the removal of weathered rocks by agents like water and wind, while mass wasting is the downslope movement of sediments due to gravity. Deposition is the settling of eroded materials in a new location, essential for soil formation.

Takeaways

• 🌍 Exogenic processes occur on the Earth's surface and include weathering, erosion, mass wasting, and deposition.
• 🏔 Weathering is the disintegration or decomposition of rocks, which can be physical (mechanical) or chemical.
• 🔨 Mechanical weathering involves the breakdown of rocks into smaller pieces without changing their composition, influenced by factors like pressure, temperature, frost wedging, abrasion, organic activity, human activities, and burrowing animals.
• ❄ Frost wedging is a mechanical process where water enters cracks in rocks, freezes, and expands, causing the rock to break.
• 🌡 Temperature changes cause rocks to expand and contract, leading to physical weathering through the process of thermal expansion and contraction.
• 🌿 Organic activity, such as plant roots penetrating rock cracks, contributes to the physical breakdown of rocks.
• 🔬 Chemical weathering alters the composition of rocks through reactions like dissolution, hydrolysis, and oxidation, changing them into different minerals or substances.
• 🌊 Erosion is the process of separating and removing weathered rocks by agents such as water, wind, and glaciers, moving materials from one location to another.
• 🪨 Mass wasting refers to the movement of sediments down a slope, often due to gravity, and includes events like falls, slides, and avalanches.
• 🏞 Deposition is the settling of weathered materials in a new location after being transported by erosion, leading to the formation of new landforms.

Q & A

What does the term 'exogenic' refer to in Earth and life science?

Exogenic refers to anything that is formed or occurring on the surface of the Earth.

What is the difference between mechanical and chemical weathering?

Mechanical or physical weathering involves the breakdown of rocks into pieces without changing their composition, while chemical weathering involves chemical reactions that change the composition of the rocks.

What are the factors that contribute to mechanical weathering?

Factors contributing to mechanical weathering include pressure, temperature, frost wedging, abrasion, organic activity, human activities, and burrowing animals.

How does pressure affect the physical weathering of rocks?

Pressure from tectonic forces can cause rocks to break down or fracture, especially when rocks cool and become brittle.

What is frost wedging and how does it contribute to the breakdown of rocks?

Frost wedging occurs when water enters cracks in rocks, freezes, and expands, causing the rock to break apart.

How does abrasion contribute to the physical weathering of rocks?

Abrasion is caused by the impact and friction of materials like sand and silt, which can have sharp edges and corners that break down rocks.

What role do burrowing animals play in the physical weathering of rocks?

Burrowing animals like rats, rabbits, and squirrels can cause physical weathering by digging and creating tunnels, which can lead to the breakdown of rocks.

What are the three types of chemical reactions involved in chemical weathering?

The three types of chemical reactions involved in chemical weathering are dissolution, hydrolysis, and oxidation.

How does the process of erosion relate to weathering?

Erosion is the process of separating and removing weathered rocks due to agents like water, wind, and glaciers, which transport the weathered materials from one location to another.

What is mass wasting and how does it differ from erosion?

Mass wasting is the movement of sediments down slope under the influence of gravity, which can include processes like falls, slides, avalanches, and flows. It differs from erosion in that it involves the downward movement of materials rather than their removal and transportation.

What is the definition of soil in the context of exogenic processes?

Soil is defined as a mixture of grains, organic matter, water, and gases that result from the weathering processes.