This happens because the temperature at which oxygen changes from a gas to a liquid is about 13 degrees Celsius above that of nitrogen. The oxygen can be seen dripping from the can just as on a humid day you can see drops of water condense and drip from a can you take from the refrigerator.
Though you technically can join the military up to age 42, if you're 35 or over you'll need an age waiver if you've never been in the military before.
Question: What is the maximum age to become an officer in the Military? Answer: By law, the maximum age for a commission is age 35. This is because a military officer must be able to have 20 years of service, to be retirement eligible by the maximum retirement age of 55. There are a few exceptions: Military medical officers and chaplains can be commissioned up to the age of 47 with waivers into their 50s (they also don't have to retire by age 55). Depending upon the need for doctors, psychologists, chaplains (all faiths), and legal officers as well, the maximum age can be waived.