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Static electricity occurs when there are
an excess of positive (+) or negative (-) charges on an
object's surface. This condition is caused from rubbing
certain materials together. Static electricity is not
caused by friction, as is popularly thought. The
position of the material in the Triboelectric Series
determines how effectively the charges will be
exchanged.
Causing excess charges
Putting certain materials together and
then pulling them apart causes excess electrical charges
to be created on their surfaces. This can be done by
pushing them together and pulling them apart or by
rubbing the materials together, which is the main way
static electricity is created.
Most matter is electrically neutral.
That means its atoms and molecules have the same number
of electrons as protons. If a material somehow obtains
extra electrons and attaches them to the atom's outer
orbits or shells, that material has a negative ( - )
charge. Likewise, if a material loses electrons, it has
an excess of positive (+) charges. The electric field
from the excess of charges then causes the static
electric effects of attraction, repulsion or a spark.
According to Solar System Model (or Bohr
Model) of the atom, electrons are in orbits or shells
around the nucleus. A maximum number of electrons are
allowed in each orbit. Forces in each atom seek to reach
that maximum number, such that if an element is just one
electron short of the maximum amount in its outer orbit,
it would try to "steal" an electron from another element
that may be just starting its outer orbit. This is the
basis of chemical reactions.
That force will also tend to hold two
different materials together. In that situation, the
force is called the adhesive molecular force. When
different materials are pressed together and then pulled
apart, the adhesive molecular force pulls electrons from
material unto the other. This creates the static
electricity.
You can see this effect with a piece of
Scotch tape or similar tape. First verify that it is not
attracted to your finger. Then stick it to some surface
and then pull it off. Put you finger near the tape and
it will now be attracted to your finger, showing that
there is an excess of charges on the tape.
Not friction
Although your can create static
electricity by pressing materials together and pulling
them apart, rubbing them together works even better,
except in the case of something sticky like tape.
One unfortunate result from saying that
rubbing materials creates static electricity is that
most people think that friction causes the charges to
build up. It is not friction that causes static
electricity, rather it is the adhesive forces that pull
off electrons.
The Triboelectric Series lists materials
according to how likely they are to let go of electrons
or to take on electrons from other materials. Most of
the materials in the Triboelectric Series are complex
compounds and the release or attraction of electrons has
to do with their molecular structure or geometry.
Dry human skin and rabbit fur have the
greatest tendency to give up electrons when rubbed on
something and become positively ( + ) charged. Teflon
and vinyl have the greatest tendency to become
negatively charged ( - ) when rubbed. If you want to
create static electricity, rubbing fur on Teflon should
give the best results.
Static electricity occurs when there are
an excess of positive (+) or negative (-) charges on an
object's surface. You can create static electricity by
rubbing certain materials together. Static electricity
is not caused by friction. The position of the material
in the Triboelectric Series determines how effectively
the charges will be exchanged. |
