I made about 50 ml of liquid oxygen by passing medical grade oxygen through a condenser in a dewar of LN2. The photo shows it adhering to a magnet, due to it’s paramagnetism.
“Continue reading” for more interesting liquid oxygen stuff including paramagnetism.
I made it out of copper tubing which then dripped and sputtered into the container with a gas flow rate of about 1-3 l/min. The LOX container is kept in the bath of LN2 to stop it bubbling away. Nitrogen turns liquid at -196 C and hence can turn oxygen liquid as it has a higher temperature of -183 C.
This is the double walled LN2 dewar for transport from the gas company. It has a soft sponge plug which is loose and the cap sits on top.
The medical oxygen cylinder with the gauge on the left reading 3 litres per minute.
My own dewar out of its protective box. Next to it is the copper coil condenser which fits inside it. Oxygen gas intake is at the top and the lower end drains the liquid oxygen into the test tube. This test tube sits in the pool of LN2 to keep it cold.
A view down into the dewar. The copper coil is around a larger collecting container and the oxygen outlet is the blurred tube at top right which is splashing LOX into the container.
The blue tinge of LOX against white paper. By contrast, LN2 is colourless. There is a magnet suspended in it keeping cold. The container was just out in the air for a moment but frosting starts within seconds.
I have been able to confirm that LOX will adhere to a magnet due to its paramagnetic properties. The close up photo (the first one on this page above) of a small NIB magnet with a crown of LOX over the top giving the muffin like appearance to the NIB. There is a blanket of cold oxygen above it from the boiling LOX which in still air was very clearly defined. The set-up was on an upside down Styrofoam cup as a very shallow insulating dish.
This photo shows how LOX remains on the ends of a magnet where the field is strongest. This does not happen with liquid nitrogen.
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Photo Date: 2007