static electricity is caused when two insulators rub together causing friction
electrons will be scraped off of one
and on to the other leaving one of
them with a positive charge (as loss of
electrons always makes a positive
charge) and a negative on the other.
Electrically charged objects attract
small neutral objects
like charges repel, opposite charges attract
static electricity can be a nuisance
attracting dust - dust particles
are charged and will be
attracted to anything with the
opposite charge.
Unfortunately many objects
around the house are
insulators that get easily
charged and attract the dust
particles
clothing - when synthetic clothes are
dragged over each other or over
your head electrons get scraped off
leaving static charges on both parts
and that lead to attraction and little
sparks or shocks as the charges
rearrange themselves
shocks from door handles - if you walk on a nylon carpet
wearing shoes with insulating soles, charge builds up on your
body. Then if you touch a metal door handleothe charge flows
via the conductor and you get a little shock
static electricity can be dangerous if it's near any inflammable gases.
dangerous sparks can be prevented by earthing
the object to the ground using a conductor
uses of static electricty
electrostatic paint
sprayers - the spray gun
is charged which charges
up the small drops of
paint. Each paint drop
repels all the others
because they all have the
same charge so it is a
very fine spray. The
object to be painted is
given an opposite
charge. This method
gives you an even coat
with hardly any wastage.
dust precipitators - a wire grid or rods is
put in the chimeny of factories with a
negative charge and hig voltage and.
Smoke particles meet meet them and gain
electrons, becoming positively charged.
They then induce a charge on the earthed
metal plates and are attracted to the metal
plates and form larger, heavier particles
when they stick together, They then fall of
when knocked off by a hammer which falls
to the bottom of the chimney and can be
removed
defibrillators - an electric shock to a stopped
heart can make it start again as your heart is
controlled by tiny little electrical pulses
inside your body.Defibrillators are used in
hospitals to do this. It consists of two
paddles connected to a power supply. They
are paced firmly on the patients chest to get
a good electrical contacts and then is
charged up. Everyone moves away apart
from the operator (holding insulated handles)
so that only the patient gets the shock. The
charge then passes through the paddles to
the patient to make the heart contract.