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BELOW are my original, very crude and unedited 1989 notes and "raw data" for Electricity Exhibit, for the Museum of Science in Boston. Some of this material became finished articles on Amasci.com. Why are my explanations different than usual? Because they're based on the defeating of misconceptions: on the painful 'unlearning' I had to go through before I could understand simple electrical physics. I kept a running record of textbook errors, useful simple concepts, as well as my own childhood misconceptions as I discovered them.





WHY IS ELECTRICITY SO
HARD TO UNDERSTAND?
A collection of various ideas.
(C)1995 William Beaty

In 1986-1988 I was working on Holt/Rinehart "Science" (their K6 text,) and also designing electricity devices at Boston's Museum of Science.

I began slowly collecting instances of wrong electricity explanations. Most were misconceptions being spread by the current crop of K6 (grade school) science texts. Others were in mags and newspaper articles. A few were even in dictionaries and encyclopedias. The more I found, the more sensitized I became, and the more I could "see."

In addition I began mining my own head for misunderstandings I originally had as a beginning learner. I couldn't get inside students' heads, but certainly I could get inside my own student brain of long ago. As I slowly learned new ways to understand the subject, I kept discovering new ways in which I'd MISunderstood it myself, and I kept adding to the growing pile. The misconceptions list became large, and soon I also was discovering parts of electricity that the general public invariably found misleading, or parts that were universally explained badly even in physics textbooks. (Advanced texts get the math right, but sometimes the rest of the explanation is faulty.)

Below is the result. It's my big pile of raw unedited notes. Someday I'll try to include all the hand-drawn diagrams as well. (The edited condensed version is http://amasci.com/miscon/elect.html.)

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

  1. Confusing definition of "Electricity"
  2. Mistaken assumptions
  3. Electric Current
  4. Electric Energy
  5. Electrostatics
  6. Electric Fluid
  7. Electric Charge
  8. Misc.

SCROLL DOWN


















 

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

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


...wide 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! 
(This is like confusion over the difference between Geology and rocks, or 
thinking that "Biology" and "living tissue" must be the same thing.)


...we misuse "electricity" in early grades, then we never point out our 
earlier misuse during more advanced grades.  Students end up with 
misconceptions learned early on.  We use "lies to children" to avoid 
complicated explanations, but then we're never up-front with older 
high-school students about the misconceptions they probably acquired in 
grades K-6.  Why can't we specifically teach kids about this problem with 
the definition of the word "electricity?"


...because of our ignoring the contradiction between descriptions of 
various "kinds" of electricity.  We insist that there are ONLY two kinds 
of electricity, pos and neg electricity!  Then we say no, there are ONLY 
two kinds, static and current.  Then we say no, there are many kinds of 
electricity: it's a CLASS OF PHENOMENON with many types, like 
Bioelectricity, Piezoelectricity, etc.  And then: no, there is ONLY ONE 
kind of electromagnetic energy, and electricity is a form of energy, 
therefore there's only one kind of electricity.  ...All these statements 
are both right and wrong: when used alone they are accurate only because 
"Electricity" has so many distinct definitions.  But because these 
statements contradict each other, collectively they become 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 we lack rigorous dedication to truth and clarity, instead 
there's a cover-your-tail attitude where the confusing presence of 
multiple definitions of "electricity" in dictionaries is used to 
legitimize contradictory use of the word in classrooms.  Rather than 
fixing the problem in classrooms, we point to the confusion in 
dictionaries and insist that the classroom problem is acceptable! But just 
because a dictionary records the various contradictory definitions, this 
doesn't constitute an authoritative approval of their use by teachers.


...because we use the physics-term "quantity of electricity" to legitimize 
other misuses of the word "electricity."  Physicists use the word 
"electricity" in a very narrow sense, but does this mean that all OTHER 
definitions are OK?  But "quantity of electricity" means just one thing: 
it means charge, measured in coulombs.  In other words, physicists 
actually say (indirectly) that it's NOT correct to believe that 
electricity many other things besides coulombs of charge.  They're saying 
that electricity is NOT joules of energy, electricity is NOT the flow of 
electrons, or classes of phenomena, etc.  They're saying that electricity 
means "charge," and other definitions are popular meanings, not scientific 
ones.


