Four boxes of the same volume are each completely filled with one of the following items: sand, marbles, paperclips, or dice. The order of boxes from least to greatest mass is as follows: paperclips, dice, marbles, and sand.

Which box has the greatest density?

Marbles would have the greater density. Marbles would have the greater density because the molecules inside are more tightly packed. Even though sand has the greater mass it does not have the greater density. The sand doesn't have the greater density because it could be crushed in an instant, showing that if molecules are packed together tightly they will be tougher to break. The dice, I believe, still have a greater density than the sand.