Editing Water vapor (section)

=== Sublimation ===
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[[Sublimation (phase transition)|Sublimation]] is the process by which water molecules directly leave the surface of ice without first becoming liquid water. Sublimation accounts for the slow mid-winter disappearance of ice and snow at temperatures too low to cause melting. [[Antarctica]] shows this effect to a unique degree because it is by far the continent with the lowest rate of precipitation on Earth.<ref>{{Cite web |title=The USAP Portal: Science and Support in Antarctica - About the Continent |url=https://www.usap.gov/aboutthecontinent/#:~:text=Antarctica%20is%20the%20coldest,%20windiest,sq%20km%20(5.4%20million%20sq. |access-date=2024-06-20 |website=www.usap.gov}}</ref> As a result, there are large areas where [[Millennium|millennial]] layers of snow have sublimed, leaving behind whatever non-volatile materials they had contained. This is extremely valuable to certain scientific disciplines, a dramatic example being the collection of [[meteorite]]s that are left exposed in unparalleled numbers and excellent states of preservation.

Sublimation is important in the preparation of certain classes of biological specimens for [[Scanning electron microscope|scanning electron microscopy]]. Typically the specimens are prepared by [[cryofixation]] and [[Electron microscope|freeze-fracture]], after which the broken surface is freeze-etched, being eroded by exposure to vacuum until it shows the required level of detail. This technique can display protein molecules, [[organelle]] structures and [[lipid bilayer]]s with very low degrees of distortion.