For a incorporate of years, I was working with superfluid helium in a low-temperature physics lab. Helium is the second lightest element, right after hydrogen, the lightest. Like all gases, helium changes from the gaseous state to the liquid state when cooled down sufficiently. (Some gases additionally need higher than atmospheric pressure to get liquid.) But at normal pressure, it will never solidify. And amongst its other spectacular, properties, when cooled down nearly to the absolute Zero of temperature, liquid helium acquires the potential to move without friction, a asset which is called "Superfluidity".
In that strange state, it is the ideal cooling medium if you have to cool something down to temperatures that low. "Superfluid helium" is somewhat long if you have to say and write it hundred times a day. So physicists call it helium two, written HeIi.
We have been a bunch of excited citizen working long hours in the lab doing superfluidity research. Everyone we had contact with was somehow related to our work. Everyone understood what we meant when talking about HeIi.
Our work was not just basic research. We worked for an application of our findings. In those days, there have been outer space telescope projects like the Iras satellite where sensors had to be liquid helium cooled to work properly. Our team was to supply a means to operate a superfluid helium tank which had to be taken into orbit alongside with the other appliances.
In orbit, there is no gravity. You may have seen Tv pictures of citizen and stuff aboard a space shuttle thoughprovoking nearby in all directions, and water drops exactly round floating in mid-air. Well, think of your soda drink. Usually it will pretty much stay put in which ever package you may keep it. It will not creep out by itself, because of its own weight, or differently stated: Because gravity keeps your drink where it belongs. But in an orbit with zero gravity, how to keep our liquid HeIi nice and well-behaved? - If questions like this one have to be dealt with, of course you will not say "at zero gravity" all day long. The usual stamp for "gravity" is "g". So physicists would say: "at g equal zero" or "at zero g" and write "g=0".
The colleague with whom I worked closest in those days was a nice young blond lady. I told you already that we have been excited about our work, so don't suppose whatever now. When funds were low again and her contract was about to finish, rather than looking for someone else great paid job, she was seeking unemployment benefits to be able to continue work "free of charge" for our project and bridge the gap to our next project funding date. So she had to go out to the real world face the lab.
She came back somewhat bewildered from her visit to the employment office. "The lady there asked me what I am presently doing and how I am paid. So I told her I am working with HeIi at zero g. She then got a very strange disquieted expression on her face, no idea why. I figured I'd great go!" - Well, it took me a while, but finally it dawned on me... We had just lost touch with the world face our niche. Must have been some alien contact for that employment office employee. My colleague was lucky to have such an secure look; else she might have ended up in a strait jacket.
Guess why scientists are always depicted as maniacs in cartoons.
If you are curious in a look at the ultimate world of physics which doesn't want you to be first introduced to highly outlandish lingo, and specifically if you are curious in helium, have a look here:
Regards,
For Us It's Life - But For Most It's Science Fiction