Physical Nature of Matter (Solids, Liquids, Gases and their characteristics)

Everything in the universe that has mass and occupies space is called matter. So, everything around us is generally defined as matter. Very, broadly matter is classified into solids, liquids and gases. For a long time, the smallest building block of matter was thought to be ‘atoms’, which have the same chemical nature as the observable form of matter. For example, an atom of carbon has the same chemical properties as, say a kilo of solid carbon. However, later smaller units of matter have been discovered which do not display these chemical characteristics. In this article, we look at how this matter exists, in what state does it exist, what is the smallest unit or building block of matter. Read the entire article to learn more about the physical nature of matter.

Learn Nature of Matter

Physical Nature of Matter

Matter is composed of extremely small particles. Based on the arrangement of these particles, Matter is mainly divided into three types and they are solids, liquids and gases. These are also called physical states of Matter. This classification is also based on differences in certain physical properties, namely mass, volume, shape, rigidity, density, and arrangement of particles. There are two more states of Matter, namely, plasma and Bose-Einstein Condensate.

Physical Nature of Matter: Classification of Matter

The three states of matter arise due to the differences in interparticle distances, differences in interparticle forces of attraction and differences in kinetic energies of the constituent particles. For example:

1. Sugar, sand, iron, wood, rocks, minerals and ice are solids,
2. Water, milk, oil, kerosene, petrol and alcohol are liquids, and
3. Air, oxygen, hydrogen, carbon dioxide and steam are gases.

Solids, liquids and gases are called the three states of Matter. In other words, Matter exists in three physical states: solid, liquid and gas. The solids, liquids and gaseous forms of Matter have different properties. The characteristic properties of solids, liquids and gases are given below.

These properties can be used to distinguish between the three states of matter: solid, liquid and gas. Let us start with the properties of solids.

Physical Nature of Matter: The Solid-State

Generally, all solids have a definite shape, distinct boundaries and fixed volumes that have negligible compressibility. Solids tend to maintain their shape when subjected to outside force. This shows that they are rigid. However, solids may break under force. Let us study the characteristics of solids in detail.

1. Solids Have a Fixed Shape

 Solids generally have a fixed shape. They do not change their shape even when put in different containers. For example, blue crystals of copper sulphate have needle-like shapes, which they retain whether kept in a beaker or a china dish or placed on the palm of our hand.

Some solids can change their shape under force but retain the same when the applied force is removed.

A rubber band can be stretched by applying force. However, when the stress or the force is removed, the rubber band regain its original shape. Such solids are known as elastics. In case of excessive force is applied, the elastic my break.

2. Solids Have Fixed Volume

 A solid has fixed volume because the interparticle spaces between its particles are fixed.

3. Solids Cannot be Compressed

It is difficult to compress a solid even on applying pressure. This is because the solids particles are so closely packed that they either do not come closer or do so when very high pressure is applied. For example, we cannot press a piece of stone by applying pressure with our hands. On the other hand, a sponge made from rubber material can be easily compressed. We know that the sponge has very small in size holes throughout the body. So, when the pressure has applied, the air from the hole is expelled out, and the sponge gets compressed.

4. Solids Have High Density

 The density of solid may be defined as mass occupied by a solid per unit volume. Since the constituent particles in the solids are so closely packed, the density will be maximum in the solid-state of a substance. Thus, the closer to the constituent particles, the greater will be the density.

5. Solids Have Negligible Kinetic energy of the Particle

 The kinetic energy deals with the movement of the particles from one place to another. Since the constituent particles in the solids are so closely packed, they have negligible kinetic energy. Hence the solids do not flow.

6. Solids do not Have the Property of Diffusion

 Since the solids have negligible kinetic energy of the particles, there is hardly any diffusion due to the absence of vacant spaces between the constituent particles.

7. Solids do not Fill the Container Completely

A solid does not fill its container completely because its particles are held tightly by strong interparticle forces and cannot leave their positions to fill the container.

8. Solids do not Flow

A solid does not flow because its particles are held very strongly and cannot leave their fixed positions.

Examples of solids: Stones, wood, metals like iron, copper, nickel, etc.

Physical Nature of Matter: The Liquid State

We have seen that rigidity is maximum in the solid-state, and Fluidity or particle motion is negligible. In the liquid state of a substance, both these characters are different. Liquid state in the Physical Nature of Matter is less rigid than the solids, and the molecular motion is also comparatively more. Both these characteristics in the liquid state are because of the presence of weaker interparticle forces. The important characteristics of the liquid state of a substance are here.

1. Liquid Does not Have a Fixed Shape

Liquid does not have a fixed shape and takes up the shape of any container in which these are put. This is because the interparticle forces are not very strong, and the particles present in one layer can slide over the other layer quite easily. As a result, a liquid takes up the shape of the container in which it is kept.

2. Liquids Have a Fixed Volume

Since the interparticle forces between the liquid particles are very strong, the pressure applied cannot overcome these forces. Therefore, liquid keep their volume.

3. Liquids Cannot be Compressed Much

This is because their particles are still close together and process very small spaces between them. 

