Name _______________________________________________
Date ______________
Lab # _______________
Virtual Lab – Porosity and Permeability
Purpose: To investigate how different types of soil hold water.
Question: How does soil type affect the movement of groundwater?
Background Information:
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. Groundwater moves through the spaces
between soil particles. These spaces are called pores.
Not all soils have the same amount of pore space.
The amount of pore space, or porosity depends on the
number and size of pores in soil. If 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.
Explain porosity and permeability in your own
words.
Porosity –
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 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.
Pre-Lab :
Describe the difference between a well sorted sediment sample and a poorly sorted sediment sample.
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Part 1
Procedure:
1. Color in the pore spaces between the particles blue to see which has the highest porosity.
2. Label the diagrams below either Sorted or Unsorted
1. Which has the most open space?
Sorted or Unsorted sediments?
Circle one
2. Which would hold the most water? _______________ Why? ________________________________
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3. What is the relationship between sorting and porosity? ______________________________________
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4. What would this look like on a graph?
Porosity
Pore size
Part 2: Get a chrome book and log on.
1. Go to http://hmxearthscience.com/Warehouse/geology/surface_processes/animations/perm.poros.swf
Before you release the water, answer the questions below.
2. Which tube do you think will flow the fastest? ____________________ Explain why ______________
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3. Which tube do you think will flow the slowest? ____________________ Explain why ____________
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
Release the water and watch, repeat to see which tube is the fastest / slowest.
4. Where your predictions correct? ______________________ Why or why not? ________________
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5. Complete the column below
Table 1
Column
A
B
C
D
Bead Size and color Infiltration time
(seconds)
4mm
Red
8 mm
yellow
12 mm
Green
Mixed
Are these particles
Sorted or unsorted?
Pore size
S,M, L
3
2
1
4
6. Compare the amount of water stored in the three sorted samples to the amount of water in the unsorted
sample. ____________________________________________________________________________
7. What is the relationship between bead/sediment size relate to Infiltration time? ____________________
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8. What would this look like on a graph?
Infiltration time
9.
Sediment/bead size
Describe the difference between the infiltration rate of a well sorted sediment sample and an unsorted
sorted sediment sample.
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Part 2
1. Go to http://regentsearth.com/ILLUSTRATED%20GLOSSARY/Infiltration.htm
2. Before you release the water, use page 6 & 7 of the ESRT to fill in the grain size on the table below and
answer questions 3 and 4.
3. Predict which column will empty the slowest_________________________ why? _______________
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4. Predict which column will empty the fastest_________________________ why? _______________
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Table 2
Sediment Name
Grain Size
Gravel
5-10 mm
Rate of permeability of 1 meter of water
Sand
Silt
Clay
5. Where your predictions correct? ______________________ Why or why not? ________________
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6. What is the relationship between the grain size and rate of permeability of water? ________________
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7. What would this look like on a graph? Be sure to label axis.
Permeability
Rate
Grain Size
8. Based on this investigation, which type of soil is the most permeable? Which is the least permeable? How
do you know? Support your statement with evidence. _________________________________
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