Do submariners ears pop?

Helen - No their ears probably don't pop because in fact, unlike a scuba diver who takes down a tank of air and breathes it at pressure that is equal to the water around them-which becomes very high very quickly as you go down-submarines are pressurised so that inside them they maintain the same pressure as air at the sea surface (1 atmosphere or atm: the unit we use to measure pressure). Whereas when you're scuba diving, you could be breathing air at something more like 20 atmospheres, which is much more dense. It's that pressure that makes your ears pop and you haven't got that in submarines. You may get a bit of compression as you're going down in a submarine as some of that pressure from the water is pushing in on the metal structure and the air inside. But I think that's fairly minor, I imagine. They build submarines fairly tough so that they can withstand all this pressure without collapsing inwards. So no, submariners don't have popping ears and interestingly and importantly, it means that if you have an accident, deep down and you have to escape from a submarine, you won't get the bends because you haven't been breathing air at pressure. You haven't filled up your system with nitrogen which will then bubble out of your blood if you're scuba diving and you come up too quickly. Same thing doesn't happen in the submariners. Submariners are trained to be able to hold their breath for long enough to swim a long, long way up from the bottom of the seabed to the surface and survive if there's a problem down below.