Making SOLID Nitrogen!

Liquid nitrogen, sure. We have that in dewar flasks from time to time.

Gaseous nitrogen, yeah, we have that at all times around us.

Solid nitrogen, though, that we don't get to see very often.

Then along comes Dr Derek Muller of Veritasium with a better dewar and a vacuum pump to produce a gorgeous, spinning disk of solid nitrogen floating like the thinnest, coldest hovercraft in the world.

I've actually seen crystalline nitrogen in my classroom before with a far less impressive set-up that Dr Muller used. I put a 50mL beaker (or maybe a 100mL, I don't remember) in a plastic bell jar attached to a decent but not world-class vacuum pump. As the pressure dropped, the temperature dropped as well, cooling the liquid nitrogen further and eventually hitting the freezing point of nitrogen at low pressure.

The liquid nitrogen froze into a puffy, crystalline network atop the liquid. Then the liquid boiled violently, pushing the crystals out of the way and turning them back to liquid. Liquid to solid to liquid to solid...boiling then calming down again and again.

It was quite a show.