Module 1: Assessment Quiz

Module: U12M1 - Glass Science and Safety Passing Score: 70%

---

What is the primary chemical component of all common glass types?

Silica (SiO₂)

Calcium carbonate (CaCO₃)

Sodium chloride (NaCl)

Aluminum oxide (Al₂O₃)

Submit

Explanation: Silica (SiO₂) forms the fundamental network structure of glass, typically comprising 50-99% of the composition depending on glass type.

Which glass type has the lowest coefficient of thermal expansion (CTE)?

Fused silica (0.5 x 10⁻⁶ /K)

Borosilicate (3.3 x 10⁻⁶ /K)

Soda-lime (9 x 10⁻⁶ /K)

Lead glass (9-10 x 10⁻⁶ /K)

Submit

Explanation: Fused silica has the lowest CTE at 0.5 x 10⁻⁶ /K, making it virtually immune to thermal shock. This is because it is nearly pure SiO₂ with no network modifiers to disrupt the silica structure.

What happens when soda-lime glass and borosilicate glass are fused together in a kiln?

The piece will crack or craze due to CTE mismatch during cooling

They fuse successfully with no issues

The borosilicate melts before the soda-lime

The colors blend together but the bond is weak

Submit

Explanation: Soda-lime (CTE 9) and borosilicate (CTE 3.3) have incompatible thermal expansion rates. During cooling, the soda-lime contracts more than the borosilicate, creating internal stress that causes crazing or complete breakage.

What is the purpose of the annealing process in glass working?

To relieve internal thermal stress by controlled heating and slow cooling

To increase the hardness of the glass surface

To add color to the glass through chemical reaction

To reduce the melting point for future work

Submit

Explanation: Annealing heats glass to its annealing point (e.g., 510°C for soda-lime) and holds it there to allow internal stress to relieve through atomic rearrangement, then cools slowly to prevent new stress from forming.

At what temperature does soda-lime glass reach its annealing point?

510°C (950°F)

400°C (750°F)

650°C (1200°F)

1050°C (1920°F)

Submit

Explanation: The annealing point for soda-lime glass is approximately 510°C. At this temperature, internal stress relief occurs over a timescale of hours. Below the strain point (475°C), glass becomes permanently stressed.

Which type of eye protection is required when viewing the interior of a hot kiln?

UV/IR safety glasses or goggles that filter 99%+ UV and infrared radiation

Standard safety glasses with clear lenses

Prescription eyeglasses with polycarbonate lenses

Welding goggles rated for shade 14

Submit

Explanation: Hot kilns and glass emit significant infrared radiation that causes cumulative, irreversible eye damage including cataracts. UV/IR-rated eye protection filtering 99%+ of UV and IR is mandatory for all kiln viewing and torch work.

What is the primary respiratory hazard when grinding glass?

Silica dust inhalation, which can cause silicosis over time

Glass vapor that irritates the throat

Carbon monoxide released from heated glass

Lead fumes from all glass types

Submit

Explanation: Grinding glass produces fine silica dust particles. Chronic inhalation causes silicosis, a progressive lung fibrosis with 10-20 year latency. This is a silent hazard with no acute symptoms. Wet grinding is the primary prevention method.

What is the correct first aid response for a thermal burn from hot glass?

Run cool (not cold) water over the burn for 10-20 minutes

Apply ice directly to the burn for rapid cooling

Cover the burn with butter or oil to soothe the skin

Wrap tightly in gauze and apply pressure

Submit

Explanation: Cool running water for 10-20 minutes is the correct response. Ice causes additional tissue damage. Oil and butter trap heat. The goal is gradual cooling without secondary injury.

Why is lead glass considered a critical hazard material?

Lead is neurotoxic and bioaccumulative; dust from grinding contains lead

Lead glass shatters more violently than other glass types

Lead glass emits radiation when heated

Lead glass produces toxic chlorine gas when cut

Submit

Explanation: Lead oxide (PbO) in lead glass is neurotoxic and bioaccumulative. Even small exposures contribute to lifetime lead burden. Grinding produces lead-containing dust requiring wet grinding, HEPA filtration, and PAPR protection.

What does the thermal color "bright cherry red" indicate about soda-lime glass temperature?

800-900°C — extremely hot, no contact permitted

400-500°C — caution, gloves required

500-650°C — hot, gloves and face shield needed

1000°C+ — molten, do not approach

Submit

Explanation: Bright cherry red indicates 800-900°C (1470-1650°F). At this temperature, glass is extremely hot and any contact will cause instant severe burns. Full PPE is required and direct contact is prohibited.

Which glass type is recommended for torch/lamp work?

Borosilicate, because it resists thermal shock and can cool more rapidly

Soda-lime, because it has a lower melting point

Lead glass, because it is softest and easiest to shape

Fused silica, because it has the highest melting point

Submit

Explanation: Borosilicate's low CTE (3.3 x 10⁻⁶ /K) gives it superior thermal shock resistance, allowing it to withstand the rapid heating and cooling cycles inherent in torch work without cracking.

What is the minimum clearance required around a hot kiln during operation?

3 feet on all sides

1 foot on all sides

6 inches from the front only

No clearance is needed if the kiln has insulated walls

Submit

Explanation: A 3-foot clearance perimeter is required around hot kilns because heat radiates outward from all surfaces. This zone must be marked with warning tape or signs and kept clear of personnel and materials.

What is thermal shock in glass working?

Rapid temperature change causing the surface and interior to expand/contract at different rates, shattering the glass

Slow heating that gradually weakens the glass structure over time

Electrical discharge through glass caused by static buildup

Chemical reaction between glass and water at high temperatures

Submit

Explanation: Thermal shock occurs when glass experiences a sudden temperature change. The surface cools (or heats) rapidly while the interior remains at a different temperature, creating extreme stress that exceeds the glass's strength, causing instant fracture.

What is the correct PPE donning sequence before kiln or torch work?

Thermal gloves → UV/IR glasses → face shield → apron → secure hair and clothing

Apron → face shield → gloves → glasses → check hair

UV/IR glasses → apron → gloves → face shield → check hair

Face shield → thermal gloves → apron → UV/IR glasses → secure hair

Submit

Explanation: The correct sequence ensures extremity protection first (gloves), then eye protection (glasses), then face coverage (shield), then body protection (apron), and finally securing loose items. This order minimizes exposure during the donning process itself.