Knowing the relative weight of things CAN be important.
I was working with animals at UCLA as a lab tech where we used carbon dioxide gas to euthanize small rodents.
One day we ran out of gas so I went downstairs to get some slabs of dry ice, frozen CO2. I was standing in the
elevator when the sucker stopped. There I stood, dry ice in hand, looking around the 6 x 6 foot freight elevator.
I was going to use the dry ice to put in a bucket with some mice. Snap the top on and the mice would be gone in 30 seconds.
Keerist! I was trapped in a small room with frozen dry ice turning into lethal CO2 gas. Then I remembered the gas was heavier
than air and just set the dry ice container on the floor. Saved this rodent!
BigSteve.