As we were just of the shelf of the South Orkneys we had quite a mass of water below the ship, over 5000 m of depth to be sorts of exactly. As the first night at this station didn’t involve deploying the RMT 25 we only had to help deploying the other gear. Just at the end of our shift a deep CTD would be deployed.
So it was time for a physics experiment. The duty mess was raided in search of polystyrene cups, the disposable cups you get hot beverages in. These cups were den clearly labeled and put into a bag. This bag was then attached to the CTD to make the trip below 5000 m. The results of the experiment were astounding.
As the depth increases by ten meters the pressure increases by one bar. This means that at about 5000 meters you have a pressure of 501 bar. While such an increase in pressure doesn’t affect solid materials (The CTD looked pretty much the same coming up) it does affect more compressible materials such as polystyrene cups. Anyhow, the before and after pictures should speak for themselves.