Glass Forensics Vocabulary

Question 1

Becke line

Answer 1

Line created as refracted light becomes concentrated around the edges of the glass fragments

Question 2

Density

Answer 2

The ratio of the mass of an object to its volume

Question 3

Glass

Answer 3

A hard, amorphous, transparent material made by heating a mixture of sand and other additives

Question 4

Leaded glass

Answer 4

Glass containing lead oxide

Question 5

Obsidian

Answer 5

Volcanic glass

Question 6

Refraction

Answer 6

The change in the direction of light as it changes speeds when moving from one substance to another

Question 7

Refractive index

Answer 7

A measure of how light bends as it passes from one substance to another

Question 8

Silicon Dioxide

Answer 8

The chemical name for silica

Question 9

Amorphous

Answer 9

Without shaper or form

Question 10

What 2 things that make glass different

Answer 10

The additives or the way it is manufactured to break

Question 11

What is glass made out of

Answer 11

Silicon dioxide, soda lime and calcium oxide

Question 12

How does glass have individual characteristics? Give an example

Answer 12

If the glass has blood or fingerprints on it

Question 13

How does glass have class characteristics? Give an example

Answer 13

If you can tell what type of glass it is

Question 14

Amorphous solid

Answer 14

A solid with molecules randomly arranged

Question 15

What is a conchoidal fracture?

Answer 15

The curved fracture lines on the edge of radial or concentric cracks

Question 16

What can conchoidal cracks help determine

Answer 16

Help determine which side of the glass the impact came from

Question 17

What is the 3 R rule

Answer 17

Radial, right, reverse

Question 18

What are 2 ways you can determine the direction of a bullet entering through glass?

Answer 18

• Using the 3 R rule on a piece of broken glass with a radial fracture edge
• or look at the hole left by the projectile

Question 19

What are radial fractures

Answer 19

Fractures that radiate out from the central hole

Question 20

What are concentric fractures

Answer 20

Fractures that form circles

Question 21

What can radial fractures help determine

Answer 21

Order of hits and which side the glass is impacted

Question 22

Where is the laminated glass found and what’s one property?

Answer 22

Windshield of car

Piece of plastic between 2 pieces of glass

Question 23

Where is the lead crystal glass found and what’s one property?

Answer 23

Found in crystal glassware, or decorative glass art

-includes PbO to give it shine and weight

Question 24

Where is the Pyrex glass found and what’s one property?

Answer 24

Baking pans, headlights

- resistant to rapid heat change

Question 25

Where is the tempered glass found and what’s one property?

Answer 25

Cutting boards, car windows

- breaks into squares

Question 26

Where is the soda lime glass found and what’s one property?

Answer 26

Windows, bottles

- can be recycled easily