[sdiy] Wanted: non mathematical description of the functionof RC-filters

[cheater00 .]

On Fri, Aug 9, 2013 at 11:05 AM, Florian Anwander
<fanwander at mnet-online.de> wrote:
> Am 09.08.2013 10:39, schrieb David G Dixon:
>
>> Why not just use that the mathematical equation
>> itself as the analogy.
>
> Did you read my comparison with sailing?

I hadn't seen that myself.

> There are moments in live, when you have to explain something to someone,
> where you cannot rely on your on explanation. Everyone who has children,
> will know that moments.
>
> (How would you explain a nine year old boy whith his model sail ship, how a
> sail is pulling the ship forward the fastest, though the wind is coming from
> 45 degrees from the front(!)? You can't use maths for that explanation at
> that moment.)

I cannot come up with a correct explanation that doesn't use momentum
and trigonometry. Rather than give an incorrect explanation, I'd use a
practical approach. I'd build a small model, and let the kid try out
different angles. Then, when he sees which angle is the best, his
interest will be extinguished. This is because he cannot yet ask more
complicated questions. He doesn't know what trigonometry is, so he
cannot formulate a query in its language. He's limited to simple
understanding.

I think there are many moments when it is impossible to give even a
simplified. For example, if the same child asked you why a transistor
is made out of silicon (he heard that on tv), what would you say? Or
if he asked you why radioactivity made you ill? Would you start
talking about valence points? In some situations you just have to say
"I can't explain it to you, but if it's still bothering you when
you're better skilled, you'll be able to learn it".

I don't know which one of those two ends of the spectrum better
applies to your RC filter "students". Bear in mind they're casual
readers. If they really truly wanted to read about RC filters, they'd
go out and get a book - rather than get surprised by the topic when
browsing a colour magazine while on the loo ;-) So maybe making the
"course" too long and to heavy is worse than making it short, tacit,
and letting off those who need to learn a few basic maths tricks?
Long-winded explanations are universally hated, difficult explanations
are only hated by people who don't understand them. If you have a long
explanation, even if the person reading it could follow it, they're
unlikely to.

D.