...because of mistaken belief that "electricity" travels one way in wires, 
going from source to load... and at the same time believing that it 
travels in a circle and all returns to the source, without any being used 
up.


...because of mistaken belief that "electricity" travels at the speed of
light, while at the same time it flows along at inches per hour as the 
electrons travel slowly in metals.


...mistaken belief that "electricity" alternates: flows equally 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. 


...mistaken use of familiar terms with unfamiliar definition causes 
confusion.  For example, in electrical science "AC" does not mean 
"alternating current". Instead it means something akin to "having changing 
value."  So a constant voltage is called "DC" even though it's not a 
current.  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; DC voltage is 
unchanging voltage.  An "AC signal" may be entirely composed of 
electrostatic fields and have nothing to do with current, even though we 
call it alternating current "AC."  But if you believe that "AC" means only 
"Alternating Current", you will be confused by electrical explanations 
written by the experts.


...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 therefore we must take the word 
in context to see what the intended meaning is.  But students don't know 
this, they think we're 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 substance-like 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 zero net "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 a 
current is a flow.  Are rivers full of current?  No, water.  Flow of 
"charge" is correct, flow of "current" is not.)  But lots of older 
literature still contains the older definition, and it 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 electron-flow, or is it 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 "wind" 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: the 
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 canceled charge; neutral matter.  The opposite of MOVING
canceled charge is not separated charge, it is UNMOVING canceled 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 travels via a column of charge.
  |__  - ELECTRIC CURRENT is a flowing motion of the charge.

  Confusion between charge-flow and energy-flow is similar to confusion
  between wind versus sound.  Do you know that sound is not wind?  TO
  believe that electrons flow at the speed of light is similar to 
  believing that air must travel at 720mph along with the sound wave. 

2. PROBLEMS CAUSED BY WIDESPREAD 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 unknowingly 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.  Therefore 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 ^

OTHER ARTICLES:


3. PROBLEMS INVOLVING THE "ELECTRIC CURRENT" CONCEPT

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

 

Because most book and textbook authors believe ...that Electricity is the 
flow of Electricity.  (What?)  They think that "Electricity" appears 
whenever Electricity flows in wires?  That whenever Electricity starts 
flowing, this flow is called by the name Electricity?  Yep.  Or put more 
simply, authors themselves have little grasp of the difference between 
amperes and coulombs; between current and charge.   They talk as if 
electricity is a thing that flows inside of wires, then they turn around 
and say that electricity is the flow of something else inside of wires.
It's as bad as being confused about the difference between air and wind,
or the difference between the flow of river water versus the water itself.
(Is electricity something like water, or is it something like the flowing 
motion of water?  Look in K-12 textbooks.  You'll never pin them down to 
one clear position, instead they switch back and forth.)

It's impossible to grasp because books continuously state that "current 
flows."  (This is connected to the mistake above.)  If an author tells us 
that "current" is a stuff that flows along, then this tends to convince us 
that a substance-like entity called "current" exists.  And it wrenches us 
away from any use of the Charge-flow concept.  (Physicists know that 
electric current is a flow of charge, but read K-12 textbooks and see what 
language they use:  not "charges flow," but instead "flow of current.")  
We can easily test for this mistake in any book or piece of written text.  
Just mentally replace their word "current" with the phrase "charge-flow" 
to see how it reads.  Most explanations will then wrongly teach that 
"charge flow flows," and they'll speak of "flows of charge flow."  Some 
books even say that an electron is a tiny piece of "charge flow."  (No, 
electrons are particles/carriers of charge, not carriers of "flow.")


...mistaken belief that generators and batteries send out a "substance" or 
"stuff" called "current" to appliances.  (In reality, electric current is 
a flow of the copper's own charges.  Currents are not like a substance 
which can move.)  This error is connected to the mistaken belief that 
there is no path for current THROUGH a battery or generator, so that the 
"current-stuff" can only be supplied by the battery. (In reality the 
charges do flow *through* the battery and back out again. If the flow-path 
did not go through the battery or generator, then that would constitute an 
'open circuit,' and all currents in that circuit would cease.)


