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MISCONCEPTIONS PAGE <http://amasci.com/miscon/miscon.html> | ELECTRICAL
MISCONS <http://amasci.com/miscon/elect.html> | ELECTRICITY ARTICLES
<http://amasci.com/ele-edu.html>

WHY IS ELECTRICITY SO HARD TO UNDERSTAND?

A collection of various ideas.

(C)1995 William Beaty <http://amasci.com/me.html>

*
For a few years I collected a file on the reasons I found "Electricity" so
hard to grasp.  As I slowly learned new ways to understand the subject, I
kept discovering new ways in which I MISunderstood it, and kept adding to
the growing pile pile.  It became large, and soon I also was discovering
parts of electricity that other people found confusing, as well as
concepts which were being explained by text books in a misleading way.  

Below is the result.  Someday I'll try to include all the hand-drawn
diagrams as well.
*

*Why is electricity impossible to understand? Because of...*

1. *Definition of "Electricity"
<http://amasci.com/miscon/whyhard1.html#def> *
2. *Misconceptions <http://amasci.com/miscon/whyhard1.html#miscon> *
3. *Electric Current <http://amasci.com/miscon/whyhard1.html#cur> *
4. *Electric Energy <http://amasci.com/miscon/whyhard1.html#ener> *
5. *Electrostatics <http://amasci.com/miscon/whyhard1.html#stat> *
6. *Electric Fluid <http://amasci.com/miscon/whyhard1.html#flu> *
7. *Electric Charge <http://amasci.com/miscon/whyhard1.html#char> *
8. *Misc. <http://amasci.com/miscon/whyhard1.html#misc> *

* *

*1. PROBLEMS CAUSED BY THE DEFINITION OF THE WORD "ELECTRICITY"*

*Why is electricity nearly impossible to understand? Because of...*

* *

*...misuse of the word "electricity."  Using Electricity as the single name
for several completely different substance-like quantities, while at the
same time expecting students to extract each differing meaning of the
"electricity" from the way we use it in explanations.  Unfortunately,
students instead become permanently confused because they don't realize
that the word has several definitions, they hear one word and assume we're
talking about one single entity.  As a result, they hear us describe a
single "electricity-stuff" having contradictory, confusing, totally
impossible behavior.

...because we misuse the word "electricity."  Using it to name 
physical entities
and also classes of phenomena.  Students may end up believing that
static, current, electrons, and protons are various types of energy!

...we misuse "electricity" in early grades, then never point out our
earlier misuse during more advanced grades.  We're never up-front with
high-school students about the misconceptions they probably acquired in
K-6.  Why can't we specifically teach kids about this "electricity"  
definition problem?

...because of our ignoring the contradiction between descriptions of
"kinds" of electricity.  There are ONLY two kinds of electricity, pos and
neg electricity!  No, there are ONLY two kinds, static and current.  No,
electricity is a CLASS OF PHENOMENON with many types, like Bioelectricity,
Piezoelectricity, etc.  No, there is ONLY ONE kind of electromagnetic
energy, therefore there is only one kind of electricity.  ...All these
statements are both right and wrong: used alone they are accurate only
because "Electricity" has so many distinct definitions.  But because these
statements contradict each other, collectively they are a serious error.

...because of "simplifying" a number of distinct concepts by collecting
them under the single name "electricity," with the result that students
come to believe in a nonexistent stuff called "electricity" which has
contradictory, confusing, and impossible characteristics.

...because of using the presence of multiple definitions of "electricity"  
in dictionaries to legitimize contradictory use of the word in classrooms.  
But just because a dictionary records the various contradictory
definitions, this doesn't constitute an authoritative approval of their
use.

...because of using the physics-term "quantity of electricity" to
legitimize other misuses of the word "electricity."  Physicists use the
word "electricity", and this means that all OTHER definitions are OK?  
But "quantity of electricity" means charge.  So physicists are actually
(indirectly) saying that it's NOT correct to believe that electricity is
anything but charge, that electricity is NOT energy, electricity is NOT
the flow of electrons, or classes of phenomena, etc.

...because of mistaken belief that "electricity" travels one way, from
source to load... and at the same time it travels in a circle and returns 
to the source.

...because of mistaken belief that "electricity" travels at the speed of
light, while at the same time it flows along at inches per hour.

...mistaken belief that "electricity" alternates and flows back and forth
at 60HZ, while at the same time it flows continuously forward from source
to load. 

...mistaken belief that "static electricity" is "electricity" which is
static and unmoving. 

...use of familiar terms with unfamiliar definition causes confusion.  For
example, in electrical science "AC" does not mean "alternating current". 
Instead it means "having changing value."  So a constant voltage is called
DC, and a changing voltage is called "AC," and the term "AC voltage" is
commonly used.  Does "AC voltage" mean "Alternating Current Voltage"?  No,
that would be silly.  AC voltage is changing voltage.  An "AC signal" may
be entirely composed of electrostatic fields and have nothing to do with
current.  But if you believe that "AC" means only "Alternating Current",
you will be confused by electrical explanations.

...wrongly assuming that students are as adept as their instructors when
it comes to manipulating concepts.  Some instructors know that
"electricity" has multiple meanings, and therefor we must take the word in
context to see what the intended meaning is.  But students don't know
this, they think we are using a single word, and so must be discussing a
single concept.  We end up convincing them that a single entity called
"electricity" exists which has confusing, contradictory attributes.

