Notes On States of Matter - CBSE Class 9 Science
Everything in this universe is made up of matter. Matter is defined as any substance that has mass, occupies volume and may be perceived by the senses. Exception: Phenomena like heat, electricity, light, sound, magnetism, vaccum, shadow are not matter because they have no mass and does not takes up space. Matter is made up of small particles. The particles of the matter are very small. We cannot see them even with a high power microscope. The particles of the matter have following characteristics Matter is made up of small particles. The particles in the matter have spaces between them. This space is called inter molecular space. The particles in the matter are moving in nature, because the particles of a matter have kinetic energy. The motion of the particles increases with an increase in temperature. The particles in the matter attract each other, but this mutual force of attraction is effective only when the particles are very close to each other. In solids the particles are closely packed and hence they have greater intermolecular forces attractions while in gases, the particles are loosely held. Hence they have weak forces of attractions. Diffusion The intermixing of the particles of two or more substances on their own is called diffusion. The diffusion is faster in gases. The rate of diffusion is different in different gases. Lighter gas diffuses at faster rate than heavier gases. Diffusion is also takes place in liquids as well as solids. However the rate of diffusion in solids is fairly low. Diffusion in liquids is slower than gases because the particle of liquids moves slowly Factors effecting diffusion Density Rate of diffusion is inversely proportional to the density of a gas or liquid. Higher the density lesser will be the rate of diffusion. Temperature Rate of diffusion is directly proportional to the temperature. As the temperature increase the kinetic energy of the particles increases and they move with greater speed resulting in an increased rate of diffusion. Classification of matter On the basis of its state, matter has been classified by the scientists into five states namely - solid, liquid, gas, plasma and Bose-Einstein Condensate. Among these states, the most common states of matter that exists around us are as solids, liquids and gases. Solid state When the particles are bound together firmly they form solids. In solids, the particles simply vibrate about their fixed positions, because their kinetic energy is low and not enough to let them break away from their mutual force of attraction. Therefore, solids have definite shapes, volumes and are not compressible. For the same reason they do not flow, or diffuse. Exceptions A rubber band can be stretched under force and regains the same shape when the force is removed. If the same rubber band is stretched maximum with excessive force it breaks. Sponge is another example of solid, which has minute holes in which the air is trapped. When it is pressed with a hand the air is expelled out and it gets compressed. Liquid state: In liquids, the kinetic energies of the particles are more than in solids, and the particles are not bound to any fixed positions. They move around freely, at random, throughout the liquid. However, they do not have enough kinetic energy to break out of the boundary of the liquid mass. That explains why liquids do not have definite shapes, and flow or diffuse freely, but they do have definite volumes. Also, compared to solids, there are more spaces between the particles of liquids, but not enough to make liquids compressible. Gaseous state In gases, the particles are not packed together at all, because their kinetic energies are high enough to let them break away from any boundaries. They are free to move around in random motion. That is why gases have no definite shape or volume, and they flow and diffuse easily. They collide with each other, and with the walls of their container. That’s how a gas exerts pressure on its container. Also, because the spaces between the particles are large, gases are highly compressible. Differences between solids, liquids and gases        Property          Solids           Liquids        Gases Volume and shape Definite shape and volume Shape of container and definite volume No definite shape and volume Compressibility Cannot be compressed, except porous solids Cannot be compressed Can be compressed easily Flow Particles do not flow Particles flow Particles flow easily Diffusion Diffuse lowly Diffuse fast Diffuse very fast Force of attraction between particles High Less Very less Inter-molecular space Very less More Large Plasma state Plasma is the fourth state of matter. Plasma is similar to the gaseous state. The state consists of super energetic and super excited particles in the form of ionized gases. Plasma is made by heating a gas it lose all its electrons .it is present in stars .The plasma is produced in  sun and stars because of very high temperature. The sun and stars glow because of the presence of plasma in them. The fluorescent tube and neon sign bulbs consist of plasma. The gas present inside these bulbs and tubes is inert gas. When electricity is passed through them the gas gets ionised and charged. This charging up creates a glowing plasma, having a special color depending on the nature of gas. Bose-Einstein condensates The theory of BEC was developed by Indian physicist Satyendra Nath Bose in 1920 was developed the theory of BEC. Later 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. Bose-Einstein condensate refers to the collapse of atoms into a single quantum state. It is found at low temperatures when atoms are not able to move at all.

