Physics of diving question...

[DetectorGuy]

Thanks to all of you for clearing this up. I had been reading and reading until my mind was numb. When I got to that point things did not seem to make sense. I thought I was missing something. I am glad to hear all of your responses. I never took any physics classes in school and I pretty much just goofed around all the time.

The class is dive master. I am not taking it to lead tourists on dives in the pristine waters of Square Lake or to eventually become an instructor. With the help of some peer pressure from a friend of mine (if he doesn't mind me calling myself one of his peers). I am taking the class only to build my knowledge base about diving. The class hasn't started yet but he gave me the crew pack and I thought I would get a head start with independently studying prior to the first class to make it easier him and me too.

I learned some very interesting things already... argon... I posted in here a while ago called "how popular is argon" Since reading the manual I have learned that deep divers that use Heliox or trimix, tend to use Argon for suit inflation because helium for suit inflation would not work as it conducts heat much faster than oxygen or nitrogen. Also using helium in the suit would cause decompression problems because it diffuses rapidly. During decompression it can dissolve into the body through the skin faster than other dissolved gasses  (like nitrogen) in the tissues can dissolve out through the lungs. This is called isobaric counterdiffusion, and can occur when a diver breathes a slowly diffusing gas while surrounded by a rapidly diffusing gas. It can also occur if you breathe a rapidly diffusing gas while decompressing a slowly diffusing gas.

This is where the slight contradiction in using argon for suit inflation comes into play... Argon is very dense so Isobaric counterdiffusion is not a problem, but there has not been a ton of scientific testing of decompressing surrounded by a heavy gas while breathing a lighter gas. There are no theoretical concerns because no one important cared enough to study its effects. Still divers use argon in their suits for inflation, and have for years, with no widespread problems reported. This would be a good Thesis for some college student. If anyone comes up with a theory for this, I want to call it "The sober Irishmans theory".

Another thing I learned is that the USA is the main commercial supplier of helium. Some say that heluim sources will be depleted within this century. What will shore up the helium needs then you say? Possibly Neon. Neon is a rare gas on earth accounting for less than .002% of the atmosphere. Although it can be extracted from air using a freezing process to create "helioneon" (25%He, 75%Ne). It is thought to be the fourth most abundant element in the universe. Now it the space shuttle could just bring back a cargo bay load every trip back we would be set.

I thought all of that was interesting.