...textbooks start with basic assumptions about "electricity," and then
expand on these.  But if the basic assumptions are never critically
examined, they may or may not be correct.  (Example: K-6 books assume that
a single substancelike entity called "electricity" exists.  Another: there
are only two kinds of "electricity.") 

...invisible war between old and new definitions of "electricity."  The
word was originally used to mean "electric fluid."  As the concepts became
refined, the Electric Fluid changed into "charge," so a quantity of
electricity was simply a quantity of charge.  But in recent decades the
word has been usurped by electric companies, and now usually means
"energy."  But this leaves a gap, since "electric fluid", or stuff-flowing
in-wires now has no common name.  The word "charge" is often used instead,
but this is misleading, since a wire can have no "charge" even while there
is flowing charge within it.  Even more often, the word "current" is
incorrectly used instead of "electricity", as in "flow of current."  But
lots of older literature still contains the older definition, and states
that "electricity flows inside of metals."  Modern authors may unknowingly
take older explanations to heart and believe that they were discussing
energy, not knowing that the older works were discussing an entirely
different "electricity" than is found in modern texts.

...incorrect popular conceptions of electricity which must be unlearned
before accurate concepts can ever be understood.

...mistaking the wave for the medium.  Is "electricity" the electrons, or
is it the wave of energy that flows THROUGH a column of electrons.
Think of how difficult it would be to understand sound waves and air
pressure if we had just a single word that meant both "sound" and
"air."

...mistaken belief that "generate electricity" means "create electrons." 

...belief that a single "electricity-stuff" flows in circuits, when
actually there are several different types of "stuff" which can flow: 
charge flows slowly around a circuit, while energy propagates from source
to load at high speed, while net-charge and current also propagates fast
in various directions. Charge flows down one wire and back up the other,
while energy flows down both wires and does not return.

...mistaken belief that electric current is charges flowing inside wires
at the speed of light.  The charges actually flow at inches per hour.

...mistaken belief that net charge and charged particles are synonymous. 
However, a wire can have no net charge, yet its mobile electron-sea can
flow.  An "uncharged" wire which has equal amounts of protons and
electrons can contain a huge electric current.  Is there "charge" inside
the wire?  But the wire has no "charge!" 

...mistaken belief that "current" and "static" are substances.  The only
substance here is electrons and protons.  They cause the phenomena called
"static" (electrons separated from protons) and "current" (groups of
electrons moving in relation to groups of protons).  "Static" and
"current" are events.  They are happenings, not substances. 

...mistaken belief that a phenomenon is "made of electricity," when the
phenomenon is really just "electrical."  If we say that lightning is
"atmospheric electricity", then we mean that it is an electrical
phenomena, and should then never say that lightning is "a type of
electricity," or that it is "made of electricity".  Doing so would be like
saying that clouds are "composed of weather,"  and the little droplets in
a cloud are made of a liquid called "weather." 

...mistakenly confusing electrical phenomena with electrical quantities. 
Lightning is "electricity" because it is an electrical phenomenon.  But
lightning is not electrical energy (the energy actually flows INTO the
lightning bolt from the surrounding space) and lightning is not electric
charge (the lightning can strike much faster than the electrons move, and
the flowing electrons often move in the opposite direction from the
direction of the lightning strike)  So, lightning may be "electricity,"
but in the same way that batteries and bulbs are also a form of
"electricity": they both are electrical. 

...belief that there are only two types of electrical phenomena: static
electricity and current electricity.  In fact, there are many many others. 
Lightning is Atmospheric Electricity (and since it involves both AC and
DC, electrostatics and electric current, it could also be called Impulse
Electricity.)  Heart-muscle phenomena is Myoelectricity.  Then there's
Piezoelectricity, Triboelectricity, Contact Electricity, Bioelectricity,
Photoelectricity, ...

...mistaken belief that "static" and "current" are opposites.  Yet
pressure is not the opposite of flow.  The opposite of Static (or
separated +- charge) is not Current (or flowing charge.)  The opposite of
Static is cancelled charge; neutral matter.  The opposite of MOVING
cancelled charge is not separated charge, it is UNMOVING cancelled charge. 

...mistaken belief that electric energy flows THROUGH an appliance and
returns to the generator.  Only the charges do this, not the energy.  The
appliance acts as an energy absorber.

...mistaken belief that energy flows out of a battery through one wire,
then flows back through the other.  The charges do this, while the energy
flows along BOTH wires in one direction, from source to load. 

...mistaken belief that, in an AC system, electric energy vibrates back
and forth.  It is the charges, not the energy, which vibrates like this. 
The energy flows forward continuously.  It's like waves on water, or sound
in the air: the medium wiggles as the wave-energy proceeds forward. 

...wrongly describing the presence of electric current as "electricity" 
and the lack of current as "no electricity," when actually the flowing
charges which cause the current are present whether they move or not. 
Analogy: when water stops flowing in a pipe, the water doesn't disappear. 
And when an electric current is halted, the charges remain in the wires,
which is the place where they started.

...little use by educators of the wind/sound electrical analogy:

	- AIR is a physical substance.  
	- Sound is a wave that propagates rapidly through a volume of air.
	- Wind is a flowing motion of air.

	- ELECTRIC CHARGES are a physical substance.  
	- ELECTRIC ENERGY is a wave that can propagate along a column of
	  charge.
	- ELECTRIC CURRENT is a flowing motion of the charge.

