Water and the Earth 2

Your teacher shows you pictures of an old cemetery. The writing on the gravestones has become so worn that you cannot read it. The teacher explains that acids present in the rain caused the surface of the gravestones to dissolve, then the water carried the dissolved material away into the soil. What kind of weathering occurred?

• Mechanical
• Chemical and mechanical
• Neither chemical nor mechanical
• Chemical

You go on a field trip and observe some unusual rock formations. The tour guide explains that the rock formations are the result of thousands of years of winds gradually breaking apart some of the rock. What kind of weathering is this?

• Chemical and mechanical
• Neither chemical nor mechanical
• Mechanical
• Chemical

Which of these is a chemical change that can break down rock material?

• Acids can dissolve the minerals in rock.
• Moving water can erode and weather rock.
• Heat can melt rock into different forms.
• Plant roots can tear rocks apart.

Over time, the surface of rock changes from rough to smooth. A geologist notes that the water flowing over the rock is slightly acidic and concludes that chemical weathering caused the change. Is the geologist correct?

• Yes, because chemical weathering is caused by water dissolving or changing the minerals in rock.
• No, because chemical weathering is caused when water freezes in cracks in rock.
• No, because chemical weathering is usually caused by water that is not acidic.
• Yes, because chemical weathering is caused by acid water breaking off pieces of rock.

Water seeps inside cracks in a boulder and freezes. Over time, the crack expands and the boulder cracks in half. What process caused this change in the rock?

• chemical weathering
• physical sublimation
• land erosion
• mechanical weathering

How do animals contribute to mechanical weathering?

• They dissolve rocks when they decompose.
• They crush rocks when they walk over them.
• They release carbon dioxide which chemically changes rock.
• Their remains fossilize into new layers of sedimentary rocks.

Which best describes the process of mechanical weathering?

• rocks are broken apart
• acid rain falls to the ground
• carbon dioxide combines with water
• the freezing of solid matter

Chemical weathering occurs when minerals in rocks are changed chemically. Which of these will most likely change the rate of chemical weathering on a rock?

• decrease in air temperature
• increase in rainfall amounts
• slow movement of a glacier
• rapid growth of plant roots

There are many natural rock formations such as the one shown. Which two processes most likely removed the center portion of the rock and transported it to another location?

• earthquakes and wind

• tectonic activity and magma

• chemical weathering and glaciers

• mechanical weathering and water

What is happening when rocks are broken down by both physical and chemical changes?

• weathering
• deposition
• condensation
• decomposing