What is the coldest thing in the world? – By Lina Marieth Hoyos

https://ed.ted.com/lessons/what-is-the-coldest-thing-in-the-world-lina-marieth-hoyos

This lesson focuses on laser-imprisoned atoms that are relatively energyless. But the whole general area of cooling and supercooling is missing here, how refrigerators work in the first place, etc. and how 0 Kelvin was arrived at, among other things. Perhaps there is another TED-Ed lesson that puts this in perspective. Cool.