Glass Unit-Forensics 1

What is a mineral?

A solid inorganic substance of natural occurrence.

What is soil?

Naturally deposited materials that cover the Earth's surface and can support plant growth.

What is forensic geology?

The legal application of earth and soil.

What is topsoil?

The outermost layer of soil that supports plant growth.

What is subsoil?

The second layer of soil, immediately under the surface.

What is a fossil?

Preserved remains of plants or animals.

What is sand?

Natural particles with a grain diameter of 1/16mm to 2mm.

Approximately what percentage of the Earth's surface is suitable for agriculture?

10%.

What physical characteristics can be observed in the forensic analysis of soil?

Density, magnetism, particle size, mineralogy.

What chemical tests can be done in the forensic analysis of soil?

Pit tests, trace elements.

What is the organic part of soil called?

Humus, made of microorganisms and decaying dead animals/plants.

What is the probative value of soil? Is it class or individual evidence?

Soil is class evidence, but unique features allow for narrowing down samples.

How is sand classified?

By its parent rock.

What are the main types of sand found on Earth?

Continental, ocean floor, carbonate, tufa.

What is continental sand?

Sand from weathered continental rock.

What is ocean floor sand?

Sand from volcanic materials.

What is carbonate sand?

Sand from fragments of shells.

What is tufa sand?

Sand from ions in salt lakes.

What physical characteristics are used in the forensic analysis of sand?

Shape, color, grain size, sorting.

What does a reaction to acetic acid in a sand sample indicate?

It contains carbonates.

What is an amorphous solid?

A solid that does not crystallize; has a random arrangement of particles.

What is a radial fracture?

Fractures that radiate out from the center of glass after impact.

What is a concentric fracture?

Fractures that form on the same side as the force applied.

What is density?

The ratio of mass to volume.

What is the refractive index?

The measure of the bending of light from one medium to another.

What is the Becke line?

A bright halo that appears around an object when in a liquid with different refractive index.

What are the five types of glass?

Soda-lime, soda-lead, borosilicate, silica, tempered.

How is tempered glass made?

By rapid heating and cooling.

What is laminated glass?

Glass that is layered with plastic.

What is the 3R rule?

Radial fractures form right angles on the reverse side of the force.

How can you determine the order of glass fractures?

Fracture lines stop at existing fracture lines.

Which holes are larger, entry or exit holes?

Exit holes are larger.

Is glass class or individual evidence?

Glass is class evidence, but can be individualized if broken pieces fit together.