UNIQUE FRIENDS SCHOOLSMeaning of Matter
Matter is anything that has weight (mass) and occupies space. Everything around us is made of matter.
Matter exists in three main states:
Solid
Liquid
Gas
1. Solids
Solids have a definite shape and fixed size. The particles in solids are closely packed together.
Properties of Solids
Have a fixed shape
Have a fixed volume
Cannot flow
Strong and firm
Examples
Stone, book, table, pencil, iron.
2. Liquids
Liquids do not have a fixed shape but have a fixed volume. They take the shape of the container they are poured into.
Properties of Liquids
No definite shape
Fixed volume
Can flow easily
Can be poured
Examples
Water, milk, oil, juice.
3. Gases
Gases have no fixed shape and no fixed volume. They spread to fill any available space.
Properties of Gases
No definite shape
No fixed volume
Spread easily in air
Cannot be seen easily
Examples
Air, oxygen, carbon dioxide, cooking gas.
Changes of State
A change of state happens when matter changes from one form to another due to heat or cooling.
1. Melting
Melting is the change from solid to liquid when heat is added.
Example: Ice changing into water.
2. Freezing
Freezing is the change from liquid to solid when heat is removed.
Example: Water turning into ice.
3. Evaporation
Evaporation is the change from liquid to gas when liquid is heated or exposed to air.
Example: Wet clothes drying in the sun.
4. Condensation
Condensation is the change from gas to liquid when gas cools.
Example: Water droplets forming on a cold bottle.