Glass

Question 1

Glass definition

Answer 1

An inorganic product of fusion which has cooled to a product without crystiliazation

Question 2

Glass is made from

Answer 2

Silica

Question 3

Types of glass (5)

Answer 3

Tempered
Boroscoilate
Soda lime
Laminated
Float

Question 4

Tempered glass

Answer 4

POE glass , tough, stronger , car windows

Question 5

Borosilicate

Answer 5

Strongest , least dense , kitchen glasswear , melts at a high temperature

Question 6

Soda lime

Answer 6

Common , glass bottles , cheap

Question 7

laminated

Answer 7

safety glass , bullet resistant , bomb impacts

Question 8

Where do you collect glass (3)

Answer 8

hair
clothings
POE

Question 9

Collection methods (4)

Answer 9

tweezering
vacuuming
tape lifting
combing

1cm squares at least 6

Question 10

How to preserve glass collection 3

Answer 10

Cardboard box
Plastic vials
Drug wraps
make sure evidence is dry before collection

Question 11

Microscopic examination - glass 4

Answer 11

colour
thickness
surface
flatness

Question 12

Glass refractive index

Answer 12

1.400 — 1.560

Question 13

What tools do you use to observe glass thickness

Answer 13

capillary and verminer scale

Question 14

Hot stage examination

Answer 14

control variables - temperatures, light wavelength
grind sample in pestle and mortar and immerse in oil
mount on microscopic slide and heat the stage
observe glass in screen

Question 15

Two tests for R.I. (2)

Answer 15

Becke line test
relief test

Question 16

Becke line test

Answer 16

Does oil or glass have the higher R.I

halo inside = glass has higher RI
halo outside = Oil has higher RI

Question 17

Relief test :

Answer 17

How close is sample to oil in terms of RI
high relief - strong outline
low refried - faint /barely visible