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Why is electricity so hard to understand? (1989)

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Re: Why is electricity so hard to understand? (1989)

#201

Post by [deleted] »

CamperBob2 wrote: post #127
gugagore wrote: post #123

Earlier quoted context omitted.

I didn't agree with what you wrote and maybe I can explain why. Springs store inches. You measure displacement in inches. Spring constant is just the value that relates stored inches to available force. (You can swap roles of force and displacement if you wish, the point is the same. It sounds bad to say springs store force or displacement, to me.)

But inches are an abstract measurement of distance. Electrons are a thing. (Well, depending on who you ask... no one has ever seen one, and some people have claimed half-jokingly there's only one electron in the entire universe: https://en.wikipedia.org/wiki/One-electron_universe .)

[deleted]

Re: Why is electricity so hard to understand? (1989)

#202

Post by pitaj »

bandrami wrote: post #117
pitaj wrote: post #107

Earlier quoted context omitted.

Ehhhhh. Not really. It is the rate of charge passing through a cross-section. That's how it's defined, and as an EE student, what you're saying made little-to-no sense to me.

And the boson that mediates "charge" is....?

Photons don't mediate charge. The mediate the electric and magnetic fields.

Re: Why is electricity so hard to understand? (1989)

#204

Post by dom0 »

andars wrote: post #174
dom0 wrote: post #147

Earlier quoted context omitted.

+1 It took me a huge amount of time to get rid of all the BS learned in school. In some area I'm even still working on it (eg. analysis).

When you say analysis, do you mean you are working on unlearning the stuff you learned in it, or learning it to replace something else?

unlearning mostly.

Re: Why is electricity so hard to understand? (1989)

#206

Post by bandrami »

wbeaty wrote: post #171
bandrami wrote: post #86

Earlier quoted context omitted.

Intuitive but wrong (and doggedly persistent) idea #1: "electric current is moving electrons". It is moving photons, exciting (largely) stationary electrons. I can't stress how crucial overcoming that misconception was when I was doing EE.

Actually, it's electric wattage which is the moving photons, not electric current. Energy flow. Joules per second, same as with laser outputs. So, the electric companies are selling us 60Hz photons. But at the same time, the AC electricity just vibrates back and forth inside the wires, without any net forward motion. About the only accurate diagram of EM spectrum I've ever encountered was the one made by R. Oppenheim…

I remember that poster! I actually got a copy from the Exploratorium...

Re: Why is electricity so hard to understand? (1989)

#207

Post by Aardwolf »

wbeaty wrote: post #183
Aardwolf wrote: post #3

Dear author of the website: Nice article. Please fix the TOC links on "whyhard2.html" to point to "whyhard2.html" and not to "whyhard1.html", and remove the huge whitespace between TOC and content. This was a very confusing experience and likely others will fall in this trap. Thanks!

DOH! Fixed now. I messed it up last time I was getting slashdotted by reddit and ycombinator, and everyone was complaining that the raw unedited notes were just a bunch of raw unedited notes. Heh, it's still a 1995 gopher-era design, back when we put all our chapters on a single long page, to compensate for 300/2400b modem speeds. If it was broken up into many separate pages, you'd be waaaaaaiting for the text to fin…

Thank you very much :)

Re: Why is electricity so hard to understand? (1989)

#208

Post by wbeaty »

lisivka wrote: post #198
wbeaty wrote: post #165

Earlier quoted context omitted.

Hydrogen gas is insulating matter. Ionized hydrogen is conductive matter. Too bad we don't have metallic hydrogen. It would be a solid conductor, just like any other metal. "Conductor" actually means "contains mobile charges." Conductor doesn't mean "a hollow pipe which electricity flows through." Conductors are more like long, narrow ponds. They're made of 'electric fluid,' so if we have a ring-shaped pond, we can p…

We have: On October 5th 2016, Ranga Dias and Isaac F. Silvera of Lyman Laboratory of Physics, Harvard University released the first experimental evidence that solid metallic hydrogen has been synthesized in the laboratory. It took 495 GPa pressure to create. The sample is being held in the cryostat in liquid nitrogen.

Cool!

They can then check the possibility that, once formed, it remains stable at low pressure.

Re: Why is electricity so hard to understand? (1989)

#209

Post by pitaj »

bandrami wrote: post #205
pitaj wrote: post #202

Earlier quoted context omitted.

Photons don't mediate charge. The mediate the electric and magnetic fields.

And the field that is quantified as "charge" is...?

An electron? I don't know what you're getting at here. An electrostatic field is produced with strength in proportion to the charge. However, that is not the only way an electric field can exist. For instance, they can be produced by changing magnetic fields, and when these two fields interact in a way that they mutually generate one another, that's what we call an electromagnetic wave, or "photon." Photons don't mediate charge, they simply are the carrier for the information of a changing electric or magnetic field.

It seems like you have a fundamental misunderstanding of how photons are produced, or what they do. At least in DC conditions, no photons are produced at all (since there is no changing magnetic or electric field), yet there is still current.

Current is the movement of charge. Photons are irrelevant, besides being the messengers for the electric and magnetic fields, which still only applies if those fields are changing, as no information is changed otherwise, so no bozon is necessary.

What you may be thinking of is in an AC case, where current is constantly changing as the electric field wave propagates down the transmission line. This does necessitate photons. But even then, the current is still the flow of charge, and oscillates between negative and positive.

Re: Why is electricity so hard to understand? (1989)

#210

Post by lawpoop »

wolfgke wrote: post #13
lawpoop wrote: post #12

I think the main reason is that we can't physically interact with it with our hands. We don't play with it as children, the same way we do running water, throwing rocks, etc. Anything that you can't manipulate or play around with is very hard to develop an intuitive sense of. It takes a lot of study and imagination.

> We don't play with it as children, the same way we do running water Navier-Stokes equations are not easy to understand.

That's true, but people have been swimming, boating, and sailing for thousands of years before those equations were invented. We can develop an intuitive sense for that, because we have direct and visible interaction with those fluids.
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