#### Summary

Everything in this universe is made up of matter. Matter is defined as any substance that has mass, occupies volume and may be perceived by the senses. Exception: Phenomena like heat, electricity, light, sound, magnetism, vaccum, shadow are not matter because they have no mass and does not takes up space. Matter is made up of small particles. The particles of the matter are very small. We cannot see them even with a high power microscope. The particles of the matter have following characteristics Matter is made up of small particles. The particles in the matter have spaces between them. This space is called inter molecular space. The particles in the matter are moving in nature, because the particles of a matter have kinetic energy. The motion of the particles increases with an increase in temperature. The particles in the matter attract each other, but this mutual force of attraction is effective only when the particles are very close to each other. In solids the particles are closely packed and hence they have greater intermolecular forces attractions while in gases, the particles are loosely held. Hence they have weak forces of attractions. Diffusion The intermixing of the particles of two or more substances on their own is called diffusion. The diffusion is faster in gases. The rate of diffusion is different in different gases. Lighter gas diffuses at faster rate than heavier gases. Diffusion is also takes place in liquids as well as solids. However the rate of diffusion in solids is fairly low. Diffusion in liquids is slower than gases because the particle of liquids moves slowly Factors effecting diffusion Density Rate of diffusion is inversely proportional to the density of a gas or liquid. Higher the density lesser will be the rate of diffusion. Temperature Rate of diffusion is directly proportional to the temperature. As the temperature increase the kinetic energy of the particles increases and they move with greater speed resulting in an increased rate of diffusion. Classification of matter On the basis of its state, matter has been classified by the scientists into five states namely - solid, liquid, gas, plasma and Bose-Einstein Condensate. Among these states, the most common states of matter that exists around us are as solids, liquids and gases. Solid state When the particles are bound together firmly they form solids. In solids, the particles simply vibrate about their fixed positions, because their kinetic energy is low and not enough to let them break away from their mutual force of attraction. Therefore, solids have definite shapes, volumes and are not compressible. For the same reason they do not flow, or diffuse. Exceptions A rubber band can be stretched under force and regains the same shape when the force is removed. If the same rubber band is stretched maximum with excessive force it breaks. Sponge is another example of solid, which has minute holes in which the air is trapped. When it is pressed with a hand the air is expelled out and it gets compressed. Liquid state: In liquids, the kinetic energies of the particles are more than in solids, and the particles are not bound to any fixed positions. They move around freely, at random, throughout the liquid. However, they do not have enough kinetic energy to break out of the boundary of the liquid mass. That explains why liquids do not have definite shapes, and flow or diffuse freely, but they do have definite volumes. Also, compared to solids, there are more spaces between the particles of liquids, but not enough to make liquids compressible. Gaseous state In gases, the particles are not packed together at all, because their kinetic energies are high enough to let them break away from any boundaries. They are free to move around in random motion. That is why gases have no definite shape or volume, and they flow and diffuse easily. They collide with each other, and with the walls of their container. That’s how a gas exerts pressure on its container. Also, because the spaces between the particles are large, gases are highly compressible. Differences between solids, liquids and gases        Property          Solids           Liquids        Gases Volume and shape Definite shape and volume Shape of container and definite volume No definite shape and volume Compressibility Cannot be compressed, except porous solids Cannot be compressed Can be compressed easily Flow Particles do not flow Particles flow Particles flow easily Diffusion Diffuse lowly Diffuse fast Diffuse very fast Force of attraction between particles High Less Very less Inter-molecular space Very less More Large Plasma state Plasma is the fourth state of matter. Plasma is similar to the gaseous state. The state consists of super energetic and super excited particles in the form of ionized gases. Plasma is made by heating a gas it lose all its electrons .it is present in stars .The plasma is produced in  sun and stars because of very high temperature. The sun and stars glow because of the presence of plasma in them. The fluorescent tube and neon sign bulbs consist of plasma. The gas present inside these bulbs and tubes is inert gas. When electricity is passed through them the gas gets ionised and charged. This charging up creates a glowing plasma, having a special color depending on the nature of gas. Bose-Einstein condensates The theory of BEC was developed by Indian physicist Satyendra Nath Bose in 1920 was developed the theory of BEC. Later 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. Bose-Einstein condensate refers to the collapse of atoms into a single quantum state. It is found at low temperatures when atoms are not able to move at all.

#### Activities

Activity 1 Wikispaces.com has created an interactive activity on "States of Matter". The main objective of this activity is to show molecular motions in different states of matter. Go To Activity Activity 2 Unh.edu has created a wonderful video on "Plasma State". This video explains how plasma is formed. Student can also learn more about location of plasma. Go To Activity Activity 3 Scienceunleashed has created an interactive activity on "States of Matter". This activity explains characteristics of different states of matter. Go To Activity Activity 4 Theworldschoolindia.com has created an educational video on "Nature of matter". This video explains the various states matter along with their properties. Go To Activity Activity 5 Phet.colorado has developed a simulation to understand the concept States of Matter. This simulation describe a molecular model for solids, liquids, and gases and also describe how changing temperature and changing volume affect the behavior of the molecules. Go To Activity

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