Matter In Our Surroundings Notes Class 9th

The things around us have different shapes, sizes, and textures. Everything which is present in this universe is made up of material. The term allocated to it is matter. Everything is made up of matter from air to a small drop of water or a piece of sand. All these things occupy some space and have mass. Initially matter is classified into five elements: air, earth, fire, sky, and water. They are termed “Panch Tatva”. In the present time, scientists classify matter based upon its physical and chemical properties. Read this blog carefully you will surely get a lot of information regarding matter.

Matter Physical Nature

Two ideologies prevail with the physical nature of matter. As per the first belief, the matter is made up of blocks of chains. In the second belief, the matter is made up of sand-like particles. Let us discuss one example which will illustrate the nature of matter.

Take a biker of 100mL and fill it half with water. Now dissolve some sugar or salt into it  with the help of any rod or spoon. Now observe the level of water.Two questions may arise in your mind.

  • The first would be Where does the sugar or salt disappear?
  • The second question would be Does the water level change?

The Answer is when sugar or salt dissolves in water. The particles of salt or sugar assimilate into the vacant space between the particles of water.

Particles Characteristics

There is a lot of space between particles of matter. Matter particles are continuously moving. Therefore they possess kinetic energy. If the temperature rises the speed of the particles also increases and also kinetic energy also increases.

Attraction of Particles

There is a force between particles that binds them together. The strength of this force varies based upon the type of matter.

Types of States

The matter is mainly found in three types solid, liquid and gas. These types are formed because of the different nature of matter. Let us discuss each state :

Solid State

Solid has a definite shape and fixed volume. Solids can be seen with bare eyes. It has negligible compressibility. Solid can maintain their shape even when force is applied to them. They can break but it is hard to change their shape by applying force on them.

Examples of solids: are ice, sugar, Iron , Gold etc.

Liquid State

Liquids don’t have a fixed shape and fixed volume. They have the ability to change their shape like the shape of the container in which they were filled.

Liquids can flow and can change their shape. Liquids are not rigid. They are also known as fluid.

Examples are Water, Oil, Milk, alcohol and mercury.

Gas State

Gases are highly compressible in nature. The particles of gas are moving randomly here and there. The particles of gases hit each other due to this randomness. The pressure that gas exerts is only because of the force exerts by the particles per unit area on the walls of the container in which they are kept.

Examples are Oxygen, Hydrogen, Helium and Xenon.

Is Matter state change?

When the temperature rises the kinetic energy of particles in solid also rises . Due to an increase in kinetic energy, the particles start vibrating . The applied energy by the heat lowers the force of attraction between particles . This causes the shape change in solids and they turn into liquid. The temperature at which the state of a solid turns into liquid is known as the melting point . And the whole process is known as fusion . For instance, Ice melting point is 273.15K or 0 degrees Celcius or 32 degrees Faherheits.

Some matters like Dry Ice are directly converted into Gas from Solid. This phenomenon is called Sublimation.

Latent heat 

While the solid melts you must have observed that the temperature of the system doesn’t change when a melting point is reached. The word latent means hidden. Latent heat is the amount of energy required to change the state of 1 kg solid into liquid at atmospheric pressure at its melting point.

The water has more energy as compared to solid. When heat is supplied to water its particles move faster and a state reach at which they get enough energy. At that state, their force of attraction lowers and they turn into gas. The temperature at which a liquid turns into gas is called as boiling point. The water boiling point is 373K.


Effect of Change of pressure

The state of matter changes because of the difference in space of particles of matter. Now we will discuss what will happen if pressure is applied to gas that is enclosed in a cylinder. By increasing or decreasing the temperature gas can be turned to liquefy state. For example, Solid Carbon dioxide is stored under pressure. By decreasing the pressure this solid carbon dioxide can be turned into a gaseous state. Solid Carbon dioxide is known as dry ice because of this reason.

Dry Ice

Therefore the pressure or temperature can cause a change to the state of matter.


Water Evaporation

Temperature and pressure are not always required to change the state of matter. Sometimes the matter changes its state without applying temperature. To illustrate this take the example of water which is leftover without covering. It will slowly start turning into vapours. Another example is wet clothes drying up.

So we come up with the conclusion that matter particles always move and never take rest. Liquids have high kinetic energy because of the low fraction between particles of liquid. When a liquid turns into vapour at a temperature below then its melting point that is known as evaporation.

The evaporation rate increases by increasing –

Surface area, temperature, decrease in humidity, Increase in wind speed.

Evaporation Can Cause Cooling

In the uncovered vessel the liquid starts slowly evaporating. The liquid absorbs energy from the surroundings to gain the energy which it lost during the process of evaporation. This energy absorption from the atmosphere or surroundings causes cooling.

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