Soil Review

Madison Weaver, 4

The Basics of Soil

- Soil makes up the upper most layer of the earth's crust.

- It is composed of both organic and inorganic materials.

- Soil is a mix of oxygen, silicon, aluminum, and iron.

- Minerals present: calcium, magnesium, potassium, sodium, phosphorus.

Soil & Forensic Science

- Scientists examine soil by its "soil horizons" (they deal with the uppermost layer - Horizon O)

- They examine what makes up the soil and how it is unique to its location.

- Soil is valuable physical evidence.

- Soil found at the bottom of shoes can link back to the perp and can be used to justify an alibi.

How is Soil Examined?

- Soil is differentiated by its appearance (color, texture, moisture, etc.)

- There are said to be 1100 different soil colors.

- Samples of soil must be examined when the soil is dry.

- Scientists use microscopes to closely exmaine the soil, looking at the particle shape and size (They also use reflected light).

- It is also examined through density gradiant tubes.

- For a soil to be a match, they must match on EVERY test.

- If the soil has rare minerals or rocks, it is easier to match the soils.

How is Soil Collected?

- Soil is collected by vacuum or tape to lift the particles.

- Scientists need only a little (tablespoon or two) of soil in order to test it.