Soil Formation

Question

Five soil forming factors:
1. Parent material
2. Climate
3. Topography
4. Biological factors
5. Time
Question 1
"Where do the minerals come from?" Sanjay asked. "Usually from parent material," his teacher replied. Ms.Winston suggested they set up an experiment to demonstrate where minerals and other soil particles come from. This is their setup.
In this experiment, the brown sugar represents the parent material. What role does water play in soil formation? One choice is NOT correct.
Responses
A The dripping water is mechanically weatherng the parent rock causing pieces to move down the incline.The dripping water is mechanically weatherng the parent rock causing pieces to move down the incline.
B The flowing water causes the parent rock particles to be eroded down hill and collect at the bottom of the tray.The flowing water causes the parent rock particles to be eroded down hill and collect at the bottom of the tray.
C The incline speeds up the erosion of sugar particles, the minerals and soil components, away from the parent material.The incline speeds up the erosion of sugar particles, the minerals and soil components, away from the parent material.
D The dripping water is an is chemically weathering the parent rock causing individual particles to break away from the original mound.The dripping water is an is chemically weathering the parent rock causing individual particles to break away from the original mound.
Question 2
"Let's think about climate differences and our list of soil forming conditions," said Ms. Winston. She told the students to imagine a similar situation taking place in two biomes: a temperate deciduous forest and a tropical rainforest. Using the initial experiment, what differences would you expect based on our list of five conditions of soil formation?
Responses
A There would be little difference in soil formation since both biomes are forests.There would be little difference in soil formation since both biomes are forests.
B There would be more biological activity in the temperature deciduous forest so the parent rock would be broken down faster.There would be more biological activity in the temperature deciduous forest so the parent rock would be broken down faster.
C The increased precipitation in the tropical rainforest would weather parent material at a faster rate but it would also erode faster.The increased precipitation in the tropical rainforest would weather parent material at a faster rate but it would also erode faster.
D The increased temperatures and the increased rain frequency would cause the parent rock to weather more quickly in the tropical rainforest.The increased temperatures and the increased rain frequency would cause the parent rock to weather more quickly in the tropical rainforest.

Answer 1

Question 1: What role does water play in soil formation? One choice is NOT correct.

The correct answer is D. "The dripping water is chemically weathering the parent rock causing individual particles to break away from the original mound."

While water can partake in chemical weathering, the way it is stated in the context of the experiment appears to describe a more mechanical process that is happening due to movement and erosion, rather than a chemical alteration at this stage. Mechanical weathering refers primarily to the physical breakdown of material, whereas chemical weathering involves changes to the minerals.

Question 2: Using the initial experiment, what differences would you expect based on our list of five conditions of soil formation?

The correct answer is C. "The increased precipitation in the tropical rainforest would weather parent material at a faster rate but it would also erode faster."

This statement accurately reflects the impact of climate on soil formation. In a tropical rainforest, the high levels of rainfall lead to faster weathering of parent material due to both physical and chemical processes, and also cause increased erosion due to water runoff, compared to the temperate deciduous forest.