Earth's Dynamic Surface - Weathering

Which of the following is an example of chemical weathering?

• Ice wedging

• Rusting of iron-rich rocks

• Abrasion by wind

• Root wedging

Answer explanation

Rusting of iron-rich rocks is a chemical weathering process where iron reacts with oxygen and moisture, forming rust. In contrast, ice wedging, abrasion, and root wedging are physical weathering processes.

What is the main difference between weathering and erosion?

• Weathering involves movement, erosion does not

• Erosion breaks rocks down, weathering moves them

• Weathering breaks rocks down, erosion moves them

• Both are the same process

Answer explanation

The main difference is that weathering breaks down rocks into smaller pieces, while erosion involves the movement of those pieces from one location to another. Thus, the correct choice is: Weathering breaks rocks down, erosion moves them.

Which of the following is a method used to prevent soil erosion?

• Deforestation

• Overgrazing

• Planting cover crops

• Removing vegetation

Answer explanation

Planting cover crops helps prevent soil erosion by stabilizing the soil with roots, reducing runoff, and improving soil health. In contrast, deforestation, overgrazing, and removing vegetation all contribute to increased erosion.

Tags

NGSS.MS-LS2-5

Which factor most directly increases the rate of physical (mechanical) weathering?

• High rainfall

• High temperature fluctuations

• Low wind speed

• Low humidity

Answer explanation

High temperature fluctuations cause expansion and contraction of rocks, leading to cracks and breakdown. This process, known as thermal stress, directly increases the rate of physical weathering, making it the most significant factor.

A student observes that limestone statues in a city are becoming smoother and losing detail over time. Which process is most likely responsible for this change?

• Physical weathering by wind

• Chemical weathering by acid rain

• Erosion by glaciers

• Deposition by rivers

Answer explanation

The smoothness and loss of detail in limestone statues are primarily due to chemical weathering by acid rain, which reacts with the calcium carbonate in limestone, causing it to dissolve and erode over time.

Tags

NGSS.MS-ESS2-2

Explain how planting trees on a hillside can help reduce soil erosion.

• The trees absorb sunlight, making the soil drier

• The roots hold the soil in place, preventing it from being washed away

• The leaves block all rainfall from reaching the ground

• The trees increase wind speed, blowing soil away

Answer explanation

The roots of trees anchor the soil, preventing it from being washed away by rain or runoff. This stabilizes the hillside and significantly reduces soil erosion, making it the correct choice.

Tags

NGSS.MS-ESS3-4

Which of the following best describes the impact of erosion on landscapes over long periods?

• Erosion only affects small rocks and has no impact on landscapes

• Erosion can create valleys, canyons, and change the shape of mountains

• Erosion always makes landscapes higher

• Erosion only occurs in deserts

Answer explanation

Erosion significantly shapes landscapes over time, creating features like valleys and canyons, and altering mountain shapes. This highlights the dynamic nature of erosion, making the second choice the best description.

Tags

NGSS.MS-ESS2-2

A river flows through a region with both soft and hard rock layers. Over thousands of years, the river carves a deep canyon. Which statement best explains this process?

• The river deposits more sediment in the hard rock

• The river erodes the soft rock faster than the hard rock, deepening the canyon

• The river only affects the hard rock

• The river has no effect on the landscape

Answer explanation

The river erodes the soft rock faster than the hard rock, which allows it to carve a deeper canyon over time. This differential erosion is key to the canyon's formation.

Tags

NGSS.MS-ESS2-2

A construction company is planning to build a road on a steep slope. As an environmental consultant, what combination of strategies would you recommend to minimize soil erosion during and after construction? Justify your answer.

• Remove all vegetation and leave the soil exposed

• Use retaining walls, plant grass, and install proper drainage systems

• Only use heavy machinery to compact the soil

• Build the road without any additional measures

Answer explanation

Using retaining walls, planting grass, and installing proper drainage systems effectively reduces soil erosion by stabilizing the slope, promoting vegetation growth, and managing water runoff, unlike the other options which would exacerbate erosion.

Tags

NGSS.MS-LS2-5

NGSS.MS-ETS1-3

NGSS.MS-ETS1-4

A science class is investigating the effects of acid rain on different types of rocks. They place samples of limestone and granite in a solution with a low pH. After several days, the limestone shows significant signs of erosion, while the granite remains mostly unchanged. Using your knowledge of chemical weathering, explain why this occurs.

• Limestone is more resistant to acid than granite

• Granite dissolves faster in acid than limestone

• Limestone reacts with acid, causing it to erode more quickly than granite

• Both rocks are equally affected by acid

Answer explanation

Limestone is primarily composed of calcium carbonate, which reacts with acids, leading to its erosion. In contrast, granite, made of silicate minerals, is much less reactive to acid, resulting in minimal changes.

Tags

NGSS.MS-ESS2-2

NGSS.MS-PS1-2