Solar still

A solar still distils water with substances dissolved in it by using the heat of the Sun to evaporate water so that it may be cooled and collected, thereby purifying it. They are used in areas where drinking water is unavailable, so that clean water is obtained from dirty water or from plants by exposing them to sunlight.

Dig a hole about a metre square, and at the bottom place the cup that will catch the condensed water. Pack as much green vegetation around the mug in the hole. Plastic (or small branches) is placed over the pit with a small stone in the centre, forming a funnel to direct the condensed water into the cup. The completed trap is left overnight, and moisture can be collected from the cup in the morning. Where possible, boil the water for at least 5 minutes before drinking.