Using liquid nitrogen and an aluminum can, you can make a decent amount of liquid oxygen in just a matter of minutes! With this technique, enough liquid oxygen can be made for cold combustion classroom demonstrations EASILY within ten minutes or less, from start to finish.
Since the boiling point of nitrogen(-196°C) is lower than that of oxygen (-183°C), and because aluminum is quite efficient at thermal conduction, when an aluminum can contains liquid nitrogen, oxygen from the air will readily condense along the sides. With a very cold place to collect it, liquid oxygen can be dripped into a container and then used for some excellent demonstrations showcasing paramagnetism, concentration effects on kinetics, and some VERY cold combustion!
