Every think we can feel, touch and see are matter. Example: Air, water, milk, stone etc. Everything are made up of atoms. Atoms are the tiny particles which are present around us. The particles which makes matter are always in zig zag motion (called Brownian motion). This motion increases on increasing the temperature. Some examples showing Brownian motion are:
- Dust particles in air are shown by sunlight beam etc.
- Water is made up of tiny particles which are moving very fast. The pollen grain moving on the surface of water because they are constantly being hit by the fast moving tiny particles of water.
Characteristics of matter
- All matter is made up of Particles.
- The particles of matter are very small.
- The particles of matter have space between them.
- The particles of matter attract each other and moving constantly.
Types of matter
Matter is of three types:
- Solid: Solid have strong force of attraction between the small particles of it which holds them together in a fixed position. solid have fixed shape and fixed volume.
Properties of Solid :
- Solid cannot be compressed
- They have high density
- They don't have tendency to flow
- Liquid: The force of attraction between particles are less than solid. The space between particles are slightly more then the solid. The position of the particles in liquid are not in fixed position. The particles can move from one place to another so that they have more kinetic energy . Liquid have fixed volume but they have no fixed shape instead of that they take the shape of container in which they are filled.
Properties of Liquid :
- Liquid cannot be compressed very much.
- They are less dense then solid.
- They can flow.
- Gases: The force of attraction between the particles of gas is very weak and the space between the particles of gas is very long so they can move in any direction. They have maximum K.E (kinetic energy). Gas have neither fixed shape nor fixed volume.
Properties of Liquid :
- Gas can b compressed easily (eg. LPG, CNG).
- They have low density.
- Gas can flow easily.
Change of state of matter
Matter can exist in three physical state: Solid , Liquid and Gaseous state change of state of matter is dependent on temperature and pressure for eg. Water is in solid state (i.e. ice) at 0°C at atmospheric pressure , when we increase temperature ice will be converted into liquid state till boiling point after then at 100° C water will b converted into gas at atmospheric pressure.
Change of state is done by various method some of these are :
- Melting: It is a process in which solid changes into liquid when when increasing the temperature. The temperature at which solid melts and change into liquid at atmospheric pressure is called Melting Point. 0°C is the melting point of ice.
- Boiling: It is the process in which liquid changes into gas when when increasing the temperature. The temperature at which liquid boils and change into gas at atmospheric pressure is called Boiling Point. 100°C is the boiling point of water. i.e water converts into vapour at 100°C.
- Condensation: The process in which gas converts into liquid is called condensation. It is reverse of boiling.
- Freezing: The process in which liquid converts into solid is called freezing. It is reverse of melting.
- Sublimation: Change of solid directly into gas on heating and gas into solid on cooling is called sublimation. The common substance which undergo sublimation are Aluminum chloride, Iodine, Camphor, Naphthalene and dry ice etc.
- Evaporation: When liquid turns into vapour is called evaporation. The evaporation of liquid depends mainly on some factor like temperature, surface area, humidity, wind speed
The amount of heat which is required to change the state of substance is called latent heat.