Arduino board : difference between two gnd port

Question

On Arduino board, I see two port gnd : one in power line (a list of port has power label beside), that I call gnd(1). And the one is on the other (the line that has port from 0 --> 13 and gnd), that I call gnd(2).

I don't know the difference between two port, but when I test a LED on breadboard, if one line I connect to gnd(1), the LED will be lighter than gnd(2) (gnd(2) just has a small red light)

Please explain for me the difference.

Thanks :)

Answer 1

From reading this page: http://arduino.cc/en/Main/ArduinoBoardUno/ (if this is your board) I can't see that it should be any difference in your gnd ports. Maybe you provide different amount of power? Or do you have too much resistance at one time?

I have used Arduino pretty much and I've never had your issue even if I am using all gnd ports available.