The US Department of Agriculture apparently has a “Low Temperature Scanning Electron Microscope” at the Beltsville Agricultural Research Center in Maryland that allows them to get some amazing photos of snowflakes, according to a post on Twisted Sifter.
Samples of snow, ice and associated life forms are collected by dislodging the crystals or biota from the face of a snow pit or the surface of the snow onto copper metal sample plates containing precooled methyl cellulose solution. Within fractions of a second these plates are plunged into a reservoir of liquid nitrogen which rapidly cools them to -196°C and attaches these pre-frozen materials to the plates. . . After arrival at the Beltsville Electron Microscopy facility, the copper plates can be stored at -196°C in storage dewars. Selected samples are transferred to the preparation chamber for sputter coating with platinum. This renders them electrically conductive and they are placed on the pre-cooled (-170°C) stage of a Hitachi S-4100 field emission Scanning Electron Microscope where they are imaged and photographed.
So that’s how they do it. Click the link to see a few more of the images and then realizes that on a powder day we go blowing through billions of these crazy micro architectural masterpieces.
[Link: Twisted Sifter via Boing Boing]
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