Science Notes # 5

• Everything in this universe is made up of material named matter.
• Early Indian Philosophers classified matter in the form of 5 basic elements - the Panch Tatva.

1. air
2. earth
3. water
4. fire
5. sky

• The matter around us exist in 3 different states - solid, liquid and Gas

Solids:

• Have a definite shape, distinct boundaries and fixed volume.
• have tendency to maintain their shape when subjected to outside force.
• they are rigid

Liquids:

1. have no fixed shape
2. have a fixed volume
3. they can be called fluids as they are not rigid.
4. solids, liquids, gases can diffuse into liquids.

Gaseous state:

• Gases are highly commpressible as compared to solids and liquids.
• In the Gaseous state, the particles move about randomly at high speed.

• Water can exist in 3 states of matter

1. solid as Ice
2. Liquid as water
3. Gas as water vapour

• The melting point of a solid is an indication of the strength of the force of attraction between its particles.
• The temperature at which a solid melts to become a liquid at the atmospheric pressure is called its melting point.
• The melting point of Ice is 273.16K
• The process of melting,i.e. change of solid state into liquid is also known as fusion.
• The amount of heat energy that is required to change 1kg of a solid into liquid at atmospheric pressure at its melting point is known as the latent heat of fusion.
• The temperature at which a liquid state starts boiling at the atmospheric pressure is known as its boiling point.
• A change of state directly from solid to gas without changing into liquid state ( or vice versa) is called sublimation.
• change of state from solid to liquid is fusion.
• Change of state from liquid to gas is vaporisation.
• Change of state from gas to liquid is condensation.
• The phenomenon of change of liquid into vapours at any temperature below its boiling point is called Evaporation.
• Humidity is the amount of water vapour present in air.
• Now scientists are talking about 2 other states of matter. They are - Plasma and Bose Einstein condensate.
• Plasma is the state consists of super energetic and super excited particles.
• The S.I unit of Volume is cubic meter.
• The S.I unit of temperature is Kelvin.
• The S.I unit of weight is Newton
• The S.I unit of Density is Kilogram per cubic meter.
• The S.I unit of Pressure is Pascal.

Source: Science IX NCERT chapter 1