NS 5: UNIT 8. ENERGY

 

Unit 8: Energy

 

      8.1 Forms of energy.

      8.2 Energy sources.

      8.3 Electricity and magnetism.

 

8.1 Forms of energy.

- Energy allows us to do many things.

- There are six forms of energy: light, chemical, sound, kinetic, electrical and thermal energy.

Ø     Light energy.- Characteristics:

·    It comes from The Sun.

·    It travels very fast at 300.000 Km per second.

·    It always travels in a straight line.

·    It illuminates objects.

Ø     Chemical energy.- Characteristics:

·    It happens when a chemical reaction occurs.

·    Chemical energy is transfomed in kinetic energy.

·    Sources are: batteries and food.

 

Ø     Sound energy.-Characteristics:

·    Sound is a vibration and travels in any direction.

·    Large vibrations are loud sounds and small vibrations are soft sounds.

·    Sound can travel through liquids, solids and gases.

 

 

Ø     Kinetic energy.- Characteristics:

·    It is related to the movement.

·    Examples are a moving car or moving bike.

 

Ø     Electrical energy.- Characteristics:

·    Power machines transforms electrical energy into light, sounds, heat and movement.

·    Electricity is also produced by sunlight, wind, water and biomass.

·    Nuclear power stations are places which create electricity.

 

 

Ø     Thermal energy.- Characteristics:

·    It flows in a warm substance.

·    This flow is called heat.

·    Sources to heat  are: The Sun and fossil fuels such as coal, oil and gass.

 

 

 

8.2 Energy sources.

There are two types of energy sources: renewable and non-renewable energy.

Ø     Renewable energy.- Characteristics:

·    They can be replaced so they will never run out.

·    Examples are: solar, wind, water, biomass and geotermal energy.

 

v     Solar energy: It is used with solar panels and in sunny climates.

 

v     Wind energy: It is used with wind turbines and in windy places.

 

 

v     Water energy: It is used with dams but causes biodiversity loss.

 

v     Biomas energy: It is used with pellets made of organic material but produces air pollution because they are burnt in nuclear power stations.

 

 

v     Geothermal energy: It is used with volcanes and hot springs but it is limited in certain geografic areas.

 

Ø     Non-renewable energy.-

Characteristics:

·    They cannot be replaced so they will run out.

·    Examples are: fossil fuels and uranium.

 

v     Fossil fuels: Examples are: coal, oil and natural gas. They are in the undergrounf for millions of years.

 

v     Uranium: It is a radioactive metal which is used in nuclear power stations. It is dangerous because radioactivity can cause cancer.

8.3 Electricity and magnetism.

Ø    Electricity. Characteristcs:

·    Electricity has electrical charges: positive and negative charges.

·    Opossites attract each other.

·    Materials can be electrical conductor sor electrical insulators.

·    There are two types of electricity: current electricity and static electricity.

 

v    Current electricity: It moves through electrical conductors.

v    Static electricity: It is produced by thunderstorms and electricity doesn´t flow.

 

Ø    Magnetism. Characteristics:

·    A magnet is an object that attracs others. They can be natural or man-made.

·    Magnetism is the ability to attract these metals.

·    Magnets can be positives or negatives. The biggest ones are: the North Pole and the South Pole.