Identify each event as the result of mechanical weathering or chemical weathering. mechanical weathering chemical weathering The minerals in a marble statue react with water to form acids and pores in the structure A piece of rock crumbles after being constantly thrashed by strong waves. Industrial runoff forms cracks in a rocky structure in its path. The rocks in a region are streaked orange after being exposed to repeated rains.
The Correct Answer and Explanation is:
Answers:
- The minerals in a marble statue react with water to form acids and pores in the structure — Chemical weathering
- A piece of rock crumbles after being constantly thrashed by strong waves — Mechanical weathering
- Industrial runoff forms cracks in a rocky structure in its path — Chemical weathering
- The rocks in a region are streaked orange after being exposed to repeated rains — Chemical weathering
Explanation:
Weathering is the process that breaks down rocks and minerals on Earth’s surface. It occurs through two main types: mechanical weathering and chemical weathering. Understanding the difference between these processes helps us interpret how natural and human forces shape the landscape over time.
Mechanical weathering is the physical breakdown of rocks into smaller pieces without changing their chemical composition. One example is when a rock is continuously pounded by waves, causing it to break into fragments. This is a physical force acting on the rock, so it is considered mechanical weathering.
Chemical weathering involves changes in the mineral composition of rocks due to chemical reactions. This type of weathering often occurs when water, oxygen, carbon dioxide, or other chemicals interact with the minerals in rocks. For instance, when the minerals in a marble statue react with water and acids, it leads to the formation of pores and gradual weakening of the material. This is a chemical reaction, not a physical breakdown, making it chemical weathering.
Another example is industrial runoff, which can contain pollutants that chemically react with rocks and cause cracking. The interaction alters the rock’s chemistry, so this is chemical weathering. Similarly, when rocks develop orange streaks after repeated rainfall, it is often due to oxidation. Iron-rich minerals in the rocks react with oxygen and water, forming iron oxides such as rust. This change in chemical composition classifies the process as chemical weathering.
In summary, mechanical weathering involves physical forces, while chemical weathering changes the chemical structure of rocks through reactions.
