I opened the case to my XBOX 360 to dust the inside and noticed a copper tube what is that for?
It's part of the cooling system.
That copper tube is the heat pipe for the heat sink. The heat pipe transfers heat from 2 solid interfaces. In this case, the heat CPU creates is tranferred to the heatsink. Because hot air is less dense than cold air, the fan in the 360 forces the hot air out of the back. Lol sorry if i gave a longer answer than what you needed. Just answering the question in as much detail as I can.
