Quote of the Day
I understand that sometimes you have to win ugly, but I see no advantage in losing ugly.
— Pat Buchanan, political commentator.
I do not watch many movies and the ones I do see tend to be older. Over the Christmas holiday, I watched the movie "Men of Honor" and I noticed that Boyle's law was mentioned. Here is the Boyle's law quote from the movie:
Boyle's Law describes the behavior of gases under varying amounts of atmospheric pressure. It states that if a diver holds his breath at one hundred feet, continues holding while rising to ten feet, then the gases in his lungs increase four times. Now why is this important to a diver? Forget to exhale on the way up, and your lungs explode.
I heard the quote and I did a quick calculation in my head. It seemed like this statement was not quite correct.
After the movie, I did a more serious calculation. Figure 1 shows my work. My answer was that the lung volume will increase by a factor of three, not four. I know I am being picky, but it seems like the movie folks could get a a little detail like this correct.
Figure 1: Boyle's Law Calculations.
Many thanks to the Curious ChemEng for looking at my work. I could not believe the movie got this wrong and I asked him to check me. He also suggested a plausible way they got the wrong answer.
At least the explanation in the movie was within the realm of reality, even if the details weren't quite right. It's not as if they tried to claim that explosions in space make a sound, or something similarly impossible.
You are right. I am being nit picky. It just bugs me.
Mathscinotes
Nothing wrong with being nitpicky... it would be nice if movie people were too.
They Say 100 feet to 10 feet which is about 30 meters...now Pressure builds up for every 10 meters you descend...that is from 0 to 10 meters is 1+1 bar(cause you have 1 bar at 0 meters at the surface...) and for every 10 meters after this is another +1 bar...so at 30 meters you now have 4 bars of pressure which reduces the air in your lunge to 1/4...logically if you now rise from 30 meters to 0 meters withtout letting out air you now will increase your volume to 4 times that of 30 meters...this is because your lung gets smaller and can therefor hold less air...so at 30 meters your langs are so small by the pressure that They can only hold 1/4 of the air at surface ( 0 meters)....
Finally the ratio of the dive and the descend in the movie is the same...from 100 feet to 10 feet is 90 feet which is 30 meters and therefor correct....your lungs gets 4 times bigger and you Explode if you dont exhale on your way up...
maybe they wrote it that way because it is better to be save than sorry
Maybe! When I was certified it was 60 feet 60 minutes no decompression dive tables. It’s been changed to 50 feet for 60 mins. Most likely for safety.