Re: lay questions: "electricity" vs. EM spectrum
- From: Benj <bjacoby@xxxxxxxxxxx>
- Date: Fri, 20 Feb 2009 23:15:32 -0800 (PST)
On Feb 20, 10:26 am, leoboiko <leobo...@xxxxxxxxx> wrote:
I’m a layman who’s been reading the “electricity misconceptions” pages
from William Beaty and things make a lot more sense now. However, I
still have some questions, so I thought I’d ask you guys :)
From what I understood from the material, there are basically two
different things called “electricity”:
- Electric charge, which is made of electrons, is visible, has mass,
moves slowly, and is measured in coulumbs and amperes;
- And electric energy, which is “made of” photons, is invisible, has no
mass, moves at light speed (or near), and is measured in joules and
watts.
This idea is basically wrong. This is going to be a big problem for
you because as a layman you'll find it all confusing because the
"experts" also haven't a clue! Start here: Maxwell noted that
fundamentally there is only two ways to send energy through space. One
is by kinetic energy which means particles of matter with a
trajectory. Generally speaking electricity which is to say a flow of
charge falls into this category. The other way is by shipping the
energy by means of waves. Light, radio waves, X-rays etc all were
thought to fall into this category. Simple.
Only it's NOT simple! Modern physical theory asserts that there is NO
medium in "empty" space. This theorized medium used to be called the
"luminiferous (light-bearing) aether". Modern physics asserts that
light, radio, etc. all travel though "empty space" without benefit of
a medium. Hence such energy is NOT waves! And indeed by experiment
such a thing is found to be true! If you take a beam of light and
reduce the intensity of it, and then reduce it some more and then more
and more, eventually you reach a point where what you thought was
"waves" in a medium that diffract and focus and interfere and have all
manner of "wave properties" turns out to be nothing more than
individual particles zipping through empty space! Oddly, if you add up
all the trajectories you get statistical distributions of the
particles that follow wave solutions. Nobody knows why. These
particles are called "photons". Go look in Wikipedia under "double
slit diffraction" and there are some excellent pictures of how this
works. To distinguish between this and the "other" kind of
electricity, namely the flow of charge, we'll call that "electricity"
and this "electromagnetic energy".
My questions are about electric energy.
1. Why “made of” photons has quotes? Can I just say electric energy is
made of photons, quoteless, and be factually correct?
See above. Electromagnetic energy IS made up of what we call photons.
We put it in quotes because nobody knows exactly what this is or how
it works. Electricity is NOT made up of a flow of photons!
2. From what I could muster electric energy is *exactly* the same as
electromagnetic fields, right? So “electricity” (energy) is the
same as light, radio, microwaves &c. I find that surprising and
amazing and confusing:
Confusing because it's dead wrong. A flow of photons (which are
uncharged) is NOT the same as a flow of electrons which ARE charged.
Two different things. Although BOTH situations transmit energy. Hey, a
punch in the jaw also transmits energy!
2a. If electric energy is the same as EM waves, why do they “look” so
different? Why can’t I broadcast electric energy wirelessly, with
antennas, and get rid of power cables? Why can’t I power my
walkman with radio waves instead of batteries?
Remember that electromagnetic waves only SEEM to be "waves" actually
they are a flow of charge-less, mass-less (or nearly so) particles.
And indeed you CAN power your Walkman with EM waves instead of
batteries if you know how. And all radio/TV stations broadcast energy
from their antennas. (Shades of Tesla...who invented Radio!) But you
can also power a Walkman by plugging an adapter into the electric
current in your walls.
2b. How exactly does the interaction between electric energy and
charge works? Why I must have moving charge to sustain the EM
fields? There’s an example of a fluorescent light waved next to
power lines to demonstrate how electric energy (=EM fields) lie
outside the cables; then why can’t I power an appliance just by
holding its power cable next to the connector?
You do NOT need moving charge to "sustain" an EM "field". However, EM
"fields" are created by accelerating charges! They are not created by
charges moving at constant velocity. And yes you CAN power SOME kind
of "appliance" by holding the power cable next to the connector. It's
just a question of the efficiency of the power transfer. Example: Some
electric tooth brushes charge wirelessly with no connection.
2c. How does electric energy relates to the EM spectrum? Wikipedia
currently says AC current is right there at (e.g.) 60Hz, which
makes sense. Why no one told me this before?! Why most spectrum
charts never mention “electricity” at all?
OK. Now that you know that there are two kinds of electrical energy,
consider the 60 Hz currents in your house. Can those "electric"
currents create an EM "wave" transmitting energy? Yes they can. The
waveform is a sine wave which means that there is acceleration of
charges which means that radiation IS possible. However at 60 Hz. the
frequency is so low that EXTREMELY long wires are needed create any
radiation efficiency. Of course power transmission lines ARE very
long! And if efficiency isn't the issue, note that one can use a stud
finder of a certain type to pick up the fields from wires in walls
with no connection to them. And now you know why EM charts never
mention "electricity". (Don't all answer at once!) Right. Because
"electricity" is a flow of charge and not an EM transmission of
energy!
And what about DC? I found a single source claiming its EM fields
lie at 0Hz. What does zero frequency even mean? What’s an EM
wave without, well, waves?
Obviously DC or even better "zero frequency" is a mathematical limit
which is of no practical relevance whatsoever! Of course modern
physicists who like to show how much "physics" they know by showing
what wonderful mathematicians they are will talk endlessly about such
non-physical cases as if they were real. They are NOT real. Zero
frequency implies infinite time periods etc. etc. Even DC is not
"zero frequency" but rather a pulse that is of a length of time from
when you turned it on until you turned it off.
Now the question of EM "waves" without waves is FAR more relevant and
serious! Just WHY do the statistics of photon trajectories follow the
mathematics of waves in a medium? There are probably only a couple of
reasonable answers. One might be that the aether deniers are wrong and
a medium does actually exist. (after all, "empty" space DOES have
"properties") Another might be that there is some kind of interaction
of photons and matter at a distance that we do not understand, but for
some reason has solutions to the equations of motion that are
identical to the equations describing wave theory in a medium. Nobody
has a viable theory for this yet, though a couple of interesting ideas
have even been put forth here!
There! Even though you are a layman, you are now about as smart as
the "experts" in this field on this subject.
As for me, I can't say any more because I've got to get back to
mopping floors at Burger King!
.
- References:
- lay questions: "electricity" vs. EM spectrum
- From: leoboiko
- lay questions: "electricity" vs. EM spectrum
- Prev by Date: Re: Is General Relativity a useful TOOL or aesthetic ART?
- Next by Date: Re: Simple experiments that conclusively disprove General Relativity
- Previous by thread: Re: lay questions: "electricity" vs. EM spectrum
- Next by thread: Some good news for those worried about climate change
- Index(es):
Relevant Pages
|
