Laboratory Manual for Introductory Geology 4e

EXERCISE 14.1
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Course:
Factors Affecting Infiltration and Groundwater Flow (continued)
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(c) Which materials transmitted the most water? Which retained the most water?
(d) What properties of the materials are correlated with good water transmission? Which are correlated with flow
retardation and water retention?
material a good aquifer. Pumice and scoria (both vesicular igneous rocks) are very
porous, but their pores are not connected. Pore spaces must be connected for water
to move from one to another—a property called permeability. Materials that do not
transmit water are called aquitards because they retard water, or aquicludes because
they exclude water from passing through.
The materials in Exercise 14.1 that transmitted water easily had to be both porous
and permeable. Exercise 14.2 explores these properties.
EXERCISE 14.2
The Difference between Porosity and Permeability
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Course:
Section:
Date:
Are all porous rocks aquifers? Hold pieces of highly porous pumice and scoria above two beakers, or rest them on the rims
as shown in the following figure. Using a water dropper, slowly add water to the top of each rock and carefully observe how
much water passes into the beaker.
Porosity and permeability in pumice and scoria.
(continued )
14.2 AQUIFERS AND AQUITARDS
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