Clean water is a basic human need that Swedish inventor Petra Wadstrom is helping to meet. She has invented a solar-powered water purifier that is simple to use. The 'Solvatten,' Swedish for “sun water,” purifies water by exposing it to UV rays. The design uses thermal-siphoning to ensure that all of the water will be exposed and made safe.

Once the unit is filled with water, it is placed in the sun and left until the face of the unit changes from red to green. The change in color indicates that the water is safe for consumption. Freshly treