In simple words,

Explain the reciprocal formula.

And

Why adding resistors in parallel decreases the total resistance.

That's it.
Where are my friends?

just think of it like flowing water. a skinny pipe (high R) is more resistant than a fat pipe (low R). Of course, connect both the skinny pipe and fat pipe to the hose and you get the benefits of at least the fat pipe plus some extra flow from the skinny pipe.

A little to simple and didn't answer both question. Still donating 10fg though because it does confirm the answer I was working on about cross-sectional area.


Update.

I only need the reciprocal formula in simple words (but not too simple).

Your just calculating the reciprocal of the sum OF the reciprocal of each branch circuit.

A reciprocal is 1/x

So in this case, X would be the reciprocal of each circuit.

I'd type it out but I'm on my cell. Hope that makes sense.

E: ill try..

1
----------------- = Rt
1/r1+1/r2

This post was edited by ozzyarmy3 on Sep 30 2014 10:16am

In parallel there is same voltage across each resistor.
also the current adds

I = I_1+I_2+I_3+...
V/R=V/R_1 + V/R_2 + V/R_3 +....
Since the voltage is the same you can divide by it because of V=IR
1/R = 1/R_1 + 1/R_2 +1/R_3 +....

Both just reinstate with the mathematical formula. That's not an explanation, in words, what's happening.

Well, parallel circuits add more paths for the electrons to flow. With more paths, more electrons will flow and therefore current will increase
from V=IR you can see that with increased current resistance decreases

Yeah, I got that already. Just looking of an explanation in words the reciprocal formula.
To clarify, an explanation in words what the reciprocal formula is doing.

This post was edited by ROM on Sep 30 2014 11:14am

to answer your question of WHY the reciprocal is used, it's because of something called conductance. Conductance and resistance are INVERSELY related.

Resistors add RESISTANCE in series
Resistors add CONDUCTANCE in parallel

It's just a plain RULE to electric theory. You can make sense of it any way you want but that's a fundamental principle you should understand. G is the symbol for conductance and if you need to ask why the reciprocal formula is relevant after that, you might need to go back to your basic math rules.

This post was edited by PraizeAllah on Oct 2 2014 07:57am