Static Electricity

To understand static electricity, one has to know the basics of atoms. An atom has a nucleus consisting of protons and neutrons, and electrons, which move around that core. Protons have positive (+) charge; neutrons are neutral; and electrons have negative (-) charge. Normally an atom has equal number of protons and electrons. In that condition it is without any charge. But sometimes the electrons migrate. This causes a reduction in the negative charge and the atom becomes positive. An atom thus charged is called an 'ion'. Rubbing materials against each other can create the imbalance between protons and electrons.

Electrons cannot pass easily through certain materials that have insulating properties. When such a shield exists, the charge that builds up remains static unless it is grounded or otherwise handled. Sometimes the voltage gradient reaches an intensity that forces the insulator to break down. Lightning is an example of this. (Here, dry air is the insulator between the clouds that sometimes carry static electricity.)

Industry loses billions of dollars annually because of damages caused by static electricity in several ways. This energy can lead to problems in day-to-day life as well. For instance, static electricity may result in malfunctioning of electronic hearing aids. Gasoline safety rules warn against reentering a vehicle while it is self-filling. There have been reported instances of fire erupting because the person coming out of the vehicle touches the nozzle without defusing static electricity. Touching the metal part of the car away from the filling point when the person gets out can avoid this danger.

It is essential to eliminate to the extent possible or control this motionless electric charge to avoid the problems. The first step towards this is to measure and analyze static electricity. Effective instruments are available for this. Next, the appropriate process should be selected and set in motion with the help of experts. Induction in which tinsel is usually used is a simple and effective method. Grounding, where a conductive mat is often employed, is an alternative. Another procedure is to use a static eliminator to neutralize static electricity by ionization.

Static electricity is not always a villain. It is energy that can be harnessed. Industry is also finding uses for it. To give one instance - for the In-Mold Labeling process, static electricity efficiently holds up the labels.

The ability of opposite charges in static electricity is what's used when designing applications for it.

Dust removal: There are some appliances that can eliminate dust from the air, like air purifiers. They use static electricity to alter the charges in the dust particles so that they stick to a plate or filter of the purifier that has an opposite charge as that of the dust (opposite charges attract each other). This effect is also used in industrial smokestacks to reduce the pollution that they generate, although they work in a very large scale, the effect is basically the same as in the home air purifiers.

Photocopy: Copy machines use static to make ink get attracted to the areas where we need the information copied. It uses the charges to apply the ink only in the areas where the paper to be copied is darker (usually this means text or other information) and not where the paper is white, this process is called xerography.

Car painting: To make sure a car's paint is uniform and that it will resist the high speeds and weather to protect the car's metal interior, it is applied with a static charge. The metal body of the car is submerged in a substance that charges it positively, and the paint is charged negatively with the paint sprayer. This process ensures a uniform layer of paint, since when there is enough negative paint in the car the extra will be repelled by the paint already in the car. It also ensures that the paint won't fall off, since the electrical attraction between the paint and the car is stronger than if it was just sprayed.

All of these processes use electronic circuits to generate and control the static charges generated. Many people have wondered if static electricity can be used as a source of power for homes and industries. Despite the extremely high voltages that can be generated with static electricity (tens of thousands of volts, compared that to the 220v or 110v of a common power outlet) the amount current it can generate is very low, from microAmperes to a few miliAmperes and only for very short times.

Storing electricity is so inefficient that power plants will just sell the extra energy at a lower price or let it unused and lost instead of storing it because of the cost and also the amount of energy that can be stored is not significant enough to offset the expenses.