9th science

Matter In Our Surroundings

Chapter Summary

Anything that has both mass and volume is called matter.

Particles of matter have space between them.

Force of attraction between particles of matter keeps the particles bonded together.

There are three states of matter – solid, liquid and gas.

Matters which have fixed volume and shape are called solids.

Matters which have fixed volume but indefinite shape are called liquids.


Matters which have indefinite shape and volume are called solids.

The process of change of water into vapor is called vaporization.

The temperature at which a liquid boils is called its boiling point.


The change of vapor into water because of decrease in temperature is called condensation.

The change of liquid into solid because of decrease in temperature is called freezing.

The change of solid into liquid due to increase in temperature is known as melting.


Latent heat is the heat released or absorbed by a body during the process without change in temperature of the system.

The process in which a solid changes into vapor without changing into liquid and from vapor changes into solid without changing into liquid is known as sublimation.

The change of liquid into vapor without reaching at its boiling point is called Evaporation.


Factors affecting the Evaporation are; Temperature, Pressure, Surface area, Humidity in air and Wind speed.

The phenomenon of mixing of particles of different substances together is known as diffusion.

Diffusion takes place from higher concentration to lower concentration.