Many solids are crystals A solid in which the atoms are arranged in a regular pattern Sodium chloride.

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Presentation transcript:

Many solids are crystals A solid in which the atoms are arranged in a regular pattern Sodium chloride

Glass is an amorphous solid. A solid in which the atoms are in no order. It is also brittle and shows a conchoidal fracture pattern, has hardness, and elasticity of shape.

Types of Glass a. Soda-lime glass most common commercial glass (90% of total production) least expensive

Soda-lime glass is used for:

b. Borosilicate glass strong heat resistant contains boron oxides

c. Tempered Glass made stronger than soda-lime glass by rapid heating and cooling; used for side and rear windows in cars

Also used in…

Tempered glass breaks into….

d. Laminated glass For windshields

e. Soda-lead glass commonly called crystal or lead glass, expensive widely used for the finest tableware and art objects.

Comparison a. Individual evidence (jigsaw fit)

b. Class characteristics 1. Flotation Used to find the density of glass by floating glass particles in liquids of known densities.

Density Mass per unit of volume Density = Mass/Volume

2. Immersion method – used to find the Refractive Index of glass

Refractive index (RI) Formula RI = velocity of light in vacuum velocity of light in medium The RI of water at room temperature is 1.333

When the Becke line disappears MATCH POINT The point at which the Becke line disappears The RI of the glass = RI of the oil

© Hot Stage microscope Heats the Immersion oil (changes the RI of the oil)

GRIM 2

Annealing Slowly heating & cooling of glass Makes glass more durable

Data bank Densities Refractive indices Relative frequencies in the glass pop of US

Fragments a. Types (1) Radial fractures

(2) Concentric fractures

b. First Fractures Form on the side of the glass OPPOSITE the side of the penetrating object Radial fractures

c. Next Fracture Forms on the SAME side of the glass as the penetrating force Forms concentric fractures

d. Stress markings

3 R Rule R adial cracks form a R ight angle on the R everse side of the force

Fracture Termination Which bullet hole was made first?

Also know… Blowback; the backscattering of particles toward the direction of the force. A high-velocity projectile leaves a wider hole on the exit side of the glass