The thing is your body is pressurised to counteract the normal atmospheric pressure on earth.
If you are suddenly subject to a vacuum, say in space, this pressure will push outwards. Your skull might not explode, but your soft tissues will have problems.
This is called “explosive decompression.”
PosterChild, I also found it hard to believe that 30 feet of water has enough pressure to kill you. Here’s how it goes: The diving suits have an area of roughly 2 square meters. This is about 3050 square inches. For every 33 feet you go down (underwater), the pressure goes up by 1 atmosphere, or 14.7 pounds per square inch. At 30 feet, you have roughly 40,350 pounds of pressure exerted over your whole body (30/33 times 3050 times 14.7). If that pressure is balanced by an appropriate amount of pressure through your air hose, no problem. If something happens to the pump and there’s no pressure (above the normal sea level pressure that the end of the hose above the water would see), you have 40,350 pounds of pressure trying to squish the flexible suit and your body up into the rigid helmet. This makes quite a mess. It has happened to some unlucky people, and is quite thoroughly fatal.
**cite:**Principles and Practice of Occupational Medicine by Carl Zenz, second edition.
There are two things I don’t understand about that. I have a little trouble adding up the pressure per sq. inch to come up with the pressure “over your whole body.” Because it is the whole body, shouldn’t it “stay” divided over the surface area.
Now that I re-read it, I think I see what you’re saying. The rigid helmet prevents the pressure from being transmitted to its interior except through the neck opening. If the air pressure decreases (which shouldn’t happen if the air is blocked, but only if the pressure in the hose has “access” to surface pressure) then the pressure becomes lower in the helmet than around the body.
So, it’s not that 30 feet of water makes a person implode, but if you set up a differential at 30 feet with a rigid helmet you’ll get squished into the helmet.
By gosh, I think I’ve got it.
PC
Now THAT’S a story I’ve never heard before–the pushed-up-into-the-helmet story. Extremely bizarre . . . are you sure that’s not just some urban legend?
Now THAT’S a story I’ve never heard before–the pushed-up-into-the-helmet story. Extremely bizarre . . . are you sure that’s not just some urban legend?
Yeah, I know it sounds bizarre, but such a case is mentioned in the medical text I cited.
Yeah, I know it sounds bizarre, but it’s mentioned in the medical text I cited.
Yeah, I know it sounds bizarre, but it’s mentioned in the medical text I cited.
Yeah, I know it sounds bizarre, but it’s mentioned in the medical text I cited.
Imagine getting trapped in a huge pressurized gas tank, with just your head sticking out from a small hole. If you increase the pressure of the tank the pressure will squeeze your body out the small hole, with rather unpleasent consequences. It’d be the exact same situation if you have a diving helmet with much lower pressure than the surrounding water. In each case, the cause is not high pressure alone but the difference in pressure.
Arthur C. Clarke used the idea of people going through vacum without a spacesuit at least four times – The Other Side of the Sky, Earthlight and 2001: Space Odyssey. It as discussed in The Fountains of Paradise, and Clarke discused it in some of his science fact books, as well (The View from Serendip and The Lost Worlds o 2001, I believe, in which he justifies the scene n the movie where Bowman re-eners the Discoery without his helmet.). Other writers have used the idea, as well. Some of them, like Pierre Boule and martin Caidin (who should have known better) got it wrong, and have the body blowing up (in ** Five Came Back**). Clarke cites NASA stusies on monkeys and chimps.
I think Total Rcall and Outland and the James Bond movie icense to Kill had people exploding because it’s an interesting visual, and damn the inaccuracies.
Sorry for the multiple posts. Dang hamsters.tonbo0422, here are actual quotes form the text I cited, Principle and Practice of Occupational Medicine, second edition, chapter 25. Page 384: “Whole body squeeze can be a fatal complication of using the classic copper-helmeted deep-sea dress. If gas pressure in the helmet becomes less that the pressure surrounding the flexible dress, the entire body may be crushed and forced into the helmet.” Page 397:"As long as the pressure inside the diving rig equals the sea pressure without, no problem occurs, but should the diver fall from the surface to 10 feet without admitting more air to the rig a pressure of 4 tons will be exerted on the flexible portion of the rig, tending to drive the entire body into the helmet and breat plate. "(Note that this is less pressure than I calculated, but still vey large. “A serious squeeze will cause the whole body to be crushed. In ann accident reported in the East River at a depth of 30 feet, where the pressure in the helmet suddenly became equal with atmospheric pressure, the 12 tons of squeeze necessitated the diver’s remails being dug out of the helmet with a spoon (italics mine). Reportedly, in a similar accident following a fall off the bow of the Empress of Ireland in the Gulf of St. Lawrence, the diver was unable to reach his air supply in time and the softer parts of his body were found 12 feet up the aitline.” I know it sounds unbelievable, but these are direct quotes from the book.
Well, direct quotes with spelling errors. That should be breastplate, not breatplate, and airline, not aitline. Sorry.
Bumping to repeat my question –