Chapter 14 Glass Evidence

The speed of light passing through air is slightly:

slower than the speed of light passing through a vacuum, because air is slightly denser than a vacuum.

When light travels through any medium other than a vacuum, the particles in that medium slow the light down. As the density of the medium increases, the:

speed of light passing through that material decreases.

If the refractive indexes of several different liquids are known, the:

submersion method can be used to estimate the refractive index of the glass.

Silicon dioxide is:

the chemical name for silica.

If the refractive index of the liquid medium is different than the refractive index of the piece of glass, a halo-like ring appears around the edge of the glass. This halo-like effect is called a:

Becke line.

Snell's law

describes the behavior of light as it travels from one medium into a different medium.

Glass is called an amphibious solid because its atoms are arranged in a random fashion.

false

The primary ingredient of glass is carbon dioxide.

false

When glass is hit:

it can stretch slightly

As a bullet passes through glass, it pushes some glass ahead of it, causing a cone-shaped piece of glass to exit along with the bullet. The cone of glass makes the exit hole:

larger than the entrance hole of the bullet.

Density of glass is calculated by dividing the:

mass of a substance by its volume.

The refractive index is a tool used to study how light bends as it passes through:

one substance and into another

Glass will break first on the weaker side, the side:

opposite the strike. Radial fractures will result.

By examining glass fracture patterns, it is:

possible to determine which side of the glass was hit.

One method of determining if the evidence glass matches the glass from the crime scene is to compare the:

refractive index of the evidence glass to the refractive index of the glass from the crime scene.

The submersion method involves placing the glass fragment into different liquids of known refractive indexes. If a piece of glass and a liquid have the same refractive index, the glass fragment will seem:

to disappear when placed in the liquid.

Each type of glass has a density that is specific to that glass. One method of matching glass fragments is by a density comparison.

true

Fine glassware and decorative art glass, called crystal or leaded glass, contain lead oxide rather than calcium oxide.

true

Glass is a hard, amorphous material made by melting sand, lime, also called calcium oxide, and sodium oxide at very high temperatures.

true

Obsidian refers to:

volcanic glass