Chapter 5: Weathering, Soil and Mass Wasting
Name__________________________________
Part I: How does soil type affect the movement of ground water?
Groundwater is water that moves through soil and rocks below Earth's surface.
When groundwater moves through soil, the structure of the soil affects its movement. The three particles that
determine soil structure are sand, silt, and clay. Sand particles can be seen with the naked eye and range in width
from 0.05 to 2.00 mm. A microscope must be used to see silt particles, which are between 0.002 and 0.05 mm in
width. An electron microscope is required to see clay particles, which are less than 0.002 mm wide.
Soil type depends on how much of each kind of particle makes up the soil. There are 13 types of soil.
Groundwater moves through the spaces between soil particles. These spaces are called pores. Not all soils have the
same amount of pore space. Porosity depends on the number and size of pores in soil. You can find the volume of
pore space in a soil by determining the volume of water its pores are capable of holding. The volume of pore space
divided by the volume of a soil sample determines its porosity. This measurement is given as a percentage of the
volume of the soil.
The pores in soil are all connected, allowing water to pass through them. This means that soil is permeable. The ease
with which water moves through the soil is called permeability. A soil with high porosity and many small pores can
hold a lot of water, but it takes longer for the water to enter all the pores. This means that when a soil has higher
porosity it has lower permeability. A soil's porosity and permeability are important to many people. Farmers must be
aware of these soil conditions so they can
determine the best way to grow crops. Builders
also consider these conditions in the area they
plan to build. Environmentalists are concerned
with porosity and permeability when there is a risk
that a pollutant might be introduced into the
groundwater supply.
In this Virtual Lab, you will investigate how
different types of soil hold water. You will collect
data and use it to make observations about the relationship of soil porosity to soil permeability. Follow directions on
the website to collect data. http://www.glencoe.com/sites/common_assets/science/virtual_labs/CT02/CT02.html
Objectives:
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Determine the porosity of various types of soil.
Define the relationship between porosity and permeability.
Describe how a soil's porosity and permeability affect the movement of groundwater.
1. Collect data for each soil type and porosity and fill in the table below.
Soil Type
Sand
Loamy Sand
Sandy Loam
Silt
Silt Loam
Loam
Sandy Clay Loam
Sandy Clay
Sand
Porosity %
Clay Loam
Silt Clay
Clay
Heavy Clay
2. Describe what determines the texture of soil?
3. What is meant by the permeability of a soil? What is porosity and how is it related to permeability?
4. Based on your experiment, which type of soil is the most permeable? Which is the least permeable? How do you
know?
5. Explain why surface runoff, or rain not absorbed by the soil, occurs much more often in areas with soils with a high
clay content.
6. Soil type and texture are very important to farmers. Too little water in the soil may cause plants to wilt and die.
Too much water in the soil can disrupt s plant’s ability to take in oxygen. Based on your data, which type of soil do
you think is best for agriculture? Explain your answer.
7. Farmers often have problems with soil erosion when they clear their fields after the growing season. Soil type is
one factor that influences erosion. Some soil types are more prone to the erosion than others. Based on the data you
gathered in this experiment, which soil types do you think are the most easily eroded, soils with a high sand content
or soils with a high clay content? Explain your answer.
Part II: Quizlet Review
1. Go to https://quizlet.com/113656486/chapter-5-weathering-soilmass-wasting-flash-cards/?new and complete the following:
A. Complete the flash cards for this quizlet. Write down 5 terms (and
their definitions) that you had difficulty with and need to study.
B. Play Scatter! What is your time the first go-around? ___________
-Improve your score!! What is your time the second attempt? ____________
C. Set up a test! Make a 30 question test (15 matching and 15 fill in the blank). Complete the test. What was your
score? ____________/ 30