|
|
What's the Difference Between
'Static' Electricity and
'Current' Electricity?
1997 William Beaty BSEE
This is a really tough question to answer. It's not hard because it's
complicated, it's hard because dictionaries contain several different
definitions for each of these words, and some of them are wrong.
Perhaps you'd rather see the answer to a slightly different question:
What is "static" electricity?
What's the difference between Electric Charge and Electric
Current?
If you ask "what is Static
Electricity?" or "what is Current Electricity", different people will give
you different answers. This happens because people cannot agree upon the
meanings of the words "static electricity" and "current
electricity". This is a serious problem. In science, we want a
term like "static electricity" to have just one meaning. When a
scientific term aquires
several different meanings, people become confused, and they can get into
useless arguments about what "static" and "current" really are.
Here is a possible solution to this problem. Don't ask "what is the
difference between static and current electricity". Instead ask "what are
the various definitions of the words 'static electricity' and 'current
electricity'?" Also ask "how do the meanings of the words cause trouble?"
DEFINITION ONE:
Static and current electricity are not stuff, they are not energy.
Instead they are subject areas, they are groups of things which happen.
In technical terms, they are called "classes of phenomena".
What exactly is a "class of phenomena?" Here's one example: weather.
"Weather" is not a stuff, neither is it a form of energy, but
if you investigate the sky, you will find lots of "weather" up there.
Weather is not made of H2O molecules or nitrogen or light rays, yet
weather involves
water, and air, and sunlight. Weather is a class of phenomena, it is a
bunch of different things that people group together. Human
beings
created the idea of "weather", and human beings decide when something is
"weather" or when it is not. Water is "weather" if it is falling as rain,
but water in a bucket is not "weather," even if the bucket is full of
rainwater.
Under Definition 1, the word "electricity" means "electrical phenomena."
In that case "electricity" is a thing very much like "weather." It
doesn't really exist except in our minds. "Electricity" is a bunch of
electrical happenings which human beings have grouped together. Looking
for "electricity" inside wires would be as foolish as collecting
rainwater in order to look for tiny pieces of "weather" in the water.
Under definition one, ELECTROSTATIC EVENTS occur whenever positive and
negative electric charges are held apart from each other. When you comb
your hair on a dry day, and then you find that your comb can pick up bits
of dust ...then that is a static electric occurrence, it is an example of
"static electricity." But watch out: there is no "electricity" in the
hair or in the comb. Instead, the rising hair IS the "static
electricity." The crackling sounds ARE the "static electricity", in the
same way that rain and wind and sunshine are the "weather".
Under definition one, ELECTRIC CURRENT EVENTS occur whenever positive
charges flow through negative charges, or when negative charges flow
through positive charges. When you turn on a flashlight, the charges that
are already within the wires will begin begin to flow. The light bulb
lights up, and the whole thing is a current-electric happening. It is an
electrical phenomenon; an example of "current electricity." But no "current
electricity" flows in
the wires. Instead, the lighting of the bulb, the turning of the switch,
the magnetic fields around the wires, and the unseen motion of the
charges, all these things *are* the "current electricity". They are
electrical happenings, electrical phenomena, therefore they are
"electricity." Under Definition One, "electricity" means "electrical
phenomena."
DEFINITION TWO
There's another completely different way to think about the words "static"
and "current":
"Static Electricity and "Current Electricity" are two types of science.
Just as "physics" is a science, and "geology" is a science, there is a
science called "static electricity." In professional circles it is
actually called Electrostatics. And just as "biology" is a science and
"optics" is another, there is a type of science called "current
electricity." Scientists have a more official name for it, they call it
"Electrodynamics." Static electricity is the study of electric charges
and the way they separate and combine. Static Electricity studies the
attraction and repulsion between charges, and the invisible electrical
fields they create. Current Electricity is the study of the flowing or
wiggling of charges, of the magnetic attraction and repulsion they create,
and of the way they can move electrical energy around. Under definition
two, "electricity" is not a stuff and not an energy. It is a science. In
a similar way,
"physics" and "biology" are not energy or stuff. Blood moves through the
arteries and veins, but this is not a flow of "biology". And electric
charge might flow inside wires, but this is not a flow of "electricity."
Electrical science cannot flow in wires!
DEFINITION THREE
This definition appears in books and dictionaries, but it is misleading and
mostly wrong:
Static electricity and current electricity are two forms of energy.
It is misleading to say that they are energy, because this gives everyone
the wrong idea that electrical charges are a form of energy. Charges are
not energy, they are matter, they are part of the electrons and protons
which make up all atoms.
It is misleading to say that 'static' and 'current' are energy, because it
will lead us to believe that classes of phenomena are types energy.
Is weather a kind of energy? Is geology a kind of energy?
Occurrences
are not energy. Classes of phenomena are not real things, they are
collections of happenings which human beings have grouped together.
Definition 3 might also give us the wrong idea that electric current is a
flow of energy. It is not. When charges flow, energy does not flow along
with them. There is actually just one form of electrical energy, not two.
It is
called "electromagnetism." Electromagnetic energy is light waves, radio
waves, magnetic fields, and electric fields. Static electricity and
current electricity are not made of electromagnetic fields, therefore they
are not a form of electrical energy.
However, Definition 3 can be found in dictionaries. People commonly use
the words "static" and "current" to mean "energy." This suggests that,
even though Definition 3 is wrong, Definition 3 is real. It suggests that
the English meaning of "static" and "current" has slowly changed, and that
they now mean "energy" rather than electrical phenomena or electrical
science. Don't forget that dictionaries also contain slang words.
Dictionaries record which words we commonly use, even we use those words
incorrectly, or even if we assign several contradictory meanings to the
words.
WATCH OUT!
If you start to discuss "static" and "current," people will argue with
you. Some people will tell you that Definition One is the real answer,
and that all the other definitions are wrong. Other's will try to
convince you that Definition Two is real and the others are incorrect.
But these people are all wrong, since ALL these definitions can be found
in various dictionaries and encyclopedias. All three definitions are
real. If you prefer one of them, then you have a problem, because there is
no way to erase the others from all those textbooks and dictionaries, and
there is no way to force other people to stop using the alternate meanings
of "static" and "current." And finally, if you want to know what "static"
and "current" really are, you will encounter endless trouble, since the
very words themselves have several contradictory meanings. If you try to
learn the "one true meaning," you will receive crazy answers which don't
make sense..
My advice: avoid the fight entirely. Never use the words "static
electricity", instead say "net charge" or "separated charge" or "the
science of electrostatics". Also, never say "current electricity",
instead say "charge flow" or "electric current", or "the science of
electrodynamics". In this way you can avoid all the fuss, and get down to
understanding the real science which hides somewhere behind all the
confusing and misused words.
Perhaps you'd like the answer to a slightly different question:
What's the difference between ELECTRIC CHARGE
and ELECTRIC CURRENT?
The Electricity Map
'Static' Electricity that Flows
Electricity Misconceptions
Misconception References
All Electricity Articles
COMMENTS
| |