Asolid aluminum cube has sides each of length l . a second cube of the same material has sides two times the length of the first cube; i. e., 2 l . compared to the first cube, what is the density of the second cube?

Density is a property of the substance, no matter how much of it you have. A microscopic speck of it and a truckload of the same stuff have the same density.

Honestly "global warming" may be a slight possiblity, however they called it "climate change" because its not real, in fact we had one of our coldest days here not too long ago, and the "issues" with this subject is a blindfold for actual problems.