Static Electricity
Static Electricity occurs in
nature
Electricity
Form of energy and can be
converted to other forms of energy
 Take electricity for granted –
where does it come from?
 Discovered by a Greek philosopher
600BC.
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Objects like a plastic biro, a polythene
rod, or a perspex rod etc.. become
charged when rubbed with a woollen
cloth or other materials.
They can then attract small pieces of paper.
The rubbed materials are charged with
STATIC ELECTRICITY.
Experiment: Demonstrate the production of
static elecricity by friction
Method: 1. Rub a plastic
biro in your hair or your
jumper. 2. Hold it near
some small pieces of
paper
Result & conclusion: The
paper is attracted to
the biro due to staic
electricity on the plastic
biro
“Static electricity involves electric charges
that collect in one place and remain
stationary.”
STATIC ELECTRICITY is electricity that does not
move. It is a build-up of electric charge and can be
produced by friction
Charging by friction (rubbing)
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Bodies become charged by the
gain or loss of electrons a body is
+vely charged if it loses
electrons. A body is –vely
charged if it gains electrons.
The charge that moves is the negative
charge, i.e. the electron which is the
smaller and freer particle in the atom
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If a polythene rod is rubbed with a
woollen cloth, a transfer of electrons
takes place.
Friction (rubbing) causes some of the
outer electrons of the wool to escape.
These get transferred to the polythene
rod.
The rod has now gained electrons and is
negatively charged.
The wool has lost electrons. It now has
more protons than electrons and is
positively charged.
Charging rods positively &
negatively
+
+
+
+
+
+
+
+
+
Friction caused by
rubbing the polythene
rod with the cloth
removes electrons from
the cloth giving it a
negative charge as
electrons are negative
Wool
Lost electrons
Now + vely charged
Polythene Rod
Gained electrons
Now – vely charged
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A perspex rod is now rubbed against the
woollen cloth. The energy produced by
the friction sets some of the electrons
free.
These electrons are transferred to the
wool cloth.
The perspex rod ends up being positively
charged as it has lost electrons.
The wool cloth ends up being negatively
charged as it has gained electrons
Charging rods positively &
negatively
-
-
-
-
-
-
-
-
-
Friction caused by
rubbing the perspex rod
with the cloth removes
electrons from the rod
giving the rod a positive
charge and the cloth a
negative charge
Wool
Gained electrons
Now - vely charged
Perspex Rod
Lost electrons
Now + vely charged
Like Charges repel each other
Unlike charges attract.
Charged bodies
are said to
have static
electricity
Experiment: Show that like
charges repel
Method: 1. Suspend a negatively charged
polythene rod from a retort stand using
some thread. 2. Bring another negatively
charged polythene rod near it.
Result & conclusion: The suspended rd will
move away. Therefore, like charges
repel.
Experiment: Show that unlike
charges attract
Method: 1. Suspend a negatively charged
polythene rod from a retort stand using
some thread. 2. Bring a positive Perspex
rod close to the negative rod.
Result & conclusion: The rods will be seen
to attract. Therefore, unlike chages
attract.
Earthing
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As stated earlier, STATIC ELECTRICITY
is due to electric charges that remain at
rest on an object. These charges cannot
move.
This is because the material on which they
stand are INSULATORS.
“Insulators are substances which do not
allow electric charge to flow through them
easily.”
Examples of insulators: polythene and
perspex rods, glass, plastic, rubber.
Insulators Substances like plastic and rubber
are electrical insulators. This means that they don’t
allow charges to flow through them easily.
A conductor is a substance that allows
electric charge to flow through it freely
eg. metals.
Earthing
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A plastic rod is a good insulator, it can build
up and store quite a large amount of electric
charge.
This charge will remain on the insulator for a
long time. It has no route to go away.
However if a conductor touches the charged
plastic rod, things change.
The conductor becomes the escape route for
the build up charge.
An escape route for this electricity is called
the earth connection.
Charge moves from an object where there is a
surplus of charge to a neutral object like the
earth through a conductor.
“Earthing means connecting an object to the
earth using a conductor so that the object
loses its charge to the earth.”
While an object is earthed a
charge cannot build up in it.
Earthing
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We say an object has been “earthed” when an
object has lost its charge to the earth.
Person getting shock from touching wire, door
handle (metal).
By walking on nylon carpet with rubber soled
shoes, you can easily build up static charge on
your body. this static electricity has no easy
way to flow to the earth unless you touch
something made of metal. You feel a shock as
the charge jumps to the metal and flows away
to the earth.
The earth acts as a sink for charge
Other examples of static
electricity
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Lightning is caused by
static electricity building
up in the clouds.
The amount of charge
builds up until eventually
the cloud earths itself by
sparking to the ground or
to a nearby cloud.