Unit 7 Assessment

Bobby observed that a metal trash can was covered with rust.  What type of weathering caused the rust on the trash can?

• Mechanical weathering 
• Wind weathering
• Chemical weathering
• Erosion weathering

What is likely to cause cracks on the sidewalk?

• Repeated freezing and thawing of water
• Tree roots or plant roots growing bigger
• Both and A and B
• Neither A or B 

Which diagram represents mechanical weathering?

• G
• F
• H
• J

Which type of climate would cause the greatest rate of weathering?

• Cold and dry
• Cold and humid (wet)
• Warm and humid (wet)
• Warm and dry

A student hiking in a rock area on a mountain notices that wide, deep cracks have formed in some of the large rocks. Some of the cracks are so large that the rocks have broken apart. Which process most likely caused these rocks to crack and creak? 

• Erosion by wind
• Water freezing and thawing
• Erosion by fast-moving
• Sediments being deposited.

When Joe saw the Rocky Mountains for the first time, he exclaimed, "These mountains are much younger than ours back East!" Which feature supports his conclusion that the Rockies were relatively young mountains?

• Their sedimentary layers are still exposed
• They have rounded tops
• They have sharp peaks
• Weathering has not yet hardened the rock

What is the weathering process in which rocks are broken down into smaller pieces (sediments) and do not change the rock composition?

• Acid weathering 
• Gravity weathering
• Chemical weathering
• Mechanical weathering

Which of the following is the most important agent of chemical weathering to form this cave?

• Water - It can carry acid and dissolve rock
• Erosion - Moves the rocks from one place to another
• Wind - It displaces rocks
• Exfoliation - New cracks give chemical reactions the chance to operate

Chemical weathering is the other important type of weathering. Chemical weathering may change the size of pieces of rock materials, but definitely changes the composition. So one type of mineral changes into a different mineral. Chemical weathering works through chemical reactions that cause changes in the minerals.
True or false: chemical weathering causes rocks to change into new types of rocks.

• True
• False

Carbon dioxide (CO2) combines with water as raindrops fall through the atmosphere. This makes a weak acid, called carbonic acid. Carbonic acid is a very common in nature, where it works to dissolve rock. Pollutants, such as sulfur and nitrogen from fossil fuel burning, create sulfuric and nitric acid. Sulfuric and nitric acids are the two main components of acid rain, which speeds up chemical weathering.
This statue was probably destroyed by _____.

• Wind
• Humans
• Acid Rain
• Animals