Introduction

Static electricity is a common phenomenon to experience, particularly in winter.  You walk across a carpeted rug, then touch a door handle and…zap! A little spark stings you as it arcs between your fingers and the metal doorknob.  Or you brush your hair, and find that it starts sticking straight up following the brush as it approaches your head.  This paper addresses the issue of static electricity, what it is, and what its effect is.

Discussion

Because matter is made up of atoms, and atoms have a positively charged nucleus orbited by negatively charged electrons, all of matter has electrical charge associated with it. Normally,  positive charge of the nucleus exactly equals the negative charge of the electrons so the atom  is electrically neutral.  If an atom loses an electron for some reason, the atom becomes positively charged because the nuclear positive charge is larger than the negative charge of the remaining electrons.  If the atom collects an extra electron for some reason, the opposite is true and the negatively charged electrons outnumber the positive charge in the nucleus, resulting in an overall negative charge for the atom (Library of Congress, 2011).

Static electricity happens when electrically charged atoms (either positively or negatively charged) collect on the surface of an object.  That makes the surface slightly positively or negatively charged.  Because those charges simply sit on the surface, and are not part of an electrical current, this is called “static” (i.e., not moving) electricity (Kurtus, 23 January 2009).

To generate a static charge on a surface, typically two different types of materials are rubbed together.  One is a material that tends to shed electrons (and thus develop a positive charge) and a second material that tends to collect electrons (and thus develop a negative charge) (Science Made Simple, 2009).  Building a static charge is easier when the humidity is low—which is why it happens so often in winter—because if there are water molecules on the surface of the materials it’s harder to get the charges to build up (Kurtus, 23 January 2009).  It’s also important to know that it is not friction that causes static electricity to build up.  Instead, it’s the fact that the two materials adhere, and when they are rubbed together, a larger surface area is allowed to adhere, which builds up more charge (How Stuff Works, n.d.).

A Van de Graff generator is a machine that generates a significant amount of static charge—up to millions of volts of electricity.  The generator has a  motor which turns a roller with a belt around it, usually arranged to rotate vertically.  The upper end of the belt loops around another roller and the belt brushes against a metal brush which is attached to an enclosing sphere of metal (usually aluminum or steel).  The rubber belt, brushing constantly against the metal brush generates a static charge which is transferred to the enclosing sphere. That sphere “holds” the charge, allowing very large static electrical charges to accumulate (How Stuff Works, n.d.).

Static electricity is everywhere.  In addition to being common in winter, it also is the basis for lightning as a charge separation between the clouds and the ground.  As with a Van de Graff generator, a lightning bolt can amass thousands of volts of electricity, enough to do serious damage, start fires, or even kill (Wikipedia, 18 May 2011).

Conclusion

Static electricity is a natural phenomenon of everyday life.  It is a common phenomenon in winter, but it’s also common in other seasons, in lightning storms.  It happens when two different materials accumulate a separation of charge, with positive charge building up on one object and negative charge building up on the other.  A Van de Graff generator can be used to develop huge static electrical charges by rubbing a rubber belt against a metal brush connected to a metal sphere which can amass the charge.  Because static electricity is the basis for lightning, it can be destructive as well as awe-inspiring.