4. Liquids Have Fluidity and not Rigidity

Unlike solids, the liquids have Fluidity and not rigidity; that is, they tend to flow. This is due to lesser interparticle or intermolecular forces present in the liquid state compared to the solid-state. However, the liquids differ in their relative Fluidity. For example, water flows faster than honey because, in honey, the particles are heavier and more closely packed.

5. Liquids Have a Lesser Density than Solids

As compared to solids, liquids are generally light. This is on account of a greater number of interparticle spaces in the liquid state than the solid-state of the same substance. But there are certain exceptions also. Ice floats over water. Both are chemically the same and are made from \({{\rm{H}}_{\rm{2}}}{\rm{O}}\) molecules. The structure of ice is more porous as compared to that of water. Therefore, for a given mass, volume of ice is more than water, and its density is comparatively less. As a result, ice floats over water.

The kinetic energy of the particles in the liquid state is more than in the solid state: The particles in a liquid state are less closely packed compared to the solid-state. As a result, the interparticle forces are weaker. Therefore, the kinetic energy of the particles in the liquid state of a substance is more than in the solid-state. It further increases with the rise in temperature.

6. Particles in the Liquid State can Easily Diffuse

Due to lesser interparticle forces of attraction, the particles in a liquid state can diffuse more readily than the solid-state of a substance. This also helps in intermixing certain liquids. For example, water and alcohol are both liquids and can easily mix to form a liquid mixture or a solution.

Particles of water can easily move into the vacant spaces present in alcohol and vice versa. In addition to these particles of solids and gases can also diffuse into the liquids. That is how both of them dissolve in liquids.

Physical Nature of Matter: The Gaseous State

Out of the three states in the Physical Nature of Matter, the interparticle spaces are the maximum in the gaseous state. The interparticle forces hold the different particles in the gaseous state together at the minimum. As a result, rigidity is the minimum while Fluidity is the maximum. The important properties of this state of Matter are listed. 

1. Gases do not Have a Fixed Shape

Gases do not have any shape of their own. They acquire the shape of the container in which they are filled or kept.

2. Gases Have Maximum Fluidity and Least Rigidity

Since the interparticle spaces are the maximum in the gaseous state, the attractive forces are the least. As a result, the Fluidity is very large while rigidity is negligible.

3. Gases do not have fixed volume and are Highly Compressible

Since the interparticle distance in the gaseous state are very large, they can be changed by altering the pressure. Thus, a gas can be compressed to a large extent by applying pressure. This means that a change in pressure can bring a change in volume, or we can say that gases do not have fixed volume.  

4. Gases are Generally very Light

As compared to the solids and liquids, the gases are generally very light. The interparticle spaces are large. As a result, the particles in a gas are far separated, and the volume of a given mass of a gas is quite large. The density of the gas is very small, and the gases are, therefore, light.

5. The Kinetic Energy of the Particles in the Gaseous State is Very High

Among the three states of Matter, the kinetic energy of the particles is the maximum in the gaseous state, and the interparticle forces are very weak. As a result, the particles or the molecules of a gas can move quitely from one place to the other. This means that their translatory motion is large and kinetic energy is quite high. It can further increase when the temperature of the gas is increased.

6. Gases Exert Pressure

The pressure of a gas is because of the hits that its particles record on the walls of the container. Since particles in a gas have high kinetic energy, they strike the walls of the container with force. As a result, they exert pressure. Please note that the greater the number of hits recorded per unit area of the container’s wall, the pressure of the gas.

7. Gases Diffuse very Rapidly

Since the interparticle spaces are very large and interparticle forces are quite weak, the particles of one gas can readily move into the empty spaces of another gas. That is why the diffusion is maximum among the gases. For example, the smell of food, particularly fish being cooked in the kitchen, spreads in the lobby and even in different rooms because of diffusion. The food particles with specific smells diffuse into the air, and as a result, their smell can be felt even from a distance. Similarly, the fragrance of a burning incense stick spreads all around due to the diffusion of the smoke released from the incense stick into the air.

8. A Gas Kept in a Container Fills it Completely

That is rather surprising because the actual volume of the gas molecules is very small as compared to the intermolecular space. However, the molecules or particles of the gas move at a brisk speed and move throughout the container in no time. Examples: Air is a common example of a gaseous state. It is a mixture of several gases like nitrogen, oxygen, carbon dioxide, inert gases, etc.

Summary: Physical Nature of Matter

When we look at the Physical Nature of Matter around us, we find it in three forms. These are solid, liquid and gas. All human beings are outwardly solids. The water which we drink is a liquid, while the air we breathe in represents a gas. The three states of matter that we have mentioned are because of the interparticle spaces present in different kinds of Matter. This article learned about solids, liquids and gases and their properties. This, in brief, is the physical nature of matter found in the universe.

FAQs on Physical Nature of Matter

The commonly asked doubts on the physical nature of matter are answered here:

Learn Classification of Matter

We hope this article on the Physical Nature of Matter is helpful to you. If you have any queries on this page or in general about Matters physical nature, ping us through the comment box below and we will get back to you as soon as possible.