Identification Of Ceramics & Glasses

CONTENT

• Ceramic materials and properties

CERAMIC MATERIALS AND PROPERTIES

Ceramic is a hard brittle heat-resistant material made by firing a mixture of clay and chemicals at high temperature. The ceramic products are products made from clay and chemical materials.

Examples are clay pots, marbles, tiles , water-closet, water-jug, glass , water basins etc.

PROPERTIES OF CERAMIC MATERIALS

1. Ceramics are resistant to corrosion.
2. They can withstand very high temperature e.g. furnace and oven.
3. They are electrically resistant.
4. They are usually hard and strong.
5. They have compressive strength.
6. They can easily be molded when wet.
7. They can easily break when dropped on the ground.

EVALUATION

1. What is a ceramic?
   1. List five properties of ceramics.

GLASS MATERIALS AND PROPERTIES

Glass is a type of ceramic. Glass is a hard usually transparent material made from sand, lime, potash, soda and lead oxide. To produce glass, these raw materials are mixed and placed in a furnace and melted. It is then formed into the desired objects.

MAKING GLASS

Making of glass involves the following stages:

1. Mixing the raw materials;
2. Heating (firing) to produce molten glass;
3. Cooling to form rigid glass;
4. Heating again and allowing to cool gradually (annealing).

PROPERTIES OF GLASS

1. It is brittle,
2. It is transparent and
3. Resistant to corrosion.

Examples of glass products are cups, bottles, mirrors, glass tubes, electric bulbs, glass window, glass doors, eye glasses and lenses.

EVALUATION

1. What are the materials for making glass?
2. List three properties of glass.

WEEKEND ASSIGNMENT

1. Which of the following is not used in making glass?
2. Sand (b) lime (c) potash (d) clay
3. Glass is used to manufacture eye glasses and lenses because of this property. Choose from the options.  (a) Brittleness (b) resistance to corrosion (c) transparent (d) resistance to heat.
4. Which of the following is not used in making ceramics? (a) lime (c) cement (c) mud (d) clay.
5. The following are products of ceramics, except (a) flower vase (b) tiles (c) wash basin (d) electric bulb.

THEORY

1. What are ceramics and glass?
2. List two differences between the two.