CogKnoSys

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Physical

Ceramics and Glass

Ceramics and glass are hard, heat-resistant materials made from nonmetallic substances, such as clay and silica, using high heat.

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The idea

Ceramics and glass are hard materials made from inorganic, nonmetallic substances, usually with the help of great heat. A ceramic is made by shaping a material such as clay and then firing it at a high temperature. The result is hard and brittle, and it resists heat and corrosion. Common ceramics include earthenware, porcelain and brick. The word ceramic comes from an Ancient Greek word meaning "of or for pottery."

Glass is an amorphous solid, which means its atoms are not arranged in a regular crystal pattern. It is usually made by cooling melted material very quickly. Common soda-lime glass is made of around 70 percent silica, mixed with other ingredients. Because glass is often transparent and does not react easily with other chemicals, it is used for windows, tableware and lenses. Some glass forms in nature, such as the volcanic glass called obsidian.

The two materials often work together. A glaze is a thin, glassy coating fired onto a ceramic surface, which makes it smooth and colored and less porous. Glass itself can be colored by adding metal salts, which is how stained glass windows get their colors. Thin glass fibers are also matted into glass wool to trap air as insulation, or used to strengthen plastic in fiberglass.

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Question 1 of 3

What does it mean that glass is amorphous?

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Composition

what it's made of

  • Clay and other minerals — Inorganic, nonmetallic raw materials that are shaped before firing.
  • Firing — Heating a shaped ceramic to a high temperature so that it hardens.
  • Glaze — A glassy coating fired onto a ceramic to make its surface smooth, colored and less porous.
  • Silica — The main ingredient of common soda-lime glass.
  • Rapid cooling — Glass usually forms when molten material is cooled quickly, before crystals can grow.

Connection

how it relates

Under Materials

Related

  1. Igneous Rockstrength 70 of 100

    Obsidian is a natural glass that forms when lava cools too quickly for crystals to grow.

  2. Thermal Energystrength 60 of 100

    Ceramics are hardened by firing at high temperatures, and glass is made by melting and then cooling material.

  3. Creative Expressionstrength 50 of 100

    Pottery, glazes and stained glass have long been ways for people to make art.

Change

how and why it evolves

Past
Humans appear to have begun making ceramics at least 26,000 years ago, and the earliest ones archaeologists have found are sculpted figures, not dishes. Glassmaking dates back to at least 3600 BC in Mesopotamia, Egypt or Syria, and the earliest known glass objects were beads.
Now
Ceramics now include household, industrial and building products, as well as advanced materials such as semiconductors. Glass fibers carry signals as optical fibers in communication networks.
Next
Engineers will likely keep developing new ceramics and glasses for electronics, energy and medicine, building on the same basic recipes of minerals and heat.

Knowledge you can walk. Read the idea, then step up, across or down.

Ceramics and Glass

Ceramics and glass are hard, heat-resistant materials made from nonmetallic substances, such as clay and silica, using high heat.

Learn, discuss, create, buy or invest

The idea

Ceramics and glass are hard materials made from inorganic, nonmetallic substances, usually with the help of great heat. A ceramic is made by shaping a material such as clay and then firing it at a high temperature. The result is hard and brittle, and it resists heat and corrosion. Common ceramics include earthenware, porcelain and brick. The word ceramic comes from an Ancient Greek word meaning "of or for pottery."

Glass is an amorphous solid, which means its atoms are not arranged in a regular crystal pattern. It is usually made by cooling melted material very quickly. Common soda-lime glass is made of around 70 percent silica, mixed with other ingredients. Because glass is often transparent and does not react easily with other chemicals, it is used for windows, tableware and lenses. Some glass forms in nature, such as the volcanic glass called obsidian.

The two materials often work together. A glaze is a thin, glassy coating fired onto a ceramic surface, which makes it smooth and colored and less porous. Glass itself can be colored by adding metal salts, which is how stained glass windows get their colors. Thin glass fibers are also matted into glass wool to trap air as insulation, or used to strengthen plastic in fiberglass.

Check yourself

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