Name:_________________________________Class:____________________ Date:_____________
Earth Science- Ms. Gill
Water Cycle & Ground Water
Water Movement in the ground Lab
Directions:
Complete the procedure and collect all data. Use the theoretical data to complete the three graphs. Type the
definitions of all vocabulary words and type all questions. Due:_________________________
Introduction:
Ground water is water stored under the surface of the Earth. Convey to the students that ground
water sometimes takes hundreds of years to accumulate. A good example of this occurs in the Sahara Desert
in Africa, where ground water has accumulated for thousands of years and is still being used for drinking and
irrigation. Ground water is stored in the ground below us, where different types of rocks can act as
reservoirs. Sand or sandstone is the best material for a reservoir and forms extensive aquifers underground,
but not all sands are created equal, as students will find out in lab.
Filtering water through different porous substances cleans water naturally in the ground. Substances like
charcoal and diatomite (white powder that people put in pools), help to filter small particles that may be
suspended in water.
The ground, on which we live, is made up of many layers of different types of rocks. Water can move
into the tiny pores within the rocks or soil. As they move, the different rocks can trap the particles in the
pores. Some rocks have more pores than other rocks and can act as a reservoir of water or an aquifer. Some
municipal water supplies depend on ground water for a source of drinking water. Filtering techniques are used
in municipal water supplies. Water from a reservoir is cleaned through a combination of filtering and chemical
processes.
Vocabulary
Pore space
Permeability
Water retained
Impermeable
Infilitration
Runoff
Capillary Action
Ground Water
Sorting
Procedure:
1. Observe the set-up of the three tubes each filled with a different size bead. Examine the beads inside the
tubes. Are the beads dry? Yes or No? Explain why wet beads would affect your results.
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2. Measure the height of the beads in centimeters from the base of the tube to the top of the highest bead.
Record this data on the attached results page. Do NOT attempt to level the beads by shaking, this will pack
the sediments and affect the results. Explain what packing the particles will do to the results:
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3. Ensure that the clamp is securely clipped on the bottom of the tube. Call your teacher over if you are not
sure.
4. Using a graduated cylinder measure 200mL. In order to time the “wetting front” pour about 20 mL of the
water in the cylinder into your first column. Start the stop watch as soon as the water hits the beads and
stop the stop watch when the water has reached the bottom of the column.
5. Enter that time on Row 1 of the Report Sheet. This time indicates the permeability of the material.
6. Continue to slowly pour water into the column until the water is just up to the top of the particles. (Allow
time for the water to run down the sides after each addition so you can find the true level.)
7. On Row 3 of the report sheet record the total amount of water it took to just cover the beads. (200mL –
the amount left in the graduated cylinder.)
8. To determine the amount of water retained by the particles, drain the water into a dry beaker by opening
the hose clamp. Measure this in a graduated cylinder and enter in Row 5 of the Report Sheet.
9. Repeat these procedures twice using different sized particles. Ensure that you have data for rows 1, 3 & 5
for each column before continuing.
10. After you have taken all measurements, do all the necessary calculations to fill in row 2, 4, & 6 on the lab
report sheet.
A) Row 2: Find the rate of flow by dividing as follows:
Height of beads in centimeters
Rate of Flow=
Seconds from row 1
B) Row 4: Calculate the percent of pore space (porosity) by using the following formula:
% Porosity=
Volume of Pore Space [ Row 3]
% Porosity=
x 100
Total volume of particle [300 mL]
C) Row 6: Calculate the water retained by subtracting:
Water retained = Water required to fill pores [Row 3] –
Water recoverd [row 6]
Data Tables
Trial #1: Particle Size: 4mm, Volume of beads: 300mL , Height of beads (cm): _______________
Row
Measurement
Experiment
Theory
1
Wetting Front Travel Time ( sec)
3.6
2
Rate of Flow ( cm/sec)
8.3
3
Water required to fill pores (mL)
120
4
Percent Pore Space
40
5
Water Recovered (mL)
106
6
Water Retained (mL
14
Trial #2: Particle Size: 7mm, Volume of beads: 300mL , Height of beads (cm): _______________
Row
Measurement
Experiment
Theory
1
Wetting Front Travel Time ( sec)
3.0
2
Rate of Flow ( cm/sec)
10
3
Water required to fill pores (mL)
120
4
Percent Pore Space
40
5
Water Recovered (mL)
112
6
Water Retained (mL
8
Trial #3: Particle Size: 12mm, Volume of beads: 300mL , Height of beads (cm): _______________
Row
Measurement
Experiment
Theory
1
Wetting Front Travel Time ( sec)
1.5
2
Rate of Flow ( cm/sec)
20
3
Water required to fill pores (mL)
120
4
Percent Pore Space
40
5
Water Recovered (mL)
116
6
Water Retained (mL
4
Permeability (cm/sec)
Graphing: Complete the following graphs by giving each a title and a scale. Plot three points on each graph to
represent your data for each column. Describe the relationship fully in the box provided.
Describe fully the relationship:
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Particle size (mm)
% Pore Space
Describe fully the relationship:
______________________________
______________________________
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Water Retained (mL)
Particle size (mm)
Describe fully the relationship:
______________________________
______________________________
______________________________
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Particle size (mm)
Discussion Questions:
1) What is the effect of increasing particle size on percent of the following?
a. pore space?_____________________________________________________________________
b. water retained?__________________________________________________________________
c. time necessary for infiltration?_______________________________________________________
d. rate of infiltration?_______________________________________________________________
2) If an area has very small sized particles in the upper soil, what is the effect on each of the following?
a. runoff?________________________________________________________________________
b. time of infilitration?______________________________________________________________
c. rate of infiltration?_______________________________________________________________
3) Compared to the tube of large particle size, mixing the particle sizes in the tube will have what effect on…
a) the percentage of pore space? ________________________________________________________
b) the permeability? ________________________________________________________________
c) the amount of water retained? ______________________________________________________
4) Which particle size will have the greatest capillarity? ___________________________________
5) To which layer underground can water infiltrate? ______________________________________
6) Identify a source of experimental error that would adversely affect your results.
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7) Use evidence of your data compared to the theoretical data to explain the effect of that error on your
data.______________________________________________________________________________
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Conclusion: What factors control the amount of water that flows through the soil?
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