# AP Environmental Science : Soil and Geology

## Example Questions

### Example Question #1 : Geological Time Scale

Geological time scales are used to measure spans of time. In terms of geological time scales, which category represents the smallest length of time?

Eon

Period

Era

Supereon

Period

Explanation:

The correct response is period. This would be the smallest measurement of time given the answer choices.

The order from longest to shortest is shown here: Supereon > Eon > Era > Period

### Example Question #1 : Soil And Geology

Geological time scales are used to measure spans of time. In terms of geological time scales, which category represents the longest length of time?

Era

Period

Age

Epoch

Era

Explanation:

The correct response is era because it represents longer periods of time on the geological time scale. The answer choicest from longest to shortest are as follows: Era > Period > Epoch > Age.

### Example Question #2 : Soil And Geology

Examine the given block diagram. Each letter represents a depositional event or a period of erosion. Place the letters in order from the oldest to youngest event.

E, C, B, A, D, F

F, D, E, A, B, C

E, F, D, A, B, C

C, B, A, D, F, E

C, B, A, E, D, F

C, B, A, E, D, F

Explanation:

The law of superposition states that the oldest rock layers are at the bottom. A real world example of this often takes place while cooking. When making a seven-layer dip, for instance, you place the oldest layer on the bottom of the dish and stack layers on top. The layer on top is the youngest. The earth is made of rock layers deposited in a similar way.

E represents a period of erosion, meaning there is "missing time" (rock layers have been eroded, so there are no rocks representing that time).

### Example Question #3 : Soil And Geology

Which of the following rock types is a result of the rapid cooling of magma?

Oceanic

Igneous

Metamorphic

Fossilized

Sedimentary

Igneous

Explanation:

The three main rock types are sedimentary, igneous, and metamorphic. Sedimentary rock is the result of the build up of sediment, such as sand or dirt. Igneous rocks are the result of the cooling of lava and molten rock, and can be crystalline in structure. Metamorphic rock is the compression of igneous and/or sedimentary rock, creating a new type of rock from intense pressure. Metamorphic rock comprises the majority of the Earth's crust.

### Example Question #5 : Soil And Geology

A scientist is examining two pebbles of a similar composition lying next to each other in a stream. One has a smooth, polished texture, while the other is angular with sharp edges. The differences in surface texture can indicate which of the following regarding the distance each pebble has traveled?

The round pebble has traveled a farther distance and the angular pebble has traveled a short distance

Both pebbles are from far away but come from different parent rocks

The angular pebble has traveled a farther distance and the round pebble has traveled a short distance.

None of these

The round pebble has traveled a farther distance and the angular pebble has traveled a short distance

Explanation:

As rocks travel further from the original outcrop, bumps and abrasions round corners and polish the rock.

### Example Question #6 : Soil And Geology

Which of the following factors can cause a sedimentary rock to change into a metamorphic rock?

Increasing temperature

All of these

Increasing pressure

All of these

Explanation:

Increasing temperature and pressure—through burial or submersion—causes the minerals that compose the rock to become unstable. This results in recrystallization of the minerals, which forms a new rock.

### Example Question #1 : Rock Cycle

A sedimentary rock is buried deep within the earth. At a certain depth, the rock melts completely and recrystallizes. Which of the following best identifies what type of rock is formed post recrystallization?

Conglomerate

Sedimentary

Igneous

Metamorphic

Igneous

Explanation:

The question indicated that the rock melted completely. When a partially melted rock recrystallizes, it becomes a metamorphic rock; however, when a rock completely melts and any crystallization occurs, it results in the production of an igneous rock.

### Example Question #4 : Soil And Geology

Which of the following best explains the difference between weathering and erosion?

Weathering is the physical process that creates sediment, while erosion is the chemical process of creating sediment

Weathering is the process that creates sediment, while erosion is the process of transporting sediment

Weathering is the chemical process that creates sediment, while erosion is the physical process of creating sediment

Erosion is the process that creates sediment, while weathering is the process of transporting sediment

Weathering is the process that creates sediment, while erosion is the process of transporting sediment

Explanation:

Weathering is a process that creates sediment. There are physical and chemical weathering processes. On the other hand, erosion is described as a process that transports sediment. Erosion transports sediment through exogenous processes, such as by water or wind.

### Example Question #5 : Soil And Geology

In the desert, a rock can experience seasonal cycles of freezing and cooling. The heat of the day causes ice to melt and the cold temperatures at night causes water to freeze and expand inside cracks present in the rock. This example is indicative of which of the following types of weathering?

Physical weathering

Seasonal weathering

Chemical weathering

Exergonic weathering

Physical weathering

Explanation:

The freeze-thaw cycle acts like a chisel that produces fractures throughout the rock. Water rests in cracks on the rock’s surface and when it freezes it expands and causes more fractures. Water can then lay in these new fractures and further weather or crack the rock. This example represents a physical weathering process.

### Example Question #6 : Soil And Geology

Which of the following statements about the rock cycle is not true?

Igneous rock can form from either sedimentary or metamorphic rock.

Sedimentary rock can become metamorphic rock, but not igneous rock.

Sedimentary rock can become metamorphic rock or igneous rock.

Metamorphic rock can become sedimentary rock or igneous rock.