PowerPoint file for Electricity Presentation

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1 Νοε 2013 (πριν από 3 χρόνια και 10 μήνες)

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WOW !

Electricity


David Mowbray

My talk


What is electricity and how do we
make it?


Conductors


transport electricity
to where it is needed


Insulators


stops electricity going
where it shouldn’t go


Super semiconductors

How do we measure the strength
of electricity

1 ½ Volts or 9 Volts

Batteries

Electricity in the

House 240 Volts

-

The Volt

Trams 750 Volts

Lightning more than one
million volts

Electricity carried
between cities
415,000 Volts

What is electricity?


The movement of tiny tiny particles
called electrons


Everything contains electrons


When they move we have electricity

How big are electrons?


How many electrons in a 10cm length of
wire?



100,000,000,000,000,000,000


One hundred million million
million

or one hundred billion billion

Electrons are very very small

How do we make
electricity?

Need something to push
the electrons along the
wire

We can use a battery

But will soon run out
of energy

Electrons

Light bulb

Magnet

A generator

Electrons

Light bulb

Magnet

Magnet has to move to make electricity

The inventor of the generator

Michael Faraday 1791
-
1867

Generator invented in 1831

Generators in a power station

Electricity can be dangerous


how can we
transport it safely to where we want it
and stop it from going where it might
cause danger?

Materials that allow electricity to
flow through them?

Materials through which electricity
can’t flow

Conductors

Insulators

Which materials

are good conductors
and which are
insulators?

Time to experiment!

Conductors and insulators


Conductors are usually metals (but
water and carbon also conduct
electricity)


Examples of insulators include plastics,
wood, glass

Do people conduct
electricity?

Skin is rough

Light pressure


only a few parts of the skin touch the
metal

metal

Wet skin

metal


The water helps the electricity flow
between the skin and the metal

People + electricity +
water = danger!!

OW !

Electricity makes us work

The electric eel



Can produce 600V

The electric ray

Where in the
home are there
people and water?

Must use different switches in
a bathroom

Not these

These

Need to be very careful what
electrical items we use in
bathrooms

None of these in bathrooms

Safety


Never touch electric appliances or
switches with wet hands!



If we get a shock we will not work
properly any more!



When we do experiments we use
small batteries NOT mains
electricity!

Semiconductors
have lots of uses

Semiconductors


what do they
do?

Look at the lump on top of the
lamp

A semiconductor

When it gets
dark the
semiconductor
switches the
street light on

The end


Electricity is the movement of very tiny
particles called electrons


Need some thing to push electrons round
a circuit


a generator


Need materials to transport electricity


conductors


Need material to stop electricity
escaping


insulators


Semiconductors have many unusual but
interesting properties