Glaze ice is crystal clear. Somehow I remember I once read that boiled water can make clear ice but freezing rain are defiantly not boiling so I reckon it’s busted. Although the forming process of glace ice and clear ice cubes are different, it leads to a fun experiment.
How to make clear ice
First I need to understand why the ice cubes made from normal ice tray are cloudy. Water freezes from all four directions of the ice tray and push the air and impurities to the center of the cube, that’s the “cloud” you see.
Clear ice cube tray uses a method called “directional freezing”, it mimics how ice forms in the wild: water freezes from top to bottom thus push the air to the bottom. Ice machines, on the other hand, pumps water over evaporator and only water freezes.
I made a rough ice tray to test this theory:
Boiled water and a ginkgo leave