Confusion between charge-flow and energy -low is similar to confusion
between wind and sound.  Believing that electrons flow at the speed of
light is similar to believing that air molecules travel at 720mph along
with the sound wave. *

* *

*2. PROBLEMS CAUSED BY WIDESPRED STUDENT MISCONCEPTIONS*

*Why is electricity impossible to understand? Because of...*

*...student misconceptions which over the years have managed to invisibly
infect textbooks, and reference books, and even educators. 

...widespread assumption that textbooks are nearly 100% accurate.  This
causes us to be overly trusting of textbooks, and so we ignore any slow
increase of errors in the books.  It makes us unknowningly spread the
authors' misconceptions.  When we do notice misconceptions, we either
remain in denial about them or we minimize their importance.  Our
assumption that textbooks contain only minor flaws causes us to be
threatened by anyone who points out serious errors or attempts to correct
them. Lack of a critical viewpoint leaves textbooks wide open for creeping
"infection" by increasing amounts of misconceptions.

...widespread assumption that textbooks are nearly 100% accurate.  We
remain in denial that they are imperfect, and this keeps students in the
dark about the need to take all textbook assertions with a grain of salt.
It hides from them the need to constantly examine themselves for the
presence of misconceptions.  As a consequence, they may never learn that
hard work is required to assemble and CREATE their knowledge.  Instead
they end up sitting back and being spoon-fed a group of disconnected,
possibly misleading facts.  If we stop uncritically accepting the contents
of books, we might finally become aware of the necessity of learning
concepts rather than memorizing facts.

...widespread assumption that textbooks are nearly 100% accurate.  This
keeps students from complaining about bad textbooks and teaching.  If
curriculum materials are assumed to be perfect, the fault must lie with
the student.  But if they could instead always regard curriculum materials
with a critical eye, they might demand improvements.

...assumption that student misconceptions always arise mysteriously within
the students, when in fact these misconceptions are often specifically
taught in earlier grades.  E.g.: the constant current battery
misconception.  In grades K-6, kids are hammered with the concept that
batteries are sources of "current electricity."  High school physics
teachers then complain that the kids believe that batteries always put out
the same current regardless of the load.  The solution isn't to figure out
better teaching methods in highschool physics, the solution is to send a
million complaints to the publishers of the misleading K-6 curriculum
materials!

...textbooks lack discussion of common flaws and misconceptions.  Books
tell us all about electricity concepts, but never go into detail about
possible conceptual pitfalls to avoid, and don't expose us to the idea
that the recognizing and eliminating of misconceptions is a powerful
learning technique.  They don't stress the fact that the WRONG answers are
of tremendous value, that wrong answers shouldn't be punished or hidden
away in embarrassment. 

...avoidance of discussion of misconceptions in the classroom.  Common
misconceptions aren't specifically attacked in school.  If learning cannot
progress until a misconception is UNlearned, then a student with a
misconception can waste years in futile attempts to progress.  Talented
kids may needlessly abandon physics as "too hard," when the fault actually
lies with their distorting "mental filter" created by an unexamined
misconception.  (E.g.: when kids believe that current is a substance, all
accurate info on electricity will be interpreted under this assumption. 
As a result it will be twisted into useless garbage, while periodic
textbook assertions that "current flows" will keep reinforcing the
students' misconception.)

...students blaming themselves.  Electricity is thought to be abstract,
complicated, confusing, mysterious, and invisible, with behavior which
frequently goes against common sense, and anyone who can't understand it
has just not worked hard enough.  No.  In fact, electricity EXPLANATIONS
are contradictory, confusing, needlessly abstract, and frequently go
against reality and common sense.  But students who have difficulties
understanding them will not blame books and instructors, they will put the
blame on themselves.  Therefor no one will feel any need to improve the
situation.

...mistaken belief that the understanding of electrical physics only
involves the memorizing of right answers, and that the concept-networks,
the STORYTELLING part is not important.  This allows us to blithely teach
sets of contradictory concepts, since each concept may be accurate when
examined on its own.  Example: electricity travels at nearly the speed of
light (yes, this is true if "electricity" is defined as meaning "EM
energy." ) Example: electricity is composed of particles called electrons
(yes, if "electricity" is defined as meaning "charge")  But the student
will never grasp electrical physics now, because these two concepts turn
to garbage when combined.

...explaining things in certain ways because it is traditional to do so,
rather than explaining things in certain ways because it gets the concepts
across well.  "That's the way everyone does it, so it must be right." 
"All the textbooks do it this way, and that many books cannot be wrong."
E.g.: we always say that current flows out of battery, through lightbulb,
back to battery.  Why not alter this to read: charge comes out of
*lightbulb,* is sucked into the battery, is spit out of other battery
terminal, then flows back to the bulb?  The traditional explanations
muscle their way into all textbooks and wipe out creative alternate
models.*

*^ UP ^ <#top> *

*3. PROBLEMS INVOLVING THE "ELECTRIC CURRENT" CONCEPT*

*Why is electricity impossible to understand? Because of...*

* 

...mistaken belief that generators and batteries send out a substance
called "current" to appliances.  This is coupled to the mistaken belief
that there is no path for current THROUGH a battery or generator.

