Work out which can has cooled the least. This can has the best insulation. Think about what you need to keep the same in this experiment. What else might affect how much the water cools down?

PRESENTER:'This is the Pearl River, 'and this is the great city of Guangzhou, 'what the Europeans call Canton. PRESENTER:And it was here, in the mid-1700s, that the destinies of China and the ...