When the charges are separated, it is static electricity. “Electricity is present in all matter in the form of electrons and protons. Any device that develops and maintains a voltage can be considered a voltage source. To accomplish this, the voltage source must remove electrons from one point and transfer electrons to a second point. ” (Petruzella, 2001. ) One type of electricity is static electricity. The term static means standing still which makes static electricity an electric charge that is at rest.
Static electricity is defined as “an accumulation of electric charge on an insulated body. ” (Free Dictionary) In other words, it is a charge that is created when two objects that are not good electrical conductors are rubbed together, and electrons from one of the object rub off onto the other object. Some of the results of static electricity may be sparks, shocks, or even materials clinging together. The simplest way to form static electricity is by friction. Friction is simply the rubbing of one object against another.By rubbing two different materials together, “electrons may be forced out of their valence shells in one material and picked up in the shell of the other material. The material that gives up electrons more freely becomes positively charged and the one that gains electrons becomes negatively charged.
” (Petruzella, 2001. ) When the electrons are relocated from one material to another, it is called triboelectric charging. Static electricity is formed much better in areas with low humidity and dry air. With humid air, tiny water molecules can collect on the surface of different materials and prevent the buildup of an electrical charge.Although small amounts of water, such as those developed from humidity, can affect a charge, “extreme turbulence among water drops”, such as in a thunderstorm cloud, can cause static electricity to build up on the water droplets themselves. Benjamin Franklin showed that static electricity is created in a thunderstorm cloud by flying a kite during a storm. He noticed the static electricity by seeing the hairs on the kite stand on end and created an electric spark with a metal key.
There are other ways to produce a static charge other than friction or contact.An object can also be charged by induction. Induction is used to produce a charge of opposite polarity. Inductance is defined in the text as an “electrical property which opposes change in current. ” (Petruzella, 2001. ) An inductor is “a device that generates a counter emf that tends to oppose any change in current through the use of ac current flowing through a coil wire. ” (Petruzella, 2001.
) Charging by induction makes use of the electrostatic field surrounding a charged body in order to charge an object without touching it.If a negatively charged rod is brought close to the sphere on the inductor, the negative charges in the sphere move as far away from the rod as possible. By touching the sphere, it is grounded and allows the electrons to completely leave the sphere. Once you remove your finger, the electrons no longer have a way of returning to the sphere and the rod is then positively charged. Static electrical charge can be produced by a high-voltage direct current source. Many air purifiers use both positively and negatively charged plates to remove tiny dirt particles from the air.This system uses an electrostatic precipitator and oppositely charged grids.
The dirty air moves through the precipitator which gives the dirt particles a positive charge. All of those particles are then attracted to the negatively charged grid and then the air passes through a carbon filter to remove any odors. Static electricity is also used with photography to work a photocopier. An “electrostatically charged drum” attracts toner particles to the image in the original document. The metal drum inside the machine is charged at the eginning of each copy. The system inside the photocopier then puts an image of the document onto the drum. The electric charge goes away wherever light shines on the drum and so only the dark parts of the image are still charged on the metal surface.
The particles of black toner are oppositely charged and then applied to the drum. The charged parts, which contain the image, are attracted to the toner and transferred to the paper and finally attached to the paper with heat. Static electricity can cause materials to attract or repel each other.If you use a hair dryer on your hair and then comb through it or just comb it on a very dry day, the plastic comb will collect negative charges from the hair and leave the hair with an excess amount of positive charges. Since like charges repel, the hair strands will push away from each other causing your hair to stand up or “flyaway. ” Static electricity can also cause a spark to jump from one material to another, like when you touch someone and “shock” them. As you walk across something like a carpet, electrons cling to you.
When you have extra electrons, you then have a negative charge and are attracted to positive charges so once you touch someone else, assuming they have a positive charge, you will feel a tiny shock which is a quick movement of electrons. If there are enough positive electrical charges on one object or material and enough negative charges on another, the attraction may be so great that the electrons will jump to the other object with out the two touching. After a few electrons make the jump, the air begins to heat up and causes more and more electrons to move and the air to get even hotter.This all happens so fast and causes the air to get so hot that it glows for a split second and is known as a spark. The same process occurs with lightning only on a much larger scale. Removing or preventing a static charge can be very simple such as opening a window or using an air humidifier to “increase the moisture content of the air and make the atmosphere more conductive. ” (Wikipedia) Items that are very sensitive to static discharge can be treated with an antistatic agent.
Wikipedia defines an antistatic agent as something that “adds a conducting urface layer which ensures that any excess charge is evenly distributed. ” An example of an antistatic agent is fabric softener or dryer sheets which are used in your laundry to prevent and remove static cling. “Semiconductor devices” which are used in electronics are very sensitive to static charge. These devices are protected using antistatic bags and those who work with these devices ground themselves by wearing conductive antistatic straps to protect their bodies. To test for a charge on an object, you must see how that object affects another object with a known charge.If the two objects repel, that means their charges are alike and if they attract, the charges are opposite. To see if an object is neutral, test it with another neutral object.
Neutral objects do not attract with each other, only with another positive or negative object. “An aluminum-leaf electroscope is a device for detecting the presence of an electric charge and also for determining whether the charge is positive or negative. ” (Petruzella, 2001. ) This device is made up of a flask with an insulating stopper. A metal rod goes through the center of the stopper and a metal knob is fastened to the outside end of the rod.Two very thin pieces of aluminum are attached to the other end of the rod inside the flask. “Normally the positive and negative charges within the electroscope balance each other, leaving it neutral.
When a negatively charged body touches the knob of the electroscope, electrons flow from the charged body into the knob and down to the aluminum leaves. Each leaf then becomes negatively charged. Since like charges repel and both leaves are negative, they will diverge, indicating that the object contained a static charge. ” (Petruzella, 2001. )In conclusion, static electricity is all around us. It may clean our air or be the cause of a terrible hair day but has both positive and negative effects on many daily routines.Work Cited Page Petruzella, Frank.
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