Static charge builds up during refueling of aircraft and vehicles due to friction between the fuel and metal surfaces. This charge separation can cause sparks that ignite fuel if the voltage becomes high enough. To prevent fires, aircraft are connected to earth before refueling and vehicle fuel pipes are connected to the metal body to spread out any charge build up. Some applications of static electricity include defibrillators, photocopiers, laser printers, and spray painting. Defibrillators use static charge to contract the heart muscle. Electrostatic precipitators remove dust from smokestacks using charged plates. Spray painting guns use static charge to evenly disperse paint onto an oppositely charged surface.

1. Dangers of Static Charge Electrostatic charge is dangerous when it
causes lightning and sparks that can ignite fuel When an aircraft is being
refuelled with kerosene (paraffin) and when a car is being refuelled with petrol
friction forces cause charge separation Charge separation result in the metal
frame of an aircraft gaining an opposite charge to the fuel This could result in a
build-up of static charge on the metal frame of the aircraft or metal sleeve of the
car refuelling pipe]if the voltage became high enough to cause a spark to earth, it
could ignite the fuel To prevent this, the framework of an aircraft is connected to
earth before refuelling and the pipe leading to the petrol tank in a car is
connected to the body of the car so that the charge can spread out, preventing
the build-up of charge in a small area
Uses of Electrostatics Some uses of static electricity include:
Defibrillators Photocopiers Laser printers Removing dust/soot from smoke
chimneys Spray painting A defibrillator has two charged paddles. These are used
to pass a charge through the patient to make the heart contract. The operator has
to be careful not to be shocked. Good electrical contact is necessary between the
patient and the paddles Electrostatic dust precipitators are used in the chimneys
of coal-burning power stations. They have metal plates/grids connected to high
voltage. Dust particles are attracted to the plates/grids. When the dust particles
are large enough, they fall down the chimneys In spray painting the gun charged.
The paint particles are repelled to produce a fine spray. The object to be painted
is charged opposite to the paint. Attraction between the object and the paint
ensures an even coat of paint. There is less waste in spray painting