...continuously stating that "current" flows.  This tends to convince
everyone that a substance-like entity called "current" exists, and
steers us away from use of the "charge flow" concept.  In any piece of
written text, always test for this by replacing the term "current" with
the term "charge flow"  to see how it reads.  Most explanations will then
say that "charge flow flows", but some even say that an electron is a
particle of "charge flow" rather than of charge.

...mistaken belief that since batteries and generators CAUSE electric
currents, they must be PRODUCING a substance-like stuff called current.
Or, since batteries and generators cause a flow of "electricity,"  
wrongly assuming that they must be CREATING an electricity-stuff.  In
fact, the charges were already in the wires to begin with, and
batteries/generators simply behave as charge-pump devices.

...use of confusing term "amount of current."  Current is a rate, not a
substance-like quantity.  We always should say "what is the rate of
current," or "intensity of current", or "what is the value of current." 

...wrongly mixing "quantity of a substance" with "flow rate" concepts. 
This mistake occurs not only in electricity.  Does a shower use lots of
water?  Meaningless, since the length of time is not given.  Is a high
current a flow of "lots of electricity (charge)?"  Meaningless!  Is a
1000W lightbulb a user of "lots of energy?"  Meaningless.  A 1000W bulb
uses energy at a GREATER RATE than a smaller bulb.  If I turn on a small
bulb for a year, versus a large bulb for a microsecond, the small bulb
uses way more energy. 

...incorrectly stating that electric current is "amount of electricity," 
rather than "amount of electricity per unit time."  "Amount of charge per
unit time" would be a better way to say it, of course!

...mistaken belief that a device which causes current must be a source of
charge.  Belief that generators "supply current" (i.e. charges) rather
than simply pumping them.  This idea is supported everywhere by the term
"source of current," which should more clearly be written as "cause of
current."

...taking electric current as a fundamental entity (maybe because of the
NIST amp-seconds physical standard), and so not exploring deeper concepts
involving electric current as flow of electric charge.

...mistaking the high-speed chaotic vibration of electrons for the
low-speed motion of electric current.  (analogy: learning that air
molecules individually move very fast, and therefore believing that the
earth must experience constant hurricane-speed wind.)  In fact, high speed
air molecules imply HOT air.  The hot air is unmoving.  And the high speed
of electrons acts like thermal vibrations, like heat in the metal object,
not like overall motion of an electrical current.

...mistaken belief that all electric current is a flow of electrons.  It
is not.  This connects with the misconception that "electricity" is
composed only of electrons.  As a result, we tend to ignore the common
non-electron currents in electrolytes, in semiconductors, nerves, the
ground, oceans, batteries, corona, etc.  If only charged atoms flow
between the plates in a battery, and no electrons flow there, we may
incorrectly believe that the path of electric current is not THROUGH the
battery, when in fact it is.   This misconception destroys the whole 
concept of "electric circuits", since we mistakenly believe that batteries 
are open circuits.  Wrong, a battery is a closed circuit, because if it 
was not, then battery-powered circuits could not even exist.

...mistaken belief that "electricity" obeys strange quantum-mechanical
rules, and therefore "electricity" must be very different than normal
matter.  This connects with the incorrect belief that "electricity" is
made of electrons.  But while electrons do display significant QM
behavior, electric charge in general does not.  If one believes that only
electrons are important, then one may mistakenly believe that the
strangely enlarged quantum-mechanical behavior of the low-mass electrons
applies to all currents and quantities of charge.  Electric currents don't
have significant QM features, only *electron* currents have these
features.  True, electrons are so low in mass that they sometimes behave
as waves, and their motion in metals is very far from classical views of
physics.  But ion-based electric currents are very common phenomena in
everyday circuits, and ions are massive enough that the QM behavior is
vanishingly small.  Many of the purported quantum-characteristics of
electric current vanish when currents take place in tubes full of
electrolyte. Electrons may behave strangely, but this doesn't mean that
charge in general behaves strangely.  Electrons may vibrate chaoticly at
the speed of light in metals, but this doesn't imply that "electricity"
does this inherently.

...mistaken belief that no charge flows through batteries.  (No electrons
flow through them, so there cannot be current?)  This leads to the
traditional incorrect flashlight-current explanation (current comes out of
battery, flows...etc.)  It also leads to the misconception that batteries
SUPPLY CHARGE, and have a storage place for "used" charge.  This might
make sense if we believe that there's no path for charge through the
battery.  But it's wrong, because there is a path, a path provided by
flowing charged atoms.  Charge flows around and around a circuit, passing
THROUGH the battery over and over. 

...no use of the convenient fact that rate of charge flow is proportional
to charge speed.  This greatly clarifies electric circuit concepts.  High
current is FAST charges.  Zero current is STOPPED charges. 

...describing a conductor as "something through which electricity can
flow," rather than as "something which contains movable electricity."  A
vacuum is a perfect insulator, even though it offers no blockage to moving
charges.  But a vacuum contains no movable charge, so it insulates.

...backwards introduction of electric flow vs. electric substance.  During
teaching, electric current concepts are often explored first, then
electric charge is introduced later if at all.  As a result, students
think they understand Amperes, they have little grasp of Coulombs, and in
fact they may not really grasp either concept.  Students end up thinking
that the Amp is a fundamental unit, they ignore the Coulomb-per-second,
and are confused by the Amp-second. The situation should be reversed: they
should learn all about the Coulomb, hear about current only in terms of
Coulombs per second, and should see the Amp-second as a strange,
roundabout way of saying "coulombs." 

