شرح منهج العلوم كامل 2009 بالانجليزي

[ولاء حمدان]

Natural and artificial sources of energy

Sources of energy:
Sources of energy are divided into:
a- Natural sources:
Such as, Sun - wind - waterfalls and fuel.
b- Aritifical (man-made) sources:
Such as, Electric power stations - dams and reservoirs.

First: Natural sources of energy:
A- The sun:
The sun is the main source of energy on the earth because:
1- The sun is responsible for photosynthesis process.
2- The sun is responsible for evaporation of water to form clouds.
3- The sun is the main reason for wind movement that carries clouds to the places when rain falls.

Uses of solar energy:
1- Heating water by solar heaters.
2- Generating electricity needed for satellites and space ships.
3- Desalination of sea water by evaporation and condensation.

B- The Wind:
It is used in:
1- Moving sail boats.
2- Generating electricity by using wind mills.

C- The waterfalls:
They are used in generating electricity by using turbines.

D- The Fuel:


Fuel: It is a substance that can burn and give heat.
Kinds of Fuel:
1- Solid Fuel:
Such as, Wood - cotton straw - maize straw and coal.
2- Liquid Fuel:
Such as Kerosene - gasoline and diesel oil.
3- Gaseous Fuel:
Such as: Natural gas and butagas.

Second: Artificial sources of energy:
Electricity is the most important artificial sources of energy used by man and we can get electricity by different sources such as:
1- Electric power stations.
2- Dams and reservoirs.