By Al Mussen
Background:
The ability of a rock or earth material to transmit a fluid is known as permeability. The ease or difficulty with which the fluid will pass through is dependent upon the type of material. The size and spacing of particles in the material will directly effect the ease at which a fluid can pass through.
Objective:
Demonstrate the apparent difference of the permeability of various earth materials.
Materials:
- buckets of silt (loess)
- sand
- gravel
- clay
- four 2-liter pop bottles
- timer
- ring stands
- beakers
Procedure:
- Cut off bottoms of bottles, drill hole in top cap and put a disc of screening in cap (this can be done ahead of time for the students).
- Label and fill each bottle with a different type of earth material. Place the bottle in the ring stand as shown by instructor.
- Predict what may happen in each bottle when the water is poured onto the dry material. Record your results in the data table below.
- Add water to the bottles. Start timer and measure the time for water to pass through each material. Record this information in your data table.
- Allow the water to drain from the bottle. Repeat the process with the damp material. Record the time for the damp material in the data table below.
- Note any changes in the waters behavior between the dry and wet trials. Record your observations in the data table.
| Type of Material | Prediction of flow | Time of flow-dry | Time of flow-wet | Changes wet vs. dry |
Conclusion:
- Water passes through ______________ in the least amount of time and passes through _______________ in the greatest amount of time.
- Did the water not pass through any of the bottles? Explain.
- Defend the suitability of establishing a landfill or waste storage facility in/on each column of earth materials.