...mistaken belief that since physics defines "quantity of electricity" in
terms of ampere-seconds, quantity of electricity must somehow involve
current rather than charge.  No, its just that physicists in a Standards
lab can measure charge flow and time more easily than they can measure net
charge.  It makes more sense to measure charge, then define the current as
the flow of charge.  Instead, the system of electrical standards first
defines the current, then defines charge as a current which is on for a
certain length of time.  It might not make sense, but a Standards lab is
after measurement accuracy, not sensible pedagogy.

...everyday electrical energy sources operate in constant-voltage mode,
not constant current mode.  We could say that they supply "voltage," not
current.  A battery is not a supplier of "current electricity," it instead
supplies voltage, and various currents are DRAWN by placing various
resistances between the battery leads. 

...mistaken belief that batteries and generators are sources of current,
when, since they are actually constant-potential systems, they are
actually sources of "voltage."*

* ^ Up ^ <#top> *

*4. PROBLEMS INVOLVING ELECTRIC ENERGY*

*Electricity is impossible to understand because of...

...mistaken belief that electric energy is not in the electromagnetic
spectrum, even though it is composed of electromagnetism.  Mistaken belief
that electrical energy is fundamentally different from the rest of the
types of energy in the Electromagnetic spectrum.  Mistaken belief that DC
or 60Hz energy is "electricity," while higher frequencies are "radio." 

...mistaken belief that power is a substancelike entity which can flow. 
Power is actually a FLOW of a substance.  "Power" means energy-current. 
Energy can flow, and its rate of flow is called power.

...mistaken belief that electric energy is made of small particles called
electrons.  Actually, the fundamental unit of electrical energy is the
photon, not the electron, since electrical energy is electromagnetic
field/wave energy.

...mistaken belief that energy flows up one wire, through the appliance,
then back down the other wire.  Energy actually flows up both wires, dives
into the appliance, and is converted to other types of energy (heat,
motion, etc.)

...mistaken belief that electric companies sell electrons.  They actually
sell 60Hz "radio waves", and only use the columns of electrons in the
wires to transmit the waves to the end users.

...mistaken belief that energy flows inside of wires.  Electrical energy
is actually electromagnetic fields.  It exists as the voltage field and
magnetic field which surround the wires.  Electrical energy flows as a
"tube" which encloses a pair of wires and exists only outside the metal.

...assumption that electrical energy is an abstract quantity which can be
ignored, rather than seeing it as the EM wave energy which is sold by
electric companies.

...backwards conceptual construction of power vs. energy during teaching. 
As a result, students think they understand Watts, none have a good grasp
of Joules, and in fact they don't really grasp either concept.  Students
think the Watt is a fundamental unit, they ignore the Joule-per-second,
and are confused by the Watt-second.  The situation should be reversed: 
they should learn all about the Joule, hear about energy flow before
learning that energy flow is the same as "power," and should see the
watt-second as a strange, roundabout way of saying "joules." 

...mistaken belief that individual electrons in wires carry energy along
with them as they flow.  The situation is really like that with sound: the
energy moves as waves through a population of particles.*

* *

*5. PROBLEMS INVOLVING ELECTROSTATICS*

*Electricity is impossible to understand because of...

...mistaken belief that "static" and "current" are opposites.  Yet
pressure is not the opposite of flow.  The opposite of separated charge
(static) is combined charge (matter.)  The opposite of moving cancelled
charge (current) is unmoving cancelled charge (matter.)  Pos and neg
charges which are separated from each other, are not the opposite of pos
and neg charges which flow relative to each other.

...mistaken belief that "static electricity" is "electricity" which is
static and unmoving, rather than separated and "pressurized."

...mistaken belief that when "static" begins to flow and turns into
"current," all the electrostatic phenomena must vanish.

...mistaken belief that when electrons and protons of matter are
separated, they become "static" and unmoving.

...mistaking e-fields for 'static electricity,' as in:  "Teacher, is the
'static' on the surface of the balloon, or is it in the space surrounding
the balloon where my arm-hairs are standing up?" 

...mistaken belief that "static" precludes "current" and vice versa. 
Actually, separated charges can be made to flow, such as in high-voltage
transmission lines, and so we can have "static electricity" that flows.
Conversely, when an electric current is stopped, the suddenly-unmoving
charges do *not* constitute "static electricity", since there is no net
charge.

...mistaken belief that "static electricity" is caused by friction, when
it actually arises from charge separation.

...mistaken belief that "static electricity" only refers to dryer cling
and scuffing on carpets, when in its other guise it really involves all
circuitry.  It's other guise is voltage. 

...mistaken belief that since rubbing fur on a balloon produces electrical
effects, it must be PRODUCING CHARGES.  We should put much more emphasis
on separation of charge, and cut out any talk of "creating charge." 
Charges can be created, but it takes a particle accelerator or a
radioactive source to do so. 

...lack of an electrical term analogous to "magnetism."  E-fields are then
left out of early teaching because "electricism" is not an independent
topic.  When a compass aligns itself, that's magnetism.  When hairs align
themselves in an intense, distantly generated e-field, what's it called? 
Not "static electricity," because the strong charge is far away. 

...significant emphasis is put on teaching of magnetic fields early on,
but e-fields are not taught until more advanced levels.  (In grades K-6,
the e-fields are hidden within the "static electricity" concept and
never specifically discussed.)

