the altitude, where the water begins to boil
Down here, at sea level, water boils at 100 °C. Since most of the gas molecules are attracted by gravity, this is where the highest atmospheric pressure is found. As a result, the air pressure is denser; expressed in value, this is roughly 101 kPa (kilopascal). This has no effect on our body because the air in our body exerts the same pressure outwards, so there is no pressure difference. As we move higher and higher, the air pressure is constantly decreasing, that is, the air is rarer and there is less oxygen. At this height – where there is a pressure of 6.35 kPa – , water begins to boil at 37 °C due to the low air pressure.
That is, at a temperature equal to the temperature of the human body.
In 1966, Jim LeBlanc, an aerospace engineer at NASA at the time, tested a prototype space suit in a huge vacuum chamber. The pressure relief hose detached from his clothing. Nothing major happened, nor did he suffer permanent damage, but this is how he remembered the last moment before losing consciousness:
“As I stumbled backwards, I could feel the saliva on my tongue starting to bubble just before I went unconscious, and that’s kind of the last thing I remember”
Among other things, the pressure suit protects against this. And from hypoxia, i.e. lack of oxygen (our body loses oxygen dissolved in the blood), which can be our loss much sooner than we boil. =)
Because without protective clothing, due to the pressure difference, our body can survive for barely 60 to 90 seconds.
Already at 4,500 meters, most people need supplemental oxygen. Passenger planes also have to comply with strict regulations for maintaining cabin pressure and providing additional oxygen. Skydrivers don’t usually reach this altitude and stay up there for a very short time in up there in the sky.
And the Sherpas?
They live at 3 – 4,000 meters in small villages in Nepal. Their bodies are also similary damaged by long-term or serial lack of oxygen (mainly neurologically), but this ethnic group is biologically structure differently. Research supports that they are genetically adapted to extreme conditions. Their bodies produce energy more efficiently and much more energy carriers (creatine – phosphate), which helps, for example, that their muscles are able to contract if they get less oxygen. Thanks to fewer red blood cells and higher levels of nitric oxide, their vessel walls only narrow at significantly lower pressures than any other people on Earth.
Incidentally, the name was given after Harry George Armstrong, the physician – general of the United States Air Force (February 17, 1899 – February 5, 1983). He was the first to recognize this phenomenon. He was a pioneer in the field of aviation medicine.
Be a Nerdy Bird!
