Static electricity facts for kids

Contact with the slide has left this child's hair positively charged so that the individual hairs repel one another. The hair can also be attracted to the negatively charged slide surface.

Lightning, one example of static discharge

Static electricity means the increase of electric charge on the surface of objects. This electric charge remains on an object until it either flows into the ground, or loses its charge quickly by a discharge. Charge exchange can happen in conditions like when different objects are rubbed and separated. A static charge will only remain when one of the surfaces has a high resistance to electrical flow. The effects of static electricity are familiar to most people because they can see, feel and even hear the spark. This spark happens when the excess charge is neutralized. This neutralization occurs when excess charge flows into an electrical conductor (for example a path to ground). Other charge flow occurs when a charged object is near a region with an excess charge of the opposite polarity (positive or negative). The familiar phenomenon of a static 'shock' is caused by the neutralization of charge.

History

In Greek age, Thales found static electricity when he was cleaning his amber. But at that time, they did not pay attention to this and research it. They just knew that rubbing something made a pulling force. Earnest research into static electricity was started in the 17th century, when Otto von Guericke made the first friction generator. And in the 18th century, Coulomb started research into a fixed quantity of static electricity. Benjamin Franklin associated static electricity with storms. In 1832 Michael Faraday published the results of his experiment on the identity of electricities. This report proved that the electricity made by using a magnet, voltaic electricity produced by a battery, and static electricity are all the same. Since Faraday's result, the history of static electricity can be thought as the study of electricity in general.

Charge

Many situations can cause static electricity.

1. Contact makes charge separation:

   Most materials have a unique chemical attraction for electrons. Because of this, rubbing different materials can cause charge separation. The material will have a positive charge if it has a lower attraction for electrons than the other material.Sometimes, by walking across a carpet then touching a metal item(doorknob e.g.) can cause a static electricity shock.

2. Pressure makes charge separation:

   Strong enough pressure make a separation of charge in certain types of materials, like crystals and ceramics molecules.

3. Heat makes charge separation:

   Heating certain materials can give electrons power.By this power electrons break free from atoms.The atoms loosing electrons become a positive charge.

4. Charge makes charge separation:

   A charged object can make a neutral object have charge separation. Charges of the same sign (negative to negative or positive with positive) repel each other, and charges of the opposite sign attract each other. This force makes the part of the neutral object that is near the charged object have opposite charge of the charged object. This force rapidly weakens if the two objects move away from each other. The effect occurs most when the neutral object has a charge which can move freely.

   Static electricity can cause a mild shock.

Removal and prevention

A network card inside an antistatic bag.

An antistatic wrist strap with crocodile clip.

Removing or preventing a buildup of static charge can be as simple as opening a window or using a humidifier, to increase the moisture content of the air, making the atmosphere more conductive. Air ionizers can perform the same task.

Items that are particularly sensitive to static discharge may be treated with the application of an antistatic agent, which adds a conducting surface layer that ensures any excess charge is evenly distributed. Fabric softeners and dryer sheets used in washing machines and clothes dryers are an example of an antistatic agent used to prevent and remove static cling.

Many semiconductor devices used in electronics are particularly sensitive to static discharge. Conductive antistatic bags are commonly used to protect such components. People who work on circuits that contain these devices often ground themselves with a conductive antistatic strap.

In the industrial settings such as paint or flour plants as well as in hospitals, antistatic safety boots are sometimes used to prevent a buildup of static charge due to contact with the floor. These shoes have soles with good conductivity. Anti-static shoes should not be confused with insulating shoes, which provide exactly the opposite benefit  – some protection against serious electric shocks from the mains voltage.

Within medical cable assemblies and lead wires, random triboelectric noise is generated when the various conductors, insulation, and fillers rub against each other as the cable is flexed during movement. Noise generated within a cable is often called handling noise or cable noise, but this type of unwanted signal is more accurately described as triboelectric noise. When measuring low-level signals, noise in cable or wire may present a problem. For example, the noise in an ECG or another medical signal may make accurate diagnosis difficult or even impossible. Keeping triboelectric noise at acceptable levels requires careful material selection, design, and processing as cable material is manufactured.

Discharge

Static discharge is excess charge that is neutralized by a flow of charges from or to the surroundings. Positive charges get electrons from the surroundings, and negative charges lose their electrons to the surroundings.

The feeling of a static electric shock is caused by the stimulation of nerves as the neutralizing current flows through the human body. Due to the presence of much water in the body, the charge is generally not enough to cause a dangerously high current. Lightning is also an example of static discharge. A cloud gets a very huge charge by clashing with other clouds. It gives off the excess charge to the ground. But this huge charge never occurs in the human's surroundings naturally, unless he is struck by the lightning.

Despite the apparently harmless nature of static electricity, there can be significant risks in research, because a large charge can break down the equipment.

Images for kids

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  Styrofoam peanuts clinging to a cat's fur due to static electricity. This effect is also the cause of static cling in clothes.

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  Small hairs standing up after a thunderstorm, as a result of the left over weak static electricity

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  Static electricity is a major hazard when refueling an aircraft.

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  Ozone cracking in natural rubber tubing

See also

In Spanish: Electricidad estática para niños