The lights lit up. It was amazing. Luckily I caught it on camera.

[wpvideo 3qSfZelv]

Going back over this lab, I was trying to figure out how the circuit works. I read that electrons actually flow from ground to power, despite the conception that current flows toward ground. So I was trying to visualize the part that confuses me: Why the circuit is not a simple loop, interrupted by a switch. Instead the current seems to have two parts, bridged by the 10K resistor.  This is the circuit that would make sense to me,

and here is the way I think I would draw the actual circuit.

I think this is parallel, and the one I imagined is series??? Also, I realize that the micro controller breaks up the circuit, has resistance, so maybe displaying it this way is meaningless, and maybe its completely separate circuits???

But I want to understand why the 10K resistor is necessary.

And it works without the 10K resistor, except for a delay when the switch is released: the LED remains on HIGH for several seconds. When I reinsert the 10K resistor with the ground leg first, the program works as intended. But when I inserted the switch-side leg of the resistor first, I noticed that the LED lit up when I touched the other leg. I don’t know what kind of circuit issue this is, but I was thinking that maybe that I conduct some electrons away from the resistor, and so the electrons are free to flow into the resistor until it fills up.

[wpvideo mIfN6XOH]