Hi I read that in an encyclopedia but I don't understand it. "Because the surface of the material is now electrically charged, either negatively or positively, any contact with an uncharged conductive object or with an object having substantially different charge may cause an electrical discharge of the built-up static electricity; a spark. A person simply walking across a carpet may build up a charge of many thousands of volts, enough to cause a spark one centimeter long or more. This type of discharge is usually harmless because the energy ((V2 * C)/2) of the spark is very small, being typically several tens of micro joules in cold dry weather, and much less than that in damp conditions." THE RED PART iS confusing to me. How come one can creat thousands of volts by rubbing their feet on a carpet while walking? And if that's true the energy is not small at all... E = (V^2xC)/2.... if u have 5000 volts... ?/// PLEASE EXPLAIN ME!!!