POROSITY AND PERMEABILITY
INVESTIGATION
This investigation covers Skill P and E
SKILL P: Planning
SKILL E: Evaluating evidence and procedures
Make sure that you are familiar with the full details of
these skills and their mark schemes.
Your task is to devise a method of assessing the porosity
and permeability of a variety of rocks, put it into action,
evaluate the data it generates and the methods you used. You
should also discuss the relevance of porosity and permeability
to economic geology. For this, you might consider its impacts
on:
: water supply, springs, and aquifers
: reservoirs and leakage below dams
: oil reservoir rocks within an oil trap
: underground mining – especially coal-and the flow of water
in mines
: waste disposal in quarries and the flow of leachate into
water supplies
: civil engineering: water tables flooding and the stability of
slopes
Pages 72 –73 of Geological Science by McLeish may
provide some useful ideas from which you might formulate
hypothesis. As a starting point, you may wish to consider
hypotheses which relate porosity and/or permeability with
one or more variables, such as grain size and shape, degree
of sorting, pore space, packing, cementation, rock type, etc.
You can choose from the equipment listed below to design
experiments to test hypotheses. Consult NJA for advise/help.
Sieve stacks
Unconsolidated sediments
Containers of different shapes
Plastic measuring cylinders
Balances
Marbles
Polystyrene Spheres
Rock types
Devise a hypothesis that relates to porosity and one or
more variables and / or
Devise a hypothesis that relates permeability to one or
more variables
Design experiments to test your hypotheses. Describe the
geological aims of your hypotheses by relating it to
specific geological issues.
You can choose the same variables for each hypothesis
or entirely different variables that can be tested are –
Grain size, degree of sorting, pore
space/packing/cementation, rock type as groups
igneous/sedimentary/metamorphic or specific rocks, grain
shape
For Skill P:
Develop hypotheses for porosity/permeability and relate
these to a geological situation demonstrating scientific
knowledge and understanding.
Devise and carry out experiments using appropriate
methods/equipment, describe/explain these clearly refering
to number/range of observations/measurements, refer to
safety issues, make predictions where relevant.
Work should be written as a clear account using
specialist terms, with accurate spelling, punctuation,
grammer.
For Skill E:
Show clear evaluation of the methods used in the
experiments carried out:- their suitability, limitations,
sources of error, possible improvements, overall reliability,
and effect on the conclusions related to the original
hypotheses
Set out your work with clear introduction, method,
results, conclusion, evaluation sections .Make sure you
include the evidence for skills P and E above outlined
above.