How is liquid helium made?

Question

As it is at only 4 degrees Kelvin above absolute zero

Answer 1

Increase the pressure enough and it will turn to its liquid form.

As a general rule with gases, you'll get a state change whenever you tinker with temperature and/or pressure.

Answer 2

you use liquid nitrogen to bring the temp down to 193 then?

Answer 3

historically i think by pressurising one cooled gas to liquid... allow that to evaporate a bit so it cools further.  use that to cool another pressurised gas, which turns to liquid.

allow that to evaporate, to cool another pressurised gas....

after a long chain of different gases and with lots of pressure you can get to liquifying helium.

Also i think it took several teams several decades to actually achieve.  Now, i dont know what they do.. something similar but with fewer gases in the chain i imagine.

this

http://www.knaw.nl/waals/pdf/kamerllingh...

is a pdf of Onnes' original paper, including description of the process, pictures and diagrams of the apparatus. they often used glass vessels.  combine that with the pressures involved, you'll undertand why a lot of technicians lots their eyesight in the quest for liquid helium!

enjoy