How to Make Oxygen a Liquid

Video Transcript

"Hi I'm Brian with EricksonTutoring.blogspot.com. Today we're going to discuss how to make liquid oxygen. So in order to make liquid oxygen, you need to take oxygen from its gaseous form and make it into a liquid. This occurs at negative 183 degrees Fahrenheit, so pretty cold. What we're going to do is we're going to take normal air and air contains mostly two compounds, nitrogen and oxygen. Nitrogen turns to a liquid at a negative 196 degrees so we're going to need to cool this down quite a bit. What we'll do is we'll go through several different cycles of cooling and compression so squeezing it and cooling it down, and then we'll go through an expansion phase as well. So you cool and compress it, that brings the temperature down. When you then let it expand, the temperature drops more. Run it through several cycles and you eventually get your sample cold enough to turn both substances into a liquid. Now what you do in order to just get pure liquid oxygen, you will let your mixture slowly heat up and when you reach negative 196 degrees, the nitrogen will turn into a gas and you'll be left with pure oxygen, pure liquid oxygen. That's the process for making liquid oxygen. Be careful though, it's flammable."