Static Electricity

Many people ask about shocks experienced when they touch the door, filing cabinet, lift, or other metal object.  So where do these tiny bolts of lightening come from?

Static electricity is generated whenever two materials are in contact with each other. All materials are made of electrical charges in the material atoms. In the universe, there are equal amounts of negative electrical charge (electrons) and positive charge (protons). These generally try to stay in balance of equal amounts at every location. 

However, when two materials are in contact, some of the charges redistribute by moving from one material to the other. This leaves an excess of positive charge on one material, and an equal negative charge on the other. When the materials move apart, each takes it's charge with it. One material becomes charged positively, and the other negatively.  

If the materials are able to conduct electricity away, the charges will dissipate and eventually recombine. In this case, static electricity effects may be too small to be noticed. However, if the charges are separated faster than the material can dissipate them, the amount of electrostatic charge builds up. Eventually a high voltage, and the effects of static electricity, may be noticed. 

Does the car produce the static or do we generate it?

Many people experience shocks when they get out of their car. Often they believe that the car is charged - but this is not normally so. When sitting in the car, electrostatic charges are generated on the car seat and the person's body, due to contact and movement between the clothes and the seat. When the person leaves the seat, they take half of this charge with them. As they get out of the vehicle, their body voltages rises due to this charge. When they reach to touch the vehicle door, the electrostatic discharge and shock occurs as their hand approaches the metal door. 

The voltage build-up can often be avoided by holding onto a metal part of the door frame as you leave the seat. This provides a return dissipation path for the charge on your body. If you have forgotten to hold the metal door part as you leave the seat, a shock may often still be avoided by touching the glass window before you touch the metal door. The glass may be conductive enough to dissipate charge, whilst preventing the rapid discharge which is felt as a shock. 

Static and Humidity