- It is a mixture of two or more types of metallic silicates but the main component is silicon(IV) dioxide.
- Glass has the following properties:
- Transparent and not porous
- Inactive chemically
- Can be cleaned easily
- Good insulators of heat and electricity
- Hard but brittle
- Can withstand compression but not pressure
Composition: SiO2 – 70%, Na2O – 15%, CaO – 10%, Others – 4%
- Low melting point (700°C)
- Moldable into shapes
- Can withstand high heat
Uses: Glass containers, Glass panes, Mirrors, Lamps and bulbs, Plates and bowls Bottles
Lead glass (crystal)
Composition: SiO2 – 70%, Na2O – 20%, PbO – 10%
- High density and refractive index
- Glittering surface
- Low melting point (600°C)
Uses: Containers for drinks and fruit, Decorative glass and lamps, Crystal glassware, Lenses for spectacles
Borosilicate glass (Pyrex)
Composition: SiO2 – 80%, B2O3 – 13%, Na2O – 4%, AI203 – 2%
- Resistant to high heat and chemical reaction
- Does not break easily
- Allows infra-red rays but not ultra-violet rays
Uses: Glass apparatus in laboratories, Cooking utensils
Fused silicate glass
Composition: SiO2 – 99%, Other – 1%
- High melting point (1700°C)
- Allows ultraviolet light to pass through
- Difficult to melt or mould into shape
Uses: Scientific apparatus like lenses on, spectrometer, Optical lenses, Laboratory apparatus
- Ceramic is a substance that is made from clay and hardened by heat in a furnace maintained at a high temperature.
- Clay is composed of aluminosilicate with sand and iron(III) oxide as impurities.
- Examples of ceramics include
- The properties of ceramics include the following:
- The differences between the properties of ceramics, metals and non-metals are given below
|Hardness||Hard but malleable and ductile||Soft and brittle||Hard but brittle|
|Melting point||High||Low||Very high|
|Resistance to heat||High||Low||Very high|
|Heat and |
|Chemical reactions||Corrodes||Corrodes||Stable, does not corrode|
Comparing Glass and Ceramic
New Uses of Glass and Ceramics
- Photochromic glass is very sensitive to light.
- It darkens in the presence of bright light and lightens when the amount of sunlight lessens.
- Conducting glass is a type of glass which can conduct electricity. It is obtained by coating a thin layer of a conducting material around the glass, usually indium tin(IV) oxide.
- It is used in the making of Liquid Crystal Display (LCD)
Car Engine Block
- When clay is heated with magnesium oxide, the ceramic that is produced has a high resistance to heat.
- This material is used to build the engine blocks in cars as they can withstand high temperatures.
- Superconductors are electrical conductors which have almost zero (0) electrical resistance. Therefore, this conductor minimises the loss of electrical energy through heat.
- Yttrium barium copper oxide is a type of ceramic superconductor
- Superconductors are used to make magnets which are light but thousands of times stronger than the normal magnet.