If you were making a list of things in life that are taken for granted, condensation could appear on it. Just to be clear:
Condensation is a process in which water in a gaseous state (water vapors) turns into a liquid state (water droplets) when the water vapors come into contact with a surface that is cooler. It is the physical change of gas to liquid that occurs when there is a significant drop in temperature, and it is the opposite of evaporation.
When you boil water on the stove in the winter, have you ever noticed that the windows get fogged up? The condensation on your windows is the result of water vapors hitting the cooler window and converting back to water droplets. Your kitchen becomes a mini-physics lab!
As mentioned earlier, water is critical to all living things. The way those living things get water represents a cycle of evaporation (clouds) and condensation (rain). Since most living things are composed mostly of water, they lose water through evaporation. Simply stated, by boiling some of those living things, like plants, you can catch the water vapors and turn the vapors into water droplets.
In fact, water evaporates from anything that has water in it—living or not. Water in mud puddles evaporates. Seawater evaporates. Water in sap evaporates. Urine evaporates. Water in clay will evaporate. Contaminated water will evaporate.
Catch enough water droplets and you have a water supply. Obviously, it takes a lot of water droplets to make a glass of water. The good news is that the evaporation process removes most impurities in the water.
Evaporation occurs when the object or item containing water is heated. To collect the water, you can set up a still. A still setup heats the substance to force evaporation. The evaporation is caught and channeled, and as it cools, it is converted to water droplets. Further channeling directs the water droplets into a container.
There are different types of stills that include:
- Vegetation still
- Sweat bag still
- Solar still (also called an evaporation still)
- Plastic bag or tarpaulin placed over a fire still
- Inflatable solar survival still (purchased)
The vegetation, sweat bag still, and solar still are discussed in detail in following sections.
The plastic bag or tarpaulin still is quite simple. A tripod is built out of sticks and placed over a fire. The tripod is capped with a plastic bag or tarpaulin that has had its edges folded to the inside to serve as a condensation catchment. A pot containing a substance with water content is placed over the fire. As the water evaporates, the tripod cap will catch the condensation.
Actually, anything able to be folded in a way that it can catch condensation can serve as a water collector over a heated substance in a container. For example, you can use a large flat leaf or saturated fabric or other items. The important thing to remember is to set up the water collecting system in a way that the cap over the fire and/or pot does not catch on fire.
Inflatable solar survival stills are usually carried on boats or life rafts. They are used to desalinate water to make the water drinkable. It distills collected sea water or contaminated water.