Learn to Make a SOLAR STILL

A solar still distills water, using the heat of the Sun to evaporate, cool then collects the water. There are many types of solar still, including large scale concentrated solar stills, and condensation traps (better known as moisture traps amongst survivalists). In a solar still, impure water is contained outside the collector, where it is evaporated by sunlight shining through clear plastic or glass. The pure water vapour condenses on the cool inside surface and drips down, where it is collected and removed.

Distillation replicates the way rainfall occurs. The sun’s energy heats water to the point of evaporation. As the water evaporates, water vapour rises, condensing into water again as it cools and can then be collected. This process leaves behind impurities, such as salts and heavy metals, and eliminates microbiological organisms. The end result is pure distilled water.

You can easily make a solar still by following the steps below.

• The best thing about this renewable energy activity is that it would be useful to know how to do in nature if you had no fresh water to drink or in an emergency situation. A solar still is an easy way to distill water, using the heat of the sun to create evaporation from salt water or any impure water and turning it into fresh water, leaving the salt behind.
• Here, we will make a simpler version of a solar still with a glass bowl, a small glass jar, and plastic wrap.
• Fill a bowl with water and mix a few tablespoons of salt until it dissolves in the water. Put a glass jar in the centre of the bowl, and push it down. You do not want to get any of the salt water into the jar, so make sure the water is not too full in the bowl.
• Cover it all with a plastic wrap and seal it tight. Put a rock in the centre to weight it down and allow the water to fall into the jar. Place it outside in the warm sun for a few hours. What happens is that the water evaporates and collects on the plastic wrap. Then with the rock in the centre it causes the water to run down towards the jar and pool in the jar.
• If you let it work for several hours, there will be a small amount of water in the jar. Taste it, and the water will not taste salty, but fresh.

Source: http://teachbesideme.com/simple-science-making-solar-still/