MadSci Network: Chemistry |
Obviously, if some cans of sugared Coke sink, while others float, something is affecting the density of the "floaters". I can think of three possibilities, most of which seem unlikely given the rigorous quality control under which soft drink manufacturers operate. (1) Different amounts of sugar in a given can. (More sugar is denser. Sugared soft drinks should sink! A substantial difference from can to can seems unlikely, as this would imply very poor quality control and an inconsistent flavor.) (2) Different amounts of carbonation in a can. (Lack of carbonation would mean less mass in the can, thus lower density. Probably a very small difference.) (3) Different amounts of liquid in a can. (Less liquid means less mass, and the can could float.) Of these three factors, I would suspect the third. A small decrease in the volume of liquid in the can could cause a substantial change in total mass, and allow the can to float. You could check this by emptying a "sinker" and a "floater" into separate measuring cups (or graduated cylinders) and seeing if the volumes differ. Susan Rollinson
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