Weathering and Erosion - Learning Services Home

Name Date Class
2
Laboratory
Activity
Erosion and Soil Permeability
The permeability of soil, which describes how water can flow through the soil, can be a
contributing factor in erosion. Soil that is very porous can have high permeability. However, if a
soil’s pores are not connected, permeability can still be low. In order for water to flow easily, the
pores in soil must be connected. The porosity of different soils is one factor that determines how
erosion will affect them.
Strategy
You will compare the permeability of three different soil types by conducting “perc” tests.
You will see how soils with different permeabilities are eroded by water.
Hands-On Activities
Copyright © Glencoe/McGraw-Hill, a division of the McGraw-Hill Companies, Inc.
Materials
small coffee cans with both ends removed (3)
permanent marker
metric ruler
plastic tubs, about 30 cm ✕ 30 cm ✕ 30 cm (3)
hand shovel
sandy soil, approximately 2.5 kg
loamy soil, approximately 2.5 kg
clay soil, approximately 2.5 kg
500-mL beaker
water
stopwatch
*watch with second hand
10-cm wooden block
sprinkler can
*Alternate materials
WARNING: Be sure to wash your hands after touching the materials used in this lab.
Procedure
Part A—Determining Porosity
1. Use the marker to make a line 3 cm from
one end of each coffee can. Label the tubs
Sandy, Loamy, and Clay to designate the
soil types you will be testing.
2. Fill each of the plastic tubs with the type of
soil that corresponds to the label. Use the
shovel to pack down the soil.
3. For each soil type, observe the color and
texture of the soil and presence of any
organisms in the soil. Record your observations
in Table 1 in the Data and Observations
section.
4. Predict the permeability of each soil as low,
medium, or high. Record your predictions
in Table 1.
5. Press a coffee can into the sandy soil up to
the mark at the 3-cm line. Press a coffee
can into each of the two other soils.
6. Perform a “perc” test on the sandy soil by
pouring water in the cans. Have your stopwatch
ready to begin timing when the
water first reaches the soil. Slowly pour 500
mL of water from the beaker into the can
in the sandy soil. Stop timing when all the
water has sunk into the soil. In Table 1,
record the amount of time it took for all
the water to sink below the soil surface.
7. Repeat steps 5 and 6 for the other two soils.
Try to keep your rate and style of pouring
the water the same in each perc test.
Weathering and Erosion 13