Re: How can I reduce or get rid of static electricity in my dorm room?

Static electricity is generated whenever two surfaces are placed in contact and then separated. This method of generating static electricity is referred to as "triboelectric charging" or the generation of electricity by contact and separation. A good discussion concerning the generation of electrostatic charge can be found at http://www.midwestesd.org/fundes d1.html. Basically, some electrons will collect on one surface and be pulled off the other surface as two materials are separated.

The same reference provides a table showing the "Triboelectric Series" indicating the relative amount of positive or negative charge generated by contact with a particular material. On the positive end of the series is rabbit fur, glass, and human hair. On the negative end of the series is Teflon and silicone. This Triboelectric Series implies that if you rub rabbit fur on a sheet of Teflon, the Teflon will tend to pick up negative charges (excess electrons), while the rabbit fur will give up electrons, becoming positively charged.

Whenever a charge builds up on surfaces, the difference in electrical potential between the two surfaces is measured in volts. If, in the case of our example, the negative charges on the Teflon surface can find an electrically conductive path to the positive charges on the rabbit fur, then the excess electrons will travel back to the rabbit fur. Often times the voltage may be high enough that it will ionize nearby air molecules, producing a visible spark, accompanied by the familiar crackling sound characteristic of a static discharge. Such static discharges are simply miniature lightning bolts. The process of ElectroStatic Discharge is often referred to as ESD and there are a large number of web sites and journals devoted to ESD control. The bed frame and desk provide an electrically conducting path for the static charges to neutralize themselves, and you feel the effects of this neutralization.

The process of walking across a carpeted room can generate several thousand volts. Sliding across a chair can likewise generate very high voltages. You are right to be concerned about the effects of static charges on modern electronics. The CMOS circuitry of a typical integrated circuit or memory can be destroyed by 50 or 60 volts. A Giant Magnetoresistive (GMR) Head used in some computer hard drives can be destroyed by 5 to 10 volts for a period of 10 nanoseconds (see http://www.esdjour nal.com/techpapr/steinman/ionbal.htm for a further discussion).

People who build electronic devices generally try to incorporate circuitry and controls to protect their equipment against the effects of ESD. However, when you are talking about potentials of thousands and tens of thousands of volts, you can see that the manufacturers have their work cut out for them. A couple of years ago, I just happened to touch the key lock on the front of my computer after walking across the floor. The resulting spark destroyed my motherboard, while if I had touched the case there would have been no problem.

There are two factors involved in controlling static electricity. The first is reducing the production of large static charges by carefully choosing materials. The second is increasing the rate of static dissipation.

If you look over the triboelectric series, choosing clothing of cotton would seem to generated lower static charges than using nylon, wool, and polyester. Likewise, leather soled shows tend to generate less static than some of the man-made polymers. Of course, since you live in a dorm room, you probably have little control over your floor coverings.

Static dissipation is the process of bleeding off the static charges before they have a chance to build to a high enough level to damage your equipment. Niels Jonassen, who worked for 40 years at the Technical University of Denmark and refers to himself as "Mr. Static", provides a great discussion of the various methods of controlling static at: http://www.ce- mag.com/archive/01/07/mrstatic.html

From a practical standpoint, there are two methods that you have available to increase the rate of static dissipation. The first is to increase surface conductance. Surface conductance of insulators is usually related to the amount of moisture on surfaces, since the moisture conducts electricity. Relative humidity plays a large effect in surface conductance. When relative humidity is 60% or above, you generally cannot generate a noticeable spark by walking across the floor. In fact, most people who experiment with static electricity have real problems in high humidity environments.

During winter, the relative humidity inside a heated space tends to drop because moisture in the air is condensed or frozen out of the outside air which, of course, makes its way inside your room. It is quite common for the humidity in the room air to drop to 15% or so, even if it is snowing outside. Therefore, surfaces that do not generate large static charges in the humid summer become much more effective at generating static in the cold winter weather. You can find a chart showing the change in surface resistivity of paper as a function of relative humidity at: http://www.ece.ro chester.edu/~jones/demos/humidity.html

Antistatic sprays attempt to reduce static generally by attracting a layer of moisture which acts as a conductive film. It is likely that dirt or carpet cleaning residue can also help attract moisture and thus reduce the build-up of static. Everyone who has brushed really clean long hair in a low humidity environment knows how easy it is to generate static charges, producing that "fly-away" look. So, "conditioner" is added in the final rinse to add a conductive surface to the hair, helping to dissipate the static charges. Maybe your carpet could benefit from a bit of diluted hair conditioner in a spray bottle.

The other potential method of neutralizing static charges is by using a device such as an air ionizer. A typical air ionizer consists of a high voltage supply that produces a corona discharge, and a fan. Air molecules are alternately given a positive and a negative electrical charge by an ionizer. The charged ions are attracted to charged surfaces with the opposite charge. When the ions come into contact with the charged surface, the charge is neutralized. Ionizers are commonly used in electronics manufacturing environments, less commonly in a residential environment.

So, with all that in mind, probably the cheapest and simplest method of reducing static in a dorm room may to buy yourself a cheap humidifier, and don't clean your carpets too often. It may help you breath easier, too (unless you increase the humidity up to the level that you encourage mold growth-but that is an entirely different issue).