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The Wegener–Bergeron–Findeisen process (after Alfred Wegener, Tor Bergeron and Walter Findeisen []), (or "cold-rain process") is a process of ice crystal growth that occurs in mixed phase clouds (containing a mixture of supercooled water and ice) in regions where the ambient vapor pressure falls between the saturation vapor pressure over water and the lower saturation vapor pressure over ice.
To facilitate faster and more efficient freeze drying, larger ice crystals are preferable. The large ice crystals form a network within the product which promotes faster removal of water vapor during sublimation. [2] To produce larger crystals, the product should be frozen slowly or can be cycled up and down in temperature in a process called ...
Freezing things slowly allows the material time to re-arrange itself internally. In the example of water, ice forming slowly results in larger crystals leading to a clear glass like substance. If frozen quickly as with snow, the crystals are smaller and less organized, scattering light and appearing white.
Slow freezing leads to fewer but larger ice crystals while fast freezing leads to smaller but more numerous ice crystals. This difference in ice crystal size can affect the degree of residual enzymatic activity during frozen storage via the process of freeze concentration, which occurs when enzymes and solutes present in a fluid medium are ...
Freezing is a common method of food preservation that slows both food decay and the growth of micro-organisms. Besides the effect of lower temperatures on reaction rates, freezing makes water less available for bacteria growth. Freezing is a widely used method of food preservation. Freezing generally preserves flavours, smell and nutritional ...
In this case, food items are subjected to temperatures well below [clarification needed] the freezing point of water. Thus, smaller ice crystals are formed, causing less damage to cell membranes. [4] Flash freezing techniques are used to freeze biological samples quickly so that large ice crystals cannot form and damage the sample. [5]
On top of that, cold air can't hold much water vapor. Thus the water vapor doesn't stay in the air as it condenses out, giving you the cloud of ice crystals you see.
One example of deposition is the process by which, in sub-freezing air, water vapour changes directly to ice without first becoming a liquid. This is how frost and hoar frost form on the ground or other surfaces. Another example is when frost forms on a leaf. For deposition to occur, thermal energy must be removed from a gas.