It's impossible to grasp because of the mistaken belief that, since 
batteries and generators CAUSE electric currents, they must be PRODUCING a 
substance-like material called "current."  Or, since batteries and 
generators cause a flow of "electricity," we wrongly assume that they must 
be CREATING an electricity-stuff.  In fact, the flowing charges were 
already in the wires to begin with, and batteries/generators simply behave 
as charge-pump devices.   If electricity is like the rubber of a drive 
belt, then batteries and generators are like the drive-wheel which makes 
the belt move in circular fashion.


It's impossible to grasp because of the wide use of a confusing phrase 
"amount of current."  No, current is actually a rate, not a substance-like 
quantity.  Instead we should be careful to say it this way: "what's the 
rate of current," or "intensity of current", or "what is the value of 
current."


It's impossible to grasp because early textbooks wrongly mix the concept 
"quantity of a substance" with concept of "flow rate of a substance."  
This mistake occurs not only in electricity.  Does a shower use lots of 
water?  Meaningless question, since the length of time is not given.  Or, 
is a high current actually a flow of "lots of electricity?"  Meaningless, 
since it's the amount electricity flowing PER SECOND, not just electricity 
flow.  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.


It's impossible to grasp because of incorrectly stating that electric 
current is the "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!


It's impossible to grasp because of the mistaken belief that devices which 
cause currents must be the sources of the flowing charge.  (No, it's the 
wires which supply the charge which flows.)  Mistaken belief that 
generators "supply current" (i.e. charges)  rather than simply pumping 
them.  This idea is supported everywhere by the incorrect terms "source of 
current" and "current carriers," which should more clearly be written as 
"cause of current" and "charge carriers."

It's impossible to grasp because of taking electric current as a 
fundamental entity, when charge is actually the fundamental entity (maybe 
done because of the N.I.S.T. ampere-seconds physical standard.)  This 
wrongly diverts us from exploring deeper concepts involving electric 
current as flow of electric charge.

It's impossible to grasp because of mistaking the high-speed chaotic 
vibration of electrons for the low-speed motion during electric currents.  
(analogy: learning that air molecules individually move very fast, and 
then wrongly concluding that the earth must experience constant hurricane 
winds.)  In fact, high speed air molecules imply HOT air.  But the hot air 
is unmoving.  And the high speed of electrons in metals acts like thermal 
vibrations; like heat in the metal object, and is not an overall motion or 
electrical current.

It's impossible to grasp because of the mistaken belief that all electric 
currents are flows of electrons.  They aren't.  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.  In a battery, since only charged atoms are flowing between 
the plates, and since no electrons flow there, we may end up thinking that 
the path of electric current cannot be THROUGH the battery.  In fact the 
path is through the battery.  This "electrons are electricity"  
misconception destroys the whole concept of "electric circuits", since we 
mistakenly assume that batteries are open circuits.  Wrong!  A battery is 
a closed circuit, because if it was like an open switch, 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.  Circuits can be built 
using saltwater hoses full of flowing atoms.  If one believes that only 
electrons are important, or that protons and ions can never flow, then one 
may mistakenly believe that the strangely enlarged quantum-mechanical 
behavior of the low-mass electrons proves that *all* currents and 
quantities of charge are weird and Quantum-y.  In reality, 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 the classical 
views of physics.  But ion-based electric currents are very common 
phenomena in everyday circuits, and ions are massive enough that their 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, therefore 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 must flow around and around a circuit, 
passing THROUGH the battery over and over. 

...educators never employ the convenient fact that the rate of charge flow 
is proportional to charge speed within a particular wire.  This greatly 
clarifies electric circuit concepts.  High current is FAST charges.  Zero 
current is STOPPED charges.

...wrongly 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, and 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 ^

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 substance-like 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 viewing 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 canceled
charge (current) is unmoving canceled 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
visualizeable.  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 "canceled charge."  When + and - come
together, the result is NOT nothing.  The result is matter.  The result
can also be the canceled-but-mobile "electric fluid" found in all
conductors.  Since matter contains (is even MADE of) "canceled charge," 
and since electric current in wires is a flow of "canceled 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
	canceled 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-visualizeable. 

...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 canceled, 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 canceled 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 canceled 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
canceled-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

   Large list of refs on Electricity Misconceptions:
        http://amasci.com/miscon/electref.html

   List of books on misconceptions:
        http://amasci.com/miscon/books.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


 
          




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