Well, maybe. But when you picture in your mind's eye the weight of a soft drink can, do you do it as an empty can or as a full one? I generally think of cans as

Well, maybe. But when you picture in your mind's eye the weight of a soft drink can, do you do it as an empty can or as a full one? I generally think of cans as full, not as empty. It's just a qualitative comparison dressed up as a quantitative one. I don't think it's all that misleading - it's just "Wow! That's a lot of aluminium!"