The south end of the Earth's axis is tilted toward the sun, summer in the Southern Hemisphere and winter in the Northern Hemisphere. "Equal night", twice a year, when the noon sun is directly overhead the equator, day and night are almost exactly 12 hours each everywhere on earth! September 22 is autumn equinox.
It depends on how this is done. If you raise the pressure, the nitrogen will disappear (liquify) and all that will be left will be the 21 % oxygen and the 1% argon.
The process is very complicated because the boiling point of nitrogen keeps on changing. The boiling point is unstable.
Plastics are non-corrosive and non-reactive in nature. So they are used for storing chemicals in the laboratory. They are used for strong chemicals because they do not react with chemicals neither do they corrode
