IB Design Technology 4.2c Glass Notes

Glass in Design

Understanding Glass: Properties and Uses

1. Glass is a unique material with many different properties that make it useful in construction, packaging, technology, and design.
2. Think of it like a superhero material—strong in some ways but fragile in others, and with different “powers” depending on its composition.

Color and Composition

1. Glass can change color when metallic oxides (special chemicals) are added.
   1. Different elements create different colors:
      1. Iron makes glass green.

1. Sulfur makes it yellow or brown.

1. Copper makes it blue.

1. Chromium gives a deep green shade.

1. Example: Stained glass windows in churches or colored glass bottles (like green wine bottles) are made using these additives.

Transparency

1. One of glass’s best features is that it lets light through, making it ideal for windows, skylights, and display cases.

1. It’s widely used in architecture to bring in natural light, reducing the need for artificial lighting.

1. Example: Transparent glass is used in storage containers so you can see what’s inside without opening them.

Strength and Brittleness

1. Glass has high compressive strength (it can handle a lot of weight pressing down on it), but low tensile strength (it breaks easily if pulled or bent).
2. It’s brittle, meaning it can shatter easily, but this can be reduced with special treatments:
   1. Tempered glass is heated and cooled rapidly to make it stronger (used in car windows and shower doors).

1. Laminated glass has layers that hold it together when cracked (used in car windshields for safety).

Hardness

1. Glass is resistant to scratching, making it ideal for smartphone screens (like Gorilla Glass) and other surfaces that need to stay smooth and clear.

1. It’s also used for high-durability applications, like watch faces and protective eyewear.

Nonporous and Chemically Inert

1. Glass doesn’t absorb liquids or react with most chemicals, making it perfect for food storage and lab equipment.
2. It’s used in chemical-resistant lab glassware (like beakers) and airtight jars for storing food.

Types of Glass and Their Uses

1. Glass isn’t just one type—it comes in different forms, each with its own strengths and weaknesses.
2. Think of it like different types of fabric: some are soft and stretchy, some are tough and durable, and others are made for special uses.

Annealed Glass (Basic Glass)

1. The most common and untreated type of glass.
2. Made by slowly cooling the glass to relieve internal stress.
3. Weak and breaks into large, sharp shards, which can be dangerous.
4. Used in: Picture frames, standard windows (where safety isn’t a big concern).
5. Analogy: Think of annealed glass like an unfitted bedsheet—it’s simple and does the job, but it doesn’t hold up under stress.

Tempered Glass (Stronger and Safer)

1. Made by rapidly heating and cooling the glass to increase its strength.
2. Shatters into small, blunt pieces instead of sharp shards, reducing injury risk.
3. Used in: Car windows, shower doors, phone screen protectors.
4. Analogy: It’s like a tempered chocolate bar—stronger, but when it breaks, it crumbles into small, harmless pieces instead of sharp chunks.

Laminated Glass (Safety Glass)

1. Made of two glass layers with a plastic interlayer sandwiched between.
2. Holds together even when shattered, preventing dangerous breakage.
3. Used in: Car windshields, glass railings, and places needing impact resistance.
4. Bonus: Blocks UV rays, protecting interiors from sun damage.
5. Analogy: Think of it like a PB&J sandwich—if you press down on it, the layers stay together because of the sticky center.

Borosilicate Glass (Heat-Resistant Glass)

1. Resistant to heat and sudden temperature changes, meaning it won’t crack easily.
2. Used in: Lab glassware (beakers, test tubes), Pyrex kitchenware, and some high-end lighting.
3. Durable and chemically resistant, making it ideal for scientific and cooking use.
4. Analogy: It’s like a firefighter’s uniform—able to handle extreme temperatures without breaking down.

Soda-Lime Glass (Everyday Glass)

1. Most common and cost-effective type of glass.
2. Easily recyclable, making it more eco-friendly.
3. Used in: Windows, drink bottles, jars.
4. Weak against heat shock—sudden temperature changes can cause it to shatter.
5. Analogy: Think of it like cheap plastic cups—good for everyday use, but they crack easily if exposed to extreme temperatures.

Fiberglass (Strong and Flexible)

1. Made from woven glass strands mixed with resin, making it lightweight yet strong.
2. Waterproof and weather-resistant, making it useful for outdoor and industrial use.
3. Used in: Boat hulls, tent poles, fishing rods, car body parts.
4. Analogy: It’s like a spider web—thin but incredibly strong and flexible.

Environmental Considerations

1. Most glass is recyclable, which helps reduce waste and energy use.
2. Some types (like fiberglass or laminated glass) are harder to recycle because they have mixed materials.
3. Making glass requires a lot of energy, so its environmental impact depends on the type and production process.

Reflection