Hi, I'm working on a project and would like some help regarding heat transfer and heat conductivity. Any help would be appreciated, I'm more or less a layman. If I wanted to use heat from the sun to heat water via a metal conductor, does the size of the heat sink have proportional heating capacity? For example, would a copper square measuring one square meter get significantly hotter then a copper square measuring one square foot, due to the increased surface area, and thus more heat radiation collects in the metal? IF so, would that increase proportionally? Would a copper square measuring one square mile increase in temperature in proportion to it's size (I assume at least until it reached the melting point of copper)? second part, I understand heat conductivity, but what is heating capacity, as it relates to heat transfer? Copper is more conductive then aluminum, but aluminum has a higher heating capacity. Which would be the best metal to choose if I wanted to transfer heat from the sun, to a liquid? And would the thickness of the metal heat sink make a difference? I.e. would a copper square measuring one square meter and 1/4" thick transfer more heat then a copper square measuring one square meter and 1" thick? Any help would be greatly appreciated.