UNIT 4 MATTER
THE PROPERTIES OF MATERIALS
· PHYSICAL PROPERTIES
Hard: Difficult to scratch or cut easily.
Soft: Easy to scratch or cut.
Tough: Difficult to break.
Fragile: Easy to break.
Plastic: Easy to bend.
Elastic: Go back to their shape after we squash or stretch them.
It describes if a material can dissolve in water.
Soluble: Materials that dissolve.
Insoluble: Materials that don´t dissolve.
· THERMAL CONDUCTIVITY
It describes if a material can get very hot.
Thermal Conductors: Materials that can get hot.
Thermal Insulators: Materials that don´t get hot.
THE PROPERTIES OF MATTER
It is the amount of space that matter occupies.
Unit: Cubic centimetres (cm³).
It is the amount of matter in an object.
Unit: Grams and kilograms.
It is the amount of mass that there is in the volume of an object.
To find out the density of an object, we divide its mass by its volume.
CHANGES IN MATTER
· PHYSICAL CHANGES
The composition of the matter doesn´t change. Physical changes can be reversed.Physical changes: shape, place, state and temperature.
· CHEMICAL CHANGES
The composition of the matter changes and new matter is formed.
MIXTURES AND SOLUTIONS
• MIXTURES AND TYPES
When two substances are mixed together they form a mixture.
There are two basic types of mixture: a heterogeneous mixture and a homogeneous mixture,
In a heterogeneous mixture we can see the separate substances ( For example: salad).
In a homogeneous mixture we can´t see the separate substances ( For example: hot chocolate). This is because one sustance dissolves into the other. A homogeneous mixture where one sustance dissolves in another is called solution (hot chocolate). The susbtance that dissolves is called the solute (chocolate powder) and the substance that dissolves it is called the solvent (milk).
• SEPARATING MIXTURES
Filtration: It is used to separate an insoluble solid from a heterogeneous mixture. For example: sand and water.
Evaporation: It is used to separate a soluble solid from a homogeneous solution. For example: salt and water.
Distillation: It is used to separate a liquid from a solution or to separate two liquids. For example: alcohol and water.