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.
Fundamental Requirements. Army enlistment guidelines stipulate that you must be between the ages of 17 and 34, with at least a high school diploma. However, joining prior to age 18 requires consent from a parent or legal guardian. You must be in good physical health and pass a series of test to prove it.