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.
But maybe you can use knowledge you have to help the military men by being a teacher there is always a way to be involved try that option with the army branch. source: Is it possible to join the army if you are 50 years old? what does a person have to do in order to get into the army?