Objective: Learn the manipulative skills that are involved in the analyzing of soils. Analyze the results by comparing different soils.

There are two important parts of soil analysis: dispersion and sedimentation. The soils will be chemically dispersed by the use of sodium hexametaphosphate and mechanically dispersed by the use of a milkshake maker and plunger. Analysis will be accomplished by the use of the Bouyoucous hydrometer.

Materials:

50 grams of soil to analyze
5ml of (5%) sodium hexametaphosphate or Sodium pyrophosphate.
Electrical stirrers
Distilled water squirt bottle
1 liter graduated cylinder
Bouyoucous hydrometer
Watch or clock with second hand
Plunger

Make a presentation table:

Methods:

1. Accurately weigh out 50 grams of very dry soil. (S)

2. Transfer the soil into the baffled stirring cup. Fill the cup half full with distilled water.

3. Add 5ml of dispersing agent (sodium hexametaphosphate)

4. Stir for 4 to 10 minutes. (shorter for sandy, longer for clayey)

5. Pour the soil mixture into the 1 liter graduated cylinder, using a squirt bottle to make sure all of the soil gets into the cylinder.

6. Fill the graduated cylinder up to the 1 liter mark with distilled water.

7. Use the plunger and move it up and down rather vigorously to disperse all of the particles. This takes 1 to 4 minutes.

8. Pull out the plunger and take note of time.

9. Very gently insert the hydrometer in the suspension and read the hydrometer at 40 seconds from the removal of the plunger. Record the hydrometer reading. (R1)

10. Remove the hydrometer from the cylinder and leave the cylinder for two hours.

11. After two hours have elapsed, very gradually insert the hydrometer in the suspension and record the hydrometer reading. (R2)