Those things are no joke. Two winters ago some friends of mine were making beer, and pumped water in from a garden hose that was buried in snow (so the water was just barely above freezing). The water that came out was almost boiling.
Water-->copper-->water will be more efficient that air-->copper-->water though. That's why we build radiators with fins rather than just sticking a fan on a coil of copper pipe.
If that was true, then heat pipes would not work either.
The inside is not smooth, it is porous like the wick of a candle. The wax of a hot, melted candle moves straight up, defying gravity, right?
What happens if you stick a napkin onto a spill? Will only the very bottom of the napkin become wet?
Edited by willis888 - 4/2/12 at 8:02pm