> How is the boiling point of any of these elements determined? I cant imagine that we got some helium in its gaseous form and cooled it down below -267 degrees

> How is the boiling point of any of these elements determined? I cant imagine that we got some helium in its gaseous form and cooled it down below -267 degrees and then heated it up slowly to find out. Why not? That's relatively easy to do in any moderately equipped physics lab.