Suppose I had two large containers with 1 cubic meter size. The containers are identical on the outside. The containers are floating in microgravity very close to my space ship.
One was empty but had thick reinforced steel walls so that its mass was 600 kg, while the other had thinner aluminum walls but was about half full, say 500 kg of water and 100 kg dry mass.
I have limited oxygen and need to quickly ascertain which container has water for my ship's solar-powered electrolysis system.
What kinds of tests could be done to cubes, to choose the one with the water? The containers are bulky but meant to be moved around by astronauts in microgravity, they have several hand-holds, in corners, sides, and faces, so I have flexibility in where I grab it.
The ship also has plenty of hand-holds on the outside, and cubes are floating roughly a meter away.
I first think that I can "slosh" it but then realized that I don't really have a good understanding what sloshing means in microgravity. It's not the same as on Earth where you know the liquid/air line is horizontal and the water is the "bottom". So, can I do sloshing test in microgravity for identification of containers?
Are there better ways to manipulate the two containers by using less force that would give me either visual or tactile clues as forces through the handles and my gloves to notice which one has the water?
Remember: I'm running out of oxygen, I want to be clever and not run out of oxygen before I can choose the right container to make more oxygen!