Okay so, I'm pretty new to programming with electronics and have a noobish question.
How does the below setup work? It obviously does, and I've done it along with numerous other Arduino configurations. I just don't get where the positive comes into play. How is there a full circuit here? What I see is a circuit between negative and pin 13, and positive never coming into play.
Also, I also may be misunderstanding negative versus ground. Can anybody point me in the direction of some good reading material? I have been doing some googling but haven't had any success. I've understood the basic breadboard and schematic tutorials/documents I've seen but there has to be something I'm missing here.
The positive lead is un used, perhaps for a later experiment. The 560 ohm resistor connects the "Positive" end (the Anode) to pin 13 on the Arduino and ground is the return path for the current sourced to pin 13 current for the LED.
Ground usually means the common voltage to which all others are referenced (compared). Typically you make things easy for yourself and call that 0V. Often ground will be connected to the enclosure, perhaps to mains ground (and thus to the earth itself), but this is required. Most (not all) circuits choose ground to be the same as the negative terminal of power supply or battery.
Physically you can't just have a single voltage - voltages (more correctly electric potentials) are arbitrary and only the difference in voltage between two signals is physically meaningful. Choosing one common ground for a whole circuit makes things simple.