...lack of early teaching of the important e-field concepts.  This causes
the "voltage" concept to be seen as complicated and abstract, as involving
mysterious meter measurement which have no connection to anything
visualizable.  Yet "voltage" is "e-field", and we can draw pictures of it! 

...mistaken belief that "static electricity" is caused by the static-ness
or stillness of the charges.  This causes the whole charge-separation
concept to never be explored. 

...electrostatics is skimmed over or ignored completely, yet in large part
electrostatics is a study of "voltage."  Skip over electrostatics, and
your students will forever after be partially confused about voltage.*

* *

*6. PROBLEMS INVOLVING "ELECTRIC FLUID" ANALOGY*

*Electricity is impossible to understand because of...

...mistakenly believing that electric circuits are analogous to open
hydraulic systems (pouring a cup of water through a pipe) when they
actually behave like closed hydraulic systems: a drive-piston connected to
a driven piston, with the connecting hoses pre-filled with water.  This
probably comes about in part when we teach that circuits are like pipes
with water, but students then imagine the faucet at home, rather than the
hydraulic system of a backhoe.

...mistaken belief that the fluid analogy does not apply to circuits
because in wires the ENERGY flows, while in pipes the flow is of a
material.  Mistaken belief that the "fluid" in wires always flows at the
speed of light, while in pipes the flow can be fast, slow, or stopped. 
Mistaken belief that the "fluid" in wires flows from the source to the
load and does not return, while in pipes the water circulates around and
around. This is all incorrect.  Actually the "electric fluid" in wires
flows slowly, not at the speed of light, just as happens in water pipes. 
In wires, the "electric fluid" flows slowly while the energy flows fast,
just as happens in water pipes.  And in wires the "electric fluid" flows
slowly in a circle, just as happens in a pre-filled hydraulic system. 

...the lack of a good name for "cancelled charge."  When + and - come
together, the result is NOT nothing.  The result is matter.  The result
can also be the cancelled-but-mobile "electric fluid" found in all
conductors.  Since matter contains (is even MADE of) "cancelled charge," 
and since electric current in wires is a flow of "cancelled charge," we
should see matter as being made of "non-moving electric current."  Matter
is made of "frozen electricity."  The exception is conductors, which
contain "liquid electricity."  Some common names for the neutralized
mobile charges found in conductors: 
	Electron sea
	combined charge
	cancelled charge
	mobile charges
	mobile ions
	current carriers
	electric fluid

...early teaching about current, yet without teaching about the
"substance"  which flows.  We shouldn't teach about "current" until AFTER
we've taught the "electron sea" concept.  It's like learning about ocean
currents without ever learning that water exists.  It makes "current" seem
needlessly abstract and non-visualizable. 

...mistaken belief that Ben Franklin's one-fluid theory of electricity was
correct, and the two-fluid theory was wrong.  In fact, matter contains pos
and neg, or two kinds of "electricity."  Ben though that pos and neg was a
surplus or deficit of a single sort of electric fluid.  Not so, because
matter turns out to be COMPOSED of positive and negative particles, so
there are two kinds of electric-stuff after all.

...mistaken belief that early theories of "electric fluid" were struck
down, and so "electric fluid" does not exist.  Ancient experimenters
believed in electric fluid, but today we know better?  No.  Today we know
that wires contain cancelled, mobile charges.  Today this is called the
electron-sea of the metal, but "electric fluid" is not an incorrect way to
describe it. 

...misleading explanations of conductors and insulators.  Instead of
saying that conductors allow current, and insulators prevent it, say that
conductors contain mobile charges, while insulators contain immobile
charges. 

...misleading explanation of a conductor as a material which passes
electrons.  Incorrect, since a vacuum offers no barrier to electrons, yet
vacuum acts as a good insulator.  The difference is that a vacuum contains
no mobile charges, so when a potential difference is applied, no current
results.  A metal conductor doesn't pass electrons, instead, a metal
conductor contains movable electrons. 

...mistaken belief that electric current is a flow of energy, when it is
actually a flow of matter.  (our beliefs about energy tend to make us
avoid ever teaching the fact that electric current is a matter flow.) 

...use of the term "current carriers."  This connects with the mistaken
belief that current is a fundamental entity, rather than seeing charge as
fundamental, and seeing current as simply a flow of charge.  After all, we
wouldn't say that the water molecules in a river are "water current
carriers".  Wires are full of mobile charges, not "current carriers."

...misleading description of wires as "hollow pipes."  Ex: wires conduct
electricity, metals conduct charge.  Saying it this way covers up the fact
that metals CONTAIN vast amounts of mobile charge already, and it paints a
distorted picture of the situation.  Better to say "the cancelled charge
inside metals is mobile," or "the charges found in wires can be made to
move." 

...mistaken idea that electric charge in metals is gas-like and easily
compressible. Actually, the cancelled charge within wires is fluid-like,
very difficult to compress, and energy can be transported very rapidly
(rigid rod analogy.)

...little use by educators of slow-electron-flow concepts.  Ex: electrons
flow like the minute hand on a clock, and if they were to flow fast enough
that you could see a movement, that wire would be heated white hot by
"friction."  The electric fluid acts like tar: it stops instantly when the
pressure is removed, gets hot from friction when forced to move, never
moves very fast, large flows require huge pipes, small pipes are subject
to very high friction, and fast movement always implies immense heating. 

