which, again, would take more work and more air. To combat the pull of the air, Ethan would have to haul around a ton of iodine. The density of lead is more than double that, 11.34 g/cm 3. The density of the most dense non-metal is iodine, at 4.933 g/cm 3. Neither of these are options for Ethan, who can't have any metal on him. Generally, when you scuba dive, this is counteracted with the weight of your equipment (generally around 50 pounds) and additional lead weights, if necessary. And the more energy you expend underwater, the more air you need.* If Ethan had simply taken a plastic container of air down with him (despite likely only getting a couple of breaths), he'd spend a good amount of energy working to stay underwater, against the buoyancy of the air.

Part of the benefit of the solid metal - the standard steel tanks generally weigh 30-40 pounds - is that it usually helps counteract this buoyancy.

and if you do manage to get deep enough, watch it compress under the water pressure. As a test, take a capped, empty three liter soda bottle into a pool and try to stay submerged. imagine an over-filled balloon.Īt lower pressure levels, it's certainly possible that someone could create a heavy-duty plastic cylinder but many of the fittings on a regulator are also metal, at least in part, so you'd reduce the amount of metal by a huge amount but it still wouldn't be no metal. In order to hold that high-pressure air, it's necessary that the container be made of metal, otherwise it would explode. The first and second stage of the scuba regulator work to reduce the level of the pressure to the ambient level for the person using the air. In order to have sufficient air to breathe in underwater situations, the air is very highly pressurized (3000 psi on average).

Mission impossible 5 free