All the things in this world are made of matter

Living thing

Non-living thing

All the matter can be split up into tiny units. These units are so small that we cannot even see them. These tiny units

are called molecules.

Experiment of chalk

A piece of chalk is made of matter. Now suppose we want to see what this matter is made of. We will have to break this piece of chalk down into Smaller pieces.A scientist can break down the tiny visible piece of chalk even further till it becomes invisible to eye. These invisible particles are Molecules.

A molecule can be further broken down into still smaller units called atoms.

Dust of chalk

Three forms of matter

Solids

• The molecules are closely packed

• There is not much space between them so they can not move easily

• This keep them a definite shape and volume

• E.g.: Wood, salt, iron

Liquids

• The molecules are not so closely packed

• They have more space between them to move

• So liquid can flow and do not have a definite shape

• E.g.: Oil, water, cold drink, petrol

Gases

• The molecules have lot of space between them

• They can move around more freely

• Do not have definite shape

• E.g.: Oxygen, nitrogen, chlorine, carbon

Experiment

• Ice, water, boiling vapor

Solution

Solute + Solvent = Solution

Experiment

• Potassium permanganate + water = Pink solution

• The solute has filled in the space between the molecules of the liquid.

Miscible liquids

• Some liquids can dissolve in water, they are called Miscible liquids.

Experiment: milk + water= Milk water

Immiscible liquids

• Immiscible liquids are those which do not dissolve in water, such as oil.

Gases in water

• Some gases are dissolve in water.

• Fish and other water animals breath in the oxygen dissolved in water.

Carbon dioxide is dissolved in colas to make them fizzy.