Solar Still

Aim: This activity is used to construct a solar still. 

Equipment: The equipment includes... 

• clear plastic sheeting;
• large stones;
• hole in the ground;
• bucket, billy can or similar container.

Method: Dig a hole in the ground and place a bucket, billy can or similar container down in the centre of the hole. Cover the hole with clear plastic sheeting and support the edges with a ring of rocks around the lip of the hole to hold the plastic tightly. Now place a single small stone in the centre of the plastic to create a conical effect for condensed water to dry down from. 

Background knowledge: The temperature within the hole rises due to the Sun's light and evaporate water from the soil. The vapour condenses on the plastic and runs down into the container. Solar stills use a simple evaporative method.