BOK_FINISH_9a.indd



would like to meet the physicist that could explain that one. The highly energized
body must exhibit an opposite current and electromagnetic field powerful enough
to cause the current to alter its course and to leave the wire filament and arc out
through the air.
A charged atom is called an “ion.” An atom that looses electrons has more
positive charges (protons) than negative charges (electrons), thus it becomes a
positively charged ion. Conversely an atom that gains electrons has more negative
than positive particles, that is if it picks up extra electrons it is a negatively charged
ion. Opposite or different charges (a positive and a negative) will attract, or pull
towards each other, while ions of the same charge will repel. The triboelectric effect
is a type of contact electrification in which certain materials become electrically
charged through friction. The amount of charge generated by the triboelectric
effect depends on the area of contact, the speed of separation (friction), relative
humidity, and other factors. During the summer when the air is more humid, the
water in the air helps electrons move off us more quickly, so we do not build up as
much electrostatic charge.
static electricity is defined as an electrical charge caused by an imbalance of
electrons on the surface of a material. This imbalance of electrons produces an
electric field that can be measured and that can influence other objects at a distance.
Once the charge is created on a material, it becomes an “electrostatic” charge
which may be transferred from the material, creating an electrostatic discharge
event. electrostatic discharge (ESD) is defined as the transfer of charge between
bodies of different electrical potentials. The most spectacular form of ESD is the
spark, which occurs when a strong electric field creates an ionized conductive
channel in air. Electrostatic discharge lightning can cause minor discomfort to
people, severe damage to electronic equipment, and fires and explosions if the air
contains combustible gases or particles.
The best known example of a spark is a lightning strike. The earth is positively
charged and the bottom of a cloud is negatively charged. When the EMF of the
cloud is at a certain threshold, a bolt of lightning occurs. The spark is triggered
when the electric field strength exceeds a certain threshold value in the air, causing
a rapid increase in the number of ions in the air (electrical breakdown), and
these free ions temporarily cause the air to become a conductor. Scientists don’t
know what causes the air, which is normally an insulator, to collapse in electrical
breakdown and carry the charge of a lightning bolt.
The main effects produced by electric current are magnetism, heating, and
voltage drop across resistive conductors. Any flow of electrons sets up a combined
electric and magnetic field around the current, which in turn affects other electrons
nearby. Electrons and protons carry electric charges of equal strength. When
electrons move away from an area, it becomes positively charged, and the area to
which they move becomes negatively charged. Direct current is a more or less even
flow, as opposed to the instantaneous discharge of static electricity as sparks or
lightning, or the alternate currents that power most our appliances. If there is no
conductor the electric potential between two objects can build until a violent burst
of current equalizes the charges, such as when bio-lightning strikes.