• Soil is composed of various particles which can be separated and identified. Soil particles range from gravel to sand to clay and each particle has its own identifiable characteristics. The investigation of soil particles is part of soil science, which is sometimes called pedology.
• This activity is a small group activity with adult supervision or a teacher demonstration. Have students collect soil from three different areas. The soil should be dry and free of all plant materials. The soil should be crushed between the students fingers into individual soil particles. There are more than three soil types in the valley and Green Pool area.
• The screen sieves should be arranged with the largest screen size on top, proportionately decreasing in screen size to the closed-bottom container. Place one of the soil samples in the uppermost sieve, cover, and lightly shake it using a back-and-forth motion.

1. Carefully remove the particles from each sieve and place on paper.
2. The sieves should contain the following particles.
3. 1st sieve - gravel
4. 2nd sieve - fine gravel
5. 3rd sieve - coarse sand
6. 4th sieve - fine sand
7. Bottom pan - silt and clay

1. Which soil of the three you investigated has the most gravel? The most sand? The most silt and clay?
2. How does this difference occur?

Take the soils back to school or to area at Miller Springs where balances are located.

Weigh each sample of soil from one of the soil types (brown soil) and record weight from each sieve.

Add the weights of all sieve samples to get total weight of the soil sample.

Determine the percent of gravel, fine gravel, coarse sand, fine sand and silt/clay.

EXAMPLE - Weight of 1st sieve/total weight of soil sample x 100 = % gravel

Repeat this for each soil sample for comparison purposes.

This could lead to such questions as: Which soil will water pass through the quickest or which soil will hold the most water. Students could be encouraged to design an experiment to answer the questions.