States of matter:
On the basis of physical state, all the matter can be classified into three groups: Solids, Liquids and Gases.
Properties of Solids, Liquids and Gases:
||Solids have a fixed shape and fixed volume
Liquids have fixed volume but they have no fixed shape
Gases have neither a fixed shape nor a fixed volume
Solids cannot be compressed much
Liquids cannot be compressed much
Gases can be compressed easily
Solids have high densities
Liquids have moderate to high densities
Gases have very low densities
Solids do not fill their container completely
Liquids do not fill their container completely
Gases fill their container completely
Solids do not flow
Liquids generally flow easily
Gases flow easily
For example: Ice, coal, wood, stone, iron, etc.
Water, milk, fruit juice, ink, petrol, etc.
Air, oxygen, hydrogen, nitrogen, steam, etc.
Why Solids, Liquids and Gases have different properties:
- According to the kinetic theory of matter, the particles of matter are in continuous motion and possess kinetic energy.
- Some forces of attraction also exist between the particles of matter. These are called inter particle forces. The forces of attraction tend to hold the particles together and control their movements.
The following properties of particles decide whether a given substance will exist as a solid, a liquid or a gas:
- The spaces between the particles: the spaces between the particles are the minimum in solids, a little more in liquids, and the maximum in gases.
- The force of attraction between particles: the forces of attraction between the particles are the strongest in solids, less strong in liquids and negligible in gases.
- The amount of movement of particles (or kinetic energy of particles): the movement of particles is the minimum in solids, more in liquids and the maximum in gases.
Test Your Knowledge
Fill in the blanks
1) On the basis of physical properties, matter is classified as _____, _______ and _____
2) On the basis of chemical properties, matter is classified as _____, _______ and _____.
3) The particles which make up matter are ____ and ____.
4) The zigzag movement of the small particles suspended in a liquid (or gas) is called _______
5) The particles of matter have __________________ between them.
6) The particles of matter are constantly _____
7) The best demonstration that particles of matter are constantly moving comes from the experiments on __________________ and ______.
8) The __________________ of attraction between the particles of the same substance is known as cohesion.
9) The force of __________________ between the particles of chalk is quite weak, the force of __________________ between the particles of ice is a bit stronger whereas the force of __________________ between the particles of iron nail is very, very strong.
10)The force of attraction is maximum in the particles of __________________ and minimum in the particles of a _____
11) Solids have a fixed shape and fixed __________________ Liquids have fixed __________________ but they have no fixed shape .Gases have neither a fixed shape nor a fixed __________________
12) According to the kinetic theory of matter, the particles of matter are in continuous motion and possess _______.
13)The forces of __________________ tend to hold the particles together and control their movements.
14) The spaces between the particles are the __________________ in solids, a little more in liquids, and the maximum in gases.
15) The forces of __________________ between the particles are the strongest in solids, less strong in liquids and negligible in gases.
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Plasma and Bose- Einstein Condensate:
Plasma and Bose- Einstein Condensate are two more states of mater apart from three other discusse dpreviously.
Scientists now say that there are actually five states of matter: Solid, Liquid, Gas, Plasma and Bose- Einstein Condensate.
- Plasma is a mixture of free electrons and ions. Plasma occurs naturally in the stars (including the sun).
- Inside the stars, the temperature is so high that the atoms break up. Some of the electrons break away from the atoms converting the rest of atoms into electrically charged particles called ions. This mixture of free electrons and ions in a star is called plasma.
- The sun and other stars glow because of the presence of plasma in them.
- Plasma can also be made on the earth by passing electricity through gases at very low pressure taking in a glass tube. The fluorescent tubes and neon sign bulbs form plasma when they are switched on.
Bose- Einstein Condensate
- In 1920 Indian physicist Satyendra Nath Bose had done some calculations for a fifth state of matter. Building on it calculations, Albert Einstein predicted a new state of matter- the Bose Einstein Condensate (BEC).
- The BEC is formed by cooling a gas of extremely low density (about one –hundred- thousandth the density of normal air) to super low temperature.
Test your Knowlegde
Fill in the blanks
1) __________________ gas can be liquefied by applying high pressure and lowering the temperature.
2) Decreasing the pressure and raising the temperature can change the state of __________________.
3) Solid carbon dioxide (dry ice) is stored under high __________________.
4) The process of a liquid changing into vapour (or gas) even its boiling point is called evaporation.
5) The wet clothes dry due to __________________ of water present in them.
6) The evaporation of a liquid depends mainly on the factors ______,Surface area, Humidity and __________________ speed
7) If the same liquid is kept in a test tube and in a china dish, then the liquid kept in the _____ evaporate more rapidly.
8) The amount of water present in air is represented by a term called _____
9) The cooling caused by __________________ is based on the fact that when a liquid evaporates, it draws or takes the latent heat of
vaporization from anything which it touches.
10) During hot __________________ days, water is usually kept in an earthen pot (called pitcher or matka) to keep it cool.
11)it is recommended to wear ______ in hot summer days to keep cool and comfortable.
12) ______________ vapor comes into the air from the evaporation of __________________ present in ponds, lakes, rivers and oceans.
13) ______________ vapor is alsogiven out by plants by the process of transpiration.
14) Plasma is a mixture of ____ and ____
15) BEC stands for ________________
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Class 9 Maths
Class 9 Science