...mistaken "empty pipes" analogy.  Wires actually behave like pipes full
of water, with NO BUBBLES ANYWHERE, so when more water is pushed into one
end, water immediately flows from the far end.

...mistaken "swirly water" analogy.  If water is injected into a bowl, it
just makes the mass of water flow in loops, and we mistakenly believe that
the same holds true within pipes.  But in a pipe, if more water is
injected into one end, the entire column of water advances as a unit, as
if it were a solid rod.  In pipes, water behaves like a solid drive belt.

...mistaken belief that since electric current is invisible, the charges
in an electric current are also invisible.  Little use by educators of the
convenient fact that electrons are visible.  "Electricity" is always said
to be invisible, yet the mobile charges within wires constitute a silver
liquid.  The milk in a glass bottle may never be seen to move when stirred
(no bubbles!) but that doesn't mean that the milk itself is invisible.

...little use by educators of the drive-belt analogy.  Electric circuits
are like pulley/belt systems, the electron-sea within a metal wire is like
the rubber belt.  When one part is moved, the whole thing turns, when one
spot on the belt is clamped, the whole thing stops, no rubber or electrons
are consumed, the belt moves slow in a circle while the energy moves fast
in waves, the belt is not invisible and neither are the charges,
back-and-forth motion sometimes works better than continuous rotation (AC
vs DC), friction causes heat and even light, pulleys can drive or be
driven (motor/generator duality), pulleys are not a source of rubber and
batteries are not a source of electrons, and when the belt or the circuit
is stopped, the rubber or electrons stop in place and forever remain.  And
belt-systems were in actual use until supplanted with generators and
wires.

...the discovery of the electron is mistakenly interpreted as suggesting
that electric fluid does not exist.  This is analogous to a mistaken
belief that the discovery of water molecules implies that water is not a
liquid.  Electrons and protons are fundamental particles of the electric
fluid, in a similar way that the molecule is the fundamental particle of a
macroscopic material fluid.*

* *

*7. PROBLEMS INVOLVING ELECTRIC CHARGE*

*Electricity is impossible to understand because of...

...misuse of the word "charge," using it both to refer to a charge of
energy (capacitor, battery) and a quantity of electric charge.  A
"charged" battery contains just as many electrons as a "discharged"
battery, because batteries store their energy as chemical fuel, a battery
is simply a chemically-fueled electron pump, and is "charged"  with
chemical fuel, not with electrical energy.  A fully charged battery
contains the same net electric charge as a discharged battery.  (yet it
contains huge amounts of matter, which is made of charge!) 

...the word "charge" is used to refer to net-charge and to
cancelled-charge.  Students will see "charge" as following conflicting
rules, yet their instructors act as if no conflict exists.  But there is a
conflict: an object with zero net charge is still full of charges, and an
uncharged object will behave very differently that will empty space (ex: 
heating of neutral metal by induction, while empty space is not heated
even though it is neutral.)  And fast waves of net-charge can propagate
through populations of barely-moving charges.  Groups of charges can have
zero net charge, so do they not exist?  And neutral circuitry can support
enormous charge flows (current) yet have no net charge at all, so how can
there be charge flow if there's no charge?

...a problem with the word "charge": an object with a dipole charge
distribution is "charged," and if the charges come together , the object
is "neutral," yet no charged particles were destroyed, and in fact the
same quantity of charged particles are still there.  So two charges far
apart equals "charged," while two close together means "uncharged?"  But
the particles never lose their charges, so the quantity of charge never
varies!

...a problem with the word "charge": when a battery is suddenly connected
to a pair of long wires leading to a distant lightbulb, the wires become
charged and a wave of net charge propagates along the wires at the speed
of light.  Yet the individual electrons, the "sea of charge," flow slowly
around the circuit.  So did the charge go fast or slow?  Depends on
whether "charge" means the electron sea, or whether it means the imbalance
in quantities between the group of electrons and the group of protons in
the wire. 

...a problem with the word "charge":  A capacitor is briefly connected to
a battery, so energy is stored in the capacitor.  If the leads of the
capacitor are now touched together, charge moves from one plate to the
other.  Does the capacitor now contain less charge?  Yes, because its
plates are now uncharged.  No, because the total quantity of electrons and
protons never changed (each electron that left one plate ended up on the
other plate.)  A "charged" capacitor contains exactly as many electrons as
an "uncharged" one.  Charge imbalance is called "charge", but electrons
and protons are also called "charge." 

...mistakenly trying to combine the particle-physics use of "charge" with
the everyday-world use.  In the everyday world, when positive and negative
charges are combined, the result is neutral matter.  In particle physics,
a combination of positive and negative charge can result in many different
things (gamma rays, if positrons and electrons annihilate.)  In particle
physics, oppositely charged particles can be created from empty space.  In
the human world, neutral matter must first be present before pos. and neg. 
charges can be separated out: fur and rubber can "create" opposite
charges, but empty space cannot.  So, in the everyday world, opposite
charge can fall "together," only to be separated at a later time.  In
particle physics, if you touch a pos to a neg, the particles are GONE. 
This is all a question of microscopic energy levels, of chemistry versus
nuclear effects.  But circuitry and electrical science involves atoms, it
does not involve high energy particle annihilation. 

