Chapter 1 – Matter in our surrounding
Class 9th Notes Science
Matter:
Anything that occupies space and has mass is called
matter.
It exists in the form of five basic elements, the Panch
tatva – air, earth, fire , sky and water.
For example: Chair, bed, river, mountain, dog, tree,
building, etc.
Characteristics of matter:
Matter is made up of small particles called atoms.
These particles are too small to be observed with naked
eye.
These particles are constantly moving constantly.
These particles have spaces between them.
Particles of matter attract each other because of the force
of attraction.
Diffusion:
Particles of matter intermix on their own with each other.
They do so by getting into the spaces between the
particles. This intermixing of particles of two different
types of matter on their own is called diffusion.
Applications of Diffusion:
Dissolving a solid in a liquid:
When a crystal of potassium permanganate is placed in a
beaker of water, the water slowly turns purple on its
own, even without stirring.
Both potassium permanganate crystal and water are
made up of tiny particles.
, When the potassium permanganate crystal is put in
water, the purple colored particles of potassium
permanganate spread throughout water making the
whole water look purple.
Actually, on dissolving, the particles of potassium
permanganate get into the spaces between the particles
of water.
This shows that the particles have spaces between them
and are continuously moving on their own.
Mixing of two gases:
Fragrance of an incense stick (agarbatti) lightened in one
corner of a room, spreads in the whole room quickly.
The particles of gases (or vapours) produced by burning
the incense stick move rapidly in all directions and mix
with the moving particles of air in the room
This also shows that the partices of matter are constantly
moving.
Brownian motion of particles (By Robert Brown):
The random or zig-zag movement of microscopic particles
in a fluid, as a result of continuous bombardment from
molecules of the surrounding medium, is known as
Brownian motion.
For example, dust moves randomly because the random
moving particles of air collide with dust particles.
Basis of Classification of Matter:
Based upon particle arrangement
Based upon energy of particles
Based upon distance between particles
Three States of Matter:
Class 9th Notes Science
Matter:
Anything that occupies space and has mass is called
matter.
It exists in the form of five basic elements, the Panch
tatva – air, earth, fire , sky and water.
For example: Chair, bed, river, mountain, dog, tree,
building, etc.
Characteristics of matter:
Matter is made up of small particles called atoms.
These particles are too small to be observed with naked
eye.
These particles are constantly moving constantly.
These particles have spaces between them.
Particles of matter attract each other because of the force
of attraction.
Diffusion:
Particles of matter intermix on their own with each other.
They do so by getting into the spaces between the
particles. This intermixing of particles of two different
types of matter on their own is called diffusion.
Applications of Diffusion:
Dissolving a solid in a liquid:
When a crystal of potassium permanganate is placed in a
beaker of water, the water slowly turns purple on its
own, even without stirring.
Both potassium permanganate crystal and water are
made up of tiny particles.
, When the potassium permanganate crystal is put in
water, the purple colored particles of potassium
permanganate spread throughout water making the
whole water look purple.
Actually, on dissolving, the particles of potassium
permanganate get into the spaces between the particles
of water.
This shows that the particles have spaces between them
and are continuously moving on their own.
Mixing of two gases:
Fragrance of an incense stick (agarbatti) lightened in one
corner of a room, spreads in the whole room quickly.
The particles of gases (or vapours) produced by burning
the incense stick move rapidly in all directions and mix
with the moving particles of air in the room
This also shows that the partices of matter are constantly
moving.
Brownian motion of particles (By Robert Brown):
The random or zig-zag movement of microscopic particles
in a fluid, as a result of continuous bombardment from
molecules of the surrounding medium, is known as
Brownian motion.
For example, dust moves randomly because the random
moving particles of air collide with dust particles.
Basis of Classification of Matter:
Based upon particle arrangement
Based upon energy of particles
Based upon distance between particles
Three States of Matter:
