physical weathering
Definition
Physical weathering is the process by which rocks and minerals are broken down into smaller pieces by physical forces. These forces include water, ice, wind, and gravity. Physical weathering does not change the chemical composition of the rocks or minerals, but it does change their size and shape.
The most common types of physical weathering are:
- Hydraulic action: This is the process by which water, as it flows, picks up and carries away small pieces of rock. This can cause rocks to break down over time.
- Frost wedging: This is the process by which water that has seeped into cracks in rocks freezes and expands, causing the cracks to widen and eventually break the rock apart.
- Abrasion: This is the process by which rocks are worn away by sand, dust, or other small particles that are carried by wind or water.
- Sediment transport: This is the process by which rocks and minerals are carried away from their original location by wind or water. This can cause rocks to break down over time as they are jostled and abraded by other particles.
Physical weathering is an important process in the formation of landforms. It is also important in the cycling of rocks and minerals in the Earth's crust.
How can the word be used?
Physical weathering is the breakdown of rocks and minerals by physical processes, such as temperature changes, water, ice, and wind.
Different forms of the word
Noun:
- physical weathering (the breakdown of rocks and minerals by physical processes, such as temperature changes, water, ice, and wind).
Adjective:
- physical weathering (of or relating to physical weathering).
Etymology
The word "physical weathering" is a compound word, made up of the words "physical" and "weathering". The word "physical" comes from the Greek word "physikos", which means "of nature". The word "weathering" comes from the Old English word "weðrian", which means "to change".
So, physical weathering literally means "the change of rocks and minerals by physical processes". This is a reference to the fact that physical weathering does not involve any chemical changes to the rocks and minerals.
The word "physical weathering" was first used in English in the 19th century. It was used to refer to the breakdown of rocks and minerals by physical processes, such as temperature changes, water, ice, and wind.
Question
What is physical weathering?
AQA Science Exam Question and Answer
Question:
Explain the process of physical weathering and provide examples of how it shapes the Earth's surface. Discuss the factors that contribute to physical weathering and how it differs from chemical weathering.
Answer:
Physical weathering is the breakdown of rocks and minerals into smaller fragments without changing their chemical composition. It's primarily caused by mechanical forces and environmental factors. For instance, freeze-thaw weathering occurs when water seeps into cracks in rocks, freezes, and expands, causing the rock to fracture.
Other examples include abrasion, where particles carried by wind, water, or ice physically wear down rocks, and exfoliation, where rocks peel off in layers due to pressure release.
Factors contributing to physical weathering include temperature changes, ice expansion, wind, water, plant roots, and even human activities like construction.
Physical weathering differs from chemical weathering, which involves the alteration of rock composition due to chemical reactions. Chemical weathering usually requires the presence of water and specific minerals susceptible to chemical changes.