...mistaken belief that when a positively-charged wire is connected to a
negatively-charged wire only the negative net charge moves as the charges
cancel.  Actually the positive and negative net charges both move, they
flow together and vanish.  The net charge is of course an imbalance
between pos. and neg. charged particles, and it is true that only the
negative particles moved.  Net charge is the /difference/ between
quantities of positive and negative particles, and the net charge can move
differently than particles.

...ignorance of the existence of neutral charge.  If we add the number of
particles in equal quantities of positive and negative charges, we get a
larger number: the total number of charges.  If we subtract the negatives
from the positives, we get zero, the net charge.  The sum is linked to the
amount of matter and to the amount of electron-sea able to carry current
in a metal.  The difference is linked to the e-field surrounding the
object and to the charge-imbalance on its surface.  It's wrong to call the
sum and the difference both by the name "charge."  For example, an
uncharged wire can carry a large charge flow.  Does the wire contain zero
charge, since it is uncharged?  Or does it contain an immense charge,
since it contains moving electrons?

...mistaken belief that "electricity" involves only electrons.  For
example, mistaken belief that "static electricity" is the excess or
deficit of electrons.  In fact, positive net charge is not a lack of
electrons, it is an imbalance, it appears whenever there are more protons
than electrons, and fewer electrons than protons.

...mistaken belief that "electricity" involves only electrons.  For
example, mistaken belief that conductors contain movable electrons.  This
is true only of metals, and is not true of water, human flesh, sparks,
neon signs, batteries, currents in the earth, etc., etc.

...mistaken belief that "electricity" involves only electrons.  For
example, mistaken belief that "electricity" cannot be easily explained,
since electrons are both waves and particles.  But the flowing electrified
atoms in a non-metal conductor are easily localized, and are even visible! 
The bizarre Quantum Mechanics which applies to electrons does not apply
to "electricity" (meaning charges) in general.*

* *

*8. MISC.*

*Electricity is impossible to understand because of...

...mistaken belief that electricity is a glowing blue "crackly" substance
(mistaken belief that sparks or lightning bolts ARE electricity.) 

...mistaken belief that electricity is a substance that feels tingly. 
But high voltage causes body hair to repel and rise.  The charge itself
has no "feel."  And during an electric shock, the creation of ion currents
in your hand will be felt by the nerves, but the ion-charges were there to
begin with, and only their MOTION causes a tingling sensation.

...mistaken belief that atoms cannot be torn apart.  Belief that an atom
smasher is required.  But all of chemistry, and all of basic electrical
physics, is based on torn-apart electron shells.  It's only the atoms'
nuclei which are never disrupted.

...mistaken belief that electrons in conductors must be forcibly pulled
from individual atoms before an electric current can commence.  The
"jumping electrons" misconception. 

...mistaken belief that famous people have the "right answers."  Example:
if we want a good explanation of electricity, we take the writings of a
famous physicist as gospel, as the single best way to explain it.  But
what if that physicist was a lousy educator?  Skill in science doesn't
lead directly to skill in explaining what one knows.  Fame does not
automatically make one into an ideal teacher, so in order to find a good
way to teach, look for good ways to teach, don't look for famous people to
copy.

...mistaken belief that in order to create teaching techniques at lower
levels, we simply take the techniques used at higher levels and simplify
them.  However, the techniques used to teach college science students are
aimed at a population which lives in a very different world than do K-6
teachers and students.  Educational material tailored to train scientists
is written in a different "language" than the one used at the K-6 level.
Advanced material cannot just be simplified, it also must be "translated."
It must use concepts relevant to the world in which its audience lives. 
It must do this to such a great extent that a K-6 explanation might better
be created from scratch, rather than being derived from college physics. 

...mistaken belief that, when it comes to explanations, there is one Right
Answer.  Wrongful pursuit of a single "perfect" way to explain
electricity.  This goes against the way people grasp concepts.  To
paraphrase the physicist Richard Feynman, "If you can't explain something
in several independent ways, then you don't really understand it."  Give
up looking for the "correct" explanation, instead try to learn as many
different competing explanations as possible.  If one of those blind men
had known that an elephant was a rope, AND a leathery wall, AND a moving
hose, AND a heavy stump, he might have synthesized a sensible view of the
whole animal.  The situation with electricity is very similar.  We can
only begin to grasp the nature of that invisible elephant by acquiring
many separate and seemingly incompatible viewpoints.
*

*Some references for Misconception research*

*   Bill Beaty's internet WWW page:
http://amasci.com/miscon/miscon.html

Proceedings of The 2nd Int'l Seminar - Misconceptions and Educational
Strategies in Science and Mathematics, July 26-29, 1987.
Cornell U., Ithaca NY. Vol II and III. On microfilm from ERIC
Document Repro. Services.  (available on internet, see above)

Mario Iona, WHY JOHNNY CAN'T LEARN PHYSICS FROM TEXTBOOKS I HAVE KNOWN
Millikan Award Lecture, Am J. Phys. 55 (4) Apr 1987 pp299-307

Mario Iona, WOULD YOU BELIEVE... Series of columns in The Physics
Teacher (AAPT Publication)

Mario Iona, HOW SHOULD WE SAY IT? Series of columns in The Science
Teacher, 1970-1972

*

* Created and maintained by Bill Beaty <http://amasci.com/billb.html>.
Mail me at: <http://amasci.com/amfrm/>.
*