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.
Army Requirements to Join When joining the Army there are specific age, citizenship, academic, physical and legal qualifications that you must meet first! To qualify for enlistment into the Army, you need these minimum requirements. Age Requirements You must be between the the ages of 17 and 35 (unless you have prior U.S. military service, or a specialized professional skill, such as a chaplain, lawyer or certain medical specialties).