Proving That Copper Is Cooler Than Room Temp

[j-rock]

I'm looking for a good article or string that would help me win a bet with a friend that is occasionally accurate...but not on this. Does anyone have any advice as to how to prove that I'm the winner of this bet? The bet is based upon a discussion as to why my brand new liquid-cooled heat sink (copper tube under a CPU fan) felt colder than room temperature even though it had never even been installed or powered up the first time. Embarrassed for him, I pointed out that it's obviously because of the properties of the metal itself...just like glass at room temperature feels cooler than something like wood in the same room. He argued that it's because the gas in the tube is cooler than room temperature, making the copper tube cold. Embarrassed for him again, I told him that it's physically impossible for anything to be cooler than room temperature without a physical change or chemical change causing the temp change. He continued to damage my limited respect for his intellect by pointing out that propane tanks are cold even when not being used. I have looked for something that proves him wrong at a level of understanding that will convince him. Any suggestions?

 

[Sakha]

Take a look at this similar thread.
https://www.physicsforums.com/showthread.php?t=423839"

 

[AudioFlux]

sooner or later all non-living things that in contact with the atmosphere will have the same temperature as the atmosphere, as they will decipate or attain heat (small plus, minus of heat) with the atmosphere...but when we are exposed to the same temperature for some time, our temperature becomes a little less than the temperature of the atmosphere because of the combustion reactions taking place in our bodies. so if we touch anything that is in contact with the atmosphere, we'll find it cold. the only reason why we don't feel as cold by feeling the atmosphere as touching any other non-living thing is because we decipate energy more quickly to solids or liquids than gas.