Transcript ELECTRICITY AND MAGNETISM

ELECTRICITY AND MAGNETISM
UNIT 5
Transporting electricity
The energy for generating electricity comes from different sources.
• The generator transforms energy (wind, water…) into
electricity.
• The transformer changes the voltage of the electricity so can
travel long distances.
•The cable transports an electric current from the generator to
the transformer.
• The pylon holds electricity cables off the ground.
•Smaller transformers reduce the voltage in the town and make
the electricity safer for us to use.
• The plug and socket connect a machine to the electricity supply.
STATIC ELECTRICITY
•Static electricity can make when we rub two non-metal objects together.
All objects have electrical charges. They can be positive or negative.
If an object contains more positive charges than negative charges, it has a positive
charge.
If an object contains more negative charges than positive charges, it has a negative
charge.
Objects with opposite electrical charges attract each other.
Objects with the same electrical charge repel each other.
Current electricity
Electric current is the movement of electrical charges.
Electrical insulator doesn’t allow electric current to flow easily through them: wood
rubber, plastic and glass.
Electrical conductor can flow easily electric current: copper, iron, aluminium (metals)
and water.
An electric current can only pass through a circuit that is closed.
ELECTRIC CIRCUIT is usually made up of:
•Generator: supplies the electricity.
•Conductor: lets the electricity flow through the circuit. (metal wires – copper wires)
•Electrical component: transforms electricity into another form of energy. (light bulb –
light energy)
•Switch: opens and closes the electric circuit.
MAGNETISM
Magnetism is the ability to attract metals, iron and mixtures of iron-.
A magnet is an object which can attract certain metals.
• It can be : natural (magnetite) or man-made.
• It can be different shapes and sizes.
•It has two poles: north and south pole.
•The poles are the parts of the magnet which attract metal objects.
•When two magnets touch at the poles:
•If we put the same poles together, the magnets repel each other.
•If we put opposite poles together, the magnets attract each other.
A magnetic field is the area of magnetic force.
We can’t see it. But you can see the effects of it.
Electromagnet is temporary magnets.
An electromagnet is only a magnet when an electrical current
flows through the coil around it.
SOURCES OF ENERGY
Energy sources provide us with the energy that we need to make
electricity
Non-renewable
Renewable
•Uranium
sunlight, wind, water
•Fossil fuels
Biomass
Geothermal
NON RENEWABLE
advantages
disadvantages
Coal
Produces a lot of
energy
It’s nonrenewable and a
pollutant
Oil
Is easy to
transport and
store
Uranium
We have enough
to generate
electricity for
many yaears.
RENEWABLE
advantages
disadvantages
Solar energy
Renewable and
noon-pollutant
Solar panels are
expensive and
can’t work
without bright
sunlight.
Oil spills can
cause ecological
disasters.
Water
Renewable and
noon-pollutant
The construction
of dams destroy
habitats.
Produces
dangerous waste
products and the
nuclear power
stations are
expensive
Wind
Renewable and
noon-pollutant
Sometimes there
no wind and wind
turbines damage
habitats and kill
birds.
Biomass
Renewable and
there’s always
waste
Causes air
pollution.
Geothermal
Renewable and
noon-pollutant
It’s only found in
certain areas.