First of all, it would be good to know the definition of Cryogenic. Cryogenic simply means - dealing with temperatures -100 degree and lower. O2, N2, CO2, Helium, Argon and several other natural gases can be converted to a cryogenic liquid for example: the Temperature at which Oxygen turns into liquid form is negative 297.31 degrees F (it's boiling point) at atmospheric pressure (14.6 psi) at sea level. Raise the pressure and you raise the boiling point (for instance, water can boil at 140 degrees F, if under a vacuum, 29.95 inHg (perfect vacuum), while at atmospheric pressure it boils at 212 degrees F. Nitrogen, however is negative 320.5 at atmospheric pressure and at sea level, while Helium (the coldest gas in the world) is negative 505 degrees F. (that's' why you talk funny when you inhale a helium balloon; it's so cold, it brings your vocal cords closer together to make you talk at a higher pitch). Heat expands, while Cold contracts.
To my knowledge, helium only exists outside the earths atmosphere, although it is very abundant, making it into a liquid is not very cost effective due to it's gassing off in storage. So, N2 would be a better choice for Cryogenic Freezing.
Liquid N2 is also a safer cryogenic liquid to use than say O2 because 1) it is one of the coldest compared to other cryogenic liquids that are easily obtainable and 2) it is inert (meaning it contains less than 3% oxygen, whereas O2 itself, is 99.5 percent pure oxygen and highly supports a flame. N2 does not.) At 99.5 percent O2, a cigarette will burn like a dynamite fuse. Remember, oxygen doesn't burn, it just supports a flame. Yes, it can explode with an expansion rate of 1 cu.ft. of liquid oxygen to 12,000 cu.ft. of gaseous oxygen, but it does not burn itself without fuel (anything that will burn) and heat, the well known fire triangle (O2, fuel, heat).
Now, being that our bodies need oxygenated blood to sustain our lives, O2 might be scientifically the way to go on freezing human bodies, whereas N2 causes asphyxiation; BUT I don't think anyone will be breathing while frozen, so, liquid O2 very well could be the supplement of breathing, to keep the body alive, yet frozen, yet without feeling any pain (if there was a way to prevent it). Hmmm, tough to test on humans because someone would have to be a guinea pig. After one is already dead, then very little reason to freeze them except for research purposes maybe, but then again, there is the big "Religious, Moral, and Humane Factors" that are involved to prevent humans from being frozen at the moment.
On a religious point of view, the human body has a soul or spirit that causes us to be alive. So, the question remains, if the human body is frozen, then does it also freeze the soul, and if not, then how can it be revived without it? Some believe that when you die your soul leaves the body, so it brings us to the question of "If we freeze a human body before it dies? Is it still alive and just frozen in time? Once the soul leaves, does it come back? etc. etc." There are many factors and unproven theories involved in freezing humans. There is almost always the scientific approach versus the religious/spiritual approach, so, what do we know of the effects of putting a body in a cryogenic stasis? Well, not enough in my opinion.
On a scientific standpoint, scientist have frozen coach roaches and brought them back to life, but there again is the religious factor. Do coach roaches have souls? If not, then that my explain why they can revive them. The bible mentions that "God breathed into man the breath of life and man became a living soul." He never said that about anything other creatures or animals, so, to say a dog for instance, has a soul, would be preposterous to a man of the cloth. Others would beg to differ and say "Just look into a dog's eyes and tell me he doesn't have a soul?" Some love animals more that humans, but that's another story. Anyway, there are many resources on cryogenic research on the web and the human freezing subject, I just thought I'd give you something to think about from someone who has studied both religion and cryogenics.
Sum: Normally, when an organism is exposed to below-freezing temperatures, ice forms in smaller blood vessels and either bursts the blood vessels or stretches them beyond the point where they can function normally. In addition, ice in the blood vessels "captures" the water content, making it impossible for the blood cells to survive.
Good Luck on your science project!
Former Cryogenic Production Techinician for the US Navy
Former Ordained Pastor and Licensed Minister
Two Majors - Theology and Engineering
· 9 years ago