Particle Nature of Matter

Particle Nature of Matter: Matter is everything in the universe that has mass and takes up space. Hence, Matter is a generic term that refers to everything around us. Solids, liquids, and gases are the three major classifications of Matter. For ages, the smallest building block of Matter was presumed to be Atoms, as the Atoms have the same chemical nature as Matter’s observable form.

Physical Matter is made up of particles. Through the experiments on diffusion and Brownian Motion, the evidence for the existence of particles in Matter and their motion occurs. Continue reading the article to know more regarding the particle nature of Matter.

Characteristics of Particle Nature of Matter

The following are the characteristics of the particle nature of Matter:

As atoms and molecules are tiny, discrete particles, they can only be discussed at the microscopic level. This can be understood through experiments on diffusion and Brownian Motion.
Particles always attract each other: The molecules in solids have no intermolecular space as they are closely bonded by a strong force of attraction; this force is comparably weaker in liquid and gas.
- There are several forces of attraction between Matter particles that hold them together.
- Cohesion is the term used to describe the force of attraction between particles of the same substance.
- When a piece of chalk, a cube of ice, and an iron nail are hit with a hammer, the chalk is easily broken into smaller pieces while the ice cube needs more energy to shatter, and the iron nail remains intact even when hit with a lot of force.
- This demonstrates that the force of attraction between the chalk particles is very modest, the force between the ice particles is slightly stronger, and the force between the iron nail particles is quite high.
All particles are continuously in motion. When the particles are heated, their speed changes and they begin to move quickly. This can be understood through experiments on diffusion and Brownian Motion.
There is space between the particles of Matter. When sugar is dissolved into water, the sugar crystals separate into very fine particles. These particles of sugar occupy the spaces between the various particles of water. Hence, there is no change in the volume of water.
The only units used to measure Matter particles are the micrometre, nanometer, and picometer.

Particles in Matter: Evidence

Evidence of the existence of particles in Matter may be found in experiments on diffusion or mixing different substances on their own, as well as in Brownian Motion. It is simpler to explain what occurs in various experiments if we believe that Matter is composed of small particles in motion.

Without the idea of particles, things become very hard to define. Discussing various experiments can only be explained by understanding that everything is made up of small particles that are always moving, such as solid dissolving in liquid, mixing of two gases, and movement of pollen grains in water.

Diffusion

Students can go through the below diffusion experiments to understand the existence of particles of Matter:

Dissolving a Solid in a Liquid

Let us look at the following ways to dissolve a solid in a liquid:

When a potassium permanganate crystal is placed in a water beaker, the water slowly turns purple on its own, without stirring.
The tiny particles are made up of both potassium permanganate crystals and water.
The particles separate each other when the potassium permanganate crystal is put in water.
These purple-coloured potassium permanganate particles spread throughout the water turning the water completely purple.
Actually, on dissolving, the particles of potassium permanganate get into the spaces between the particles of water.
So it is concluded that the particles are moving or they are in motion.

Mixing of Two Gases

Let us look at the ways of mixing of two gases:

Air is colourless.
Bromine vapour is red-brown in colour and is heavier than air.
On a gas jar of bromine vapour, a gas jar containing air is placed upside down.
Students can notice that the red-brown vapours of bromine from the lower gas jar begin to spread up into the air in the upper gas jar.
A few moments later, the gas jar containing air turns completely red-brown in colour.
Both air and bromine vapours are made of tiny moving particles. Hence, the moving particles of bromine collide with each other and bounce about in all directions, thus they get mixed uniformly.

Conclusion

The process of diffusion gives us the following conclusions regarding the nature of matter:

Matter is made up of tiny particles.
The particles of Matter constantly move around.

Brownian Motion

Students can go through the below Brownian Motion experiment to understand the existence of particles of matter:

Robert Brown provided the best evidence for the existence and movement of particles in liquids in 1827.
Robert Brown suspended extremely small pollen grains in the water.
It was discovered that the pollen grains moved rapidly in a very irregular way throughout the water.
Water is made up of tiny particles which move very fast.
- The pollen grains move on towards the surface of the water as they are constantly being hit by the rapid moving particles of water.
The zig-zag movement of small particles suspended in the liquid (or gas) is known as Brownian Motion.

Conclusion

The process of Brownian Motion gives us the following conclusions regarding the nature of Matter: