

How electricity doesn't work - xbryanx
http://amasci.com/miscon/elect.html

======
derefr
Disregarding the content of this work (the author's conception of electricity,
or lack thereof), I found this passage in the preface to be striking:

> After my encounter with those books, I slowly realized that my own
> understanding of basic electricity was flawed and incomplete. I sat down and
> started re-teaching myself the subject. I became aware of the source of my
> problem: I myself had learned a bunch of electricity misconceptions as a
> child. Those early misconceptions gave me a faulty foundation on which to
> build further knowledge. As a result, any accurate information learned later
> became distorted in my mind even as I learned it. If the foundation is
> distorted, then the "building" cannot be built. It was like trying to build
> a brick wall on top of a garbage pile: the incoming bricks are perfectly
> good, but they simply did not fit upon earlier concepts, and any structures
> that I managed to build kept collapsing.

Many of the textbooks he was reading through (K-6 level books) were using the
pedagogical technique of <http://en.wikipedia.org/wiki/Lie-to-children> ,
where one purposefully gives inaccurate-but-simple information, planning to
supplant it later with more accurate accounts once a foundational knowledge of
the terms and laws of the system have been built within the student's mind.
Both the misconceptions he is addressing, and his own misconceptions, show
that this technique is more dangerous than it is believed to be, because
_people keep these inaccurate accounts_ , resisting learning the more complex
but real accounts due to some bastardized version of Occam's razor.

~~~
lutorm
I'm not sure what you are arguing here. What would a world look like without
simplification? You want people to remain in complete ignorance until they are
judged at some point to be "ready" to learn the complete truth about
something? That seems like an absurd viewpoint to me.

Besides, your comment ignores the fact that people, in the absence of
explanations (right or wrong) will _make up their own model of how things
work_. That model is just as hard to unlearn as an incorrect view they may
have been taught by an instructor. In fact, they are probably harder to
unlearn because they are based on the persons own experiences.

 _All_ learning involves correcting and building on earlier concepts, there
are no " _tabula rasa_ ". What is important is that people confront and
integrate their own preconceptions as part of learning.

The National Academies Press book "How People Learn: Brain, Mind, Experience,
and School" is a good, accessible introduction to these concepts. It's on the
web at <http://www.nap.edu/html/howpeople1/>.

This is a relevant passage: "A logical extension of the view that new
knowledge must be constructed from existing knowledge is that teachers need to
pay attention to the incomplete understandings, the false beliefs, and the
naive renditions of concepts that learners bring with them to a given subject.
Teachers then need to build on these ideas in ways that help each student
achieve a more mature understanding. If students' initial ideas and beliefs
are ignored, the understandings that they develop can be very different from
what the teacher intends."

~~~
derefr
I'm _not_ arguing that we should not simplify instruction at lower levels; I'm
simply arguing that there are ways to simplify without creating _inaccuracies_
: to avoid using leaky analogies, for instance.

------
kurtosis
This is quite discouraging to read - the author sets out to correct many
common misconceptions but ends up introducing many more - (e.g. electrons
don't "hop" from atom to atom (there are some quite useful models of metals
based on hopping), metals bend because electrons "fill in" the gaps)

Reading this reminds me of the importance of mathematics for placing a hard
edge on vague and potentially confusing terms like "flow" "current" "energy"
"store" etc. etc.

I wonder if it is possible to give 6th graders correct intuition about
electricity without math?

~~~
onoj
Are the models of metals /hopping you are referring to involving free outer
electrons in a metal crystal lattice - as he was referring to?

~~~
kurtosis
Yeah - especially metals like Fe, Co, and Ni where the conduction electrons
are derived from the atom's d-orbitals. The hopping is one of the key elements
of the "hubbard" model. This viewpoint doesn't add very much if you want to
calculate the conductivity or optical properties, but it is essential for
understanding the magnetism of these materials.

What bugged me about this article was that without doing a quantitative
analysis of a model and comparing it's predictions to experiments - physical
interpretations like whether the electrons are hopping or not are so ambiguous
that they are effectively meaningless.

------
Dunearhp
He confuses his own internal mental model with the actual nature of
electricity.

Mostly this is just arguments about semantics.

------
RK
With something like this it's hard to tell if the author is "dumbing it down"
or just doesn't understand the material all that well. He does style himself
an "amateur physicist".

------
tbrownaw
Really that entire site is wonderful, and quite varied. But note that it's
largely _not_ solid reference material (aside from perhaps portions of the
electricity stuff), it's more fun and interesting things to play with / think
about, that often require some knowledge of science to understand or make work
or show why they can't work. And a little bit of crackpottery, some of which
is even explicitly labeled as such.

------
petercooper
As with electricity, the average person is also taught how fixed wings provide
lift incorrectly:
[http://en.wikipedia.org/wiki/Lift_(force)#.22Popular.22_expl...](http://en.wikipedia.org/wiki/Lift_\(force\)#.22Popular.22_explanation_based_on_equal_transit-
time) \- I've come across plenty of smart people (though with no formal
physics knowledge) who blindly believed the transit time theory.

------
Daniel_Newby
Not accurate. Among many problems, when electrons move, they _do_ tend to move
near the speed of light. (The low rest mass means that even tiny amounts of
kinetic energy really get them zooming along.) However in Ohmic conductors
they frequently crash into scatterers, bouncing off at a random angle and
imparting heat to the material. In everyday materials like copper at room
temperature, they spend so much time bouncing around that the _average_
velocity of a conduction electron is low.

EDIT: If you want to teach electricity, describe it as a fluid acted on by
fast-moving pressure waves. Resistance can be reasonably described by analogy
to a viscous fluid flowing through a sponge.

~~~
Confusion
I figured he was going to explain how (free) electrons (at room temperature,
in a metal) actually move around at around 0.5c, but alas.

