Special properties of solids
- Regidity: Rigidity is the property by which solid offers resistance to external forces. Examples of rigid bodies are iron, plutonium, stone, glass etc.
- Hardness: It is a property by which a solid body of force resistance to being cut or to be scratched by another substance.
- Brittleness: It is a property by which a solid substance can be broken into smaller pieces easily by hammering.
- Malleability: It is the property by which a solid substance can be hammered into thin sheets, plates easily.
- Ductility: It is a property by which a solid substance can be drawn into thin wires. In general , all metals are ductile. Ductility and also increases with rise in temperature .
Special properties of liquid
- Liquids have no shape of their own.
- Liquids are incompressible: Liquids possesses a definite volume.
- Liquids maintain their level: Due to the highly molecule of motion of a liquid, it always flows from a higher to a lower level. The free surface of a liquid at rest is horizontal.
- Liquid purchases surface tension: Surface tension is the property by which the free surface of a liquid behaves as a stretched membrane. Water has more surface tension than oil. Insects can freely walk on the surface of a stagnant water.
- Liquid exert pressure: Liquids exert pressure on the walls of the containing vessel. And this pressure increases with depth.
- Viscosity: The property of a liquid by virtue of which it offers a resistance to the flow is called viscosity. Viscosity is the internal friction of a fluid. Water at the centre of the pipe moves faster. This property, similar to friction, is sometimes called internal friction.
Special properties of Gasses
- Gases have no definite shape or size: In case of Gasses, the inter molecule attractions are negligible and the inter molecule distances are large.
- Gases have no free surface: The Gasses expand freely and occupied the complete volume of the containing vessel. Hence gases do not have any free surface.
- Gases are highly compressible: The volume of Gas can be reduced by the application of pressure. The Gasses can be highly compressed. Compressed oxygen cylinders in hospitals, compressed hydrogen bags and airships and compressed air bags in submarines are some of the examples of highly compressed gases.
Role of vacuum: The vacuum plays a constant and practical role in our life today. If the air were not removed from the ordinary electric bulb you use in your lamp, the head frozen in the area would cause the little filament wire inside the bulb to burn out very soon. Many of the tubes in the older radios of vacuum tubes. In some other types of bulbs and tubes, other gases are pumped in after the air has been pumped out.