Grade Level/Subject
High School Earth Space
Unit
Energy Flow - Groundwater
Enduring
Understanding
The processes of Earth are cyclical in nature,
continually reshaping the Earth and its material with
no loss or gain of matter.
SOL Objectives
ES 2 – Scientific reasoning and logic
ES 8c – Groundwater zones
Title
Porosity and Permeability
Lesson Objective


Inquiry Level
Materials Required
To measure the porosity and permeability of
several particle sizes
To identify the significance of each sediment
property.
2








Safety goggles
2 400-mL beakers
Coarse sand, medium sand, fine sand, and a
mixture of all three
Filter paper
Scissors
2 100-mL clear graduated cylinders
Water
stopwatch
Porosity and Permeability
Background:
The pore space, or porosity, of a rock or sediment is the percent of a material’s
volume that is open space. The permeability is the rate at which water or other fluids
will pass through these open spaces.
Materials:








Safety goggles
2 400-mL beakers
Coarse sand, medium sand, fine sand, and a mixture of all three
Filter paper
Scissors
2 100-mL clear graduated cylinders
Water
stopwatch
Hypothesis:
1. Which sample do you believe has the greatest porosity?
2. Which sample do you believe will take the quickest time to reach the bottom
of the graduated cylinder?
3. Create a hypothesis that addresses the two questions from above.
Procedures:
1. Put on your safety goggles. Use one of the beakers to obtain a portion of one
of the four sand samples assigned to you by your teacher
2. Fold a piece of filter paper in half and then fold it in half again so that it forms a
cone. With scissors, cut off the pointed end and open the paper so that it forms
a funnel. Use it to fill one of the graduated cylinders to the 50-mL level with
sand. Gently tap the cylinder to settle the particles.
3. Fill the other graduated cylinder to the 50-mL level with water.
4. Pour the 50 mL of water carefully, but quickly, into the cylinder containing 50
mL of sand. Your partner will measure the time needed for the water to reach
the bottom of the cylinder. The time recorded should be form the instant the
water is poured into the cylinder to the instant the first drop of water reaches
the bottom of the cylinder. This time indicates the permeability of the sample.
Record the time in the data table.
5. When the water has completely wet all the particles, gently tap the cylinder to
remove air bubbles left between particles.
6. Read and record the water level in the cylinder to the nearest tenth of a
milliliter. When you added water to the sediment, any pore space in the
sediment was replaced by water. The water level is the volume of the water
plus the sediment alone.
7. Subtract the volume of water plus sediment from the original volume of dry
sediment and water (100 mL). This yields the volume of the pore spaces.
Record this volume in the data table. The porosity of the sample is the volume
of pore space divided by the volume of the dry sediment (50mL), multiplied
by 100. Record the porosity in the data table.
8. Place the used, wet sample in the container supplied by your teacher for
particles of that size. Do not pour particles into the sink. Wash out the
graduated cylinder. Wrap a piece of paper towel around a test tube brush and
dry the inside of the cylinder completely.
9. Complete steps 2-8 again for the different sized particles.
Data Table:
Porosity and Permeability Data Table
Coarse Sand
Medium
Fine Sand
Sand
Time for water to reach
cylinder bottom (sec)
Volume of water plus
sediment (mL)
Volume of pore space =
100 mL – (volume of water
plus sediment)
Porosity = volume of pore
space x 100mL / 50 mL
Mixed
Sizes
Analysis:
1. The graduated cylinder in Steps 3 and 4 held 50 mL of sediment and 50 mL of
water. Why wasn’t the final volume of water and sediment 100 mL? Where did
the water go?
2. For which sample was the water level in the graduated cylinder (volume of
water plus sediment) the highest? Why?
3. How is the difference between the final volume and the initial 100-mL volume
related to the porosity of each sample?
4. Which sand size (coarse, medium, or fine) has the greatest permeability?
What is the evidence for your answer?
5. Why does the sample containing a mixture of sand sizes have the poorest
permeability?
6. Which should be more permeable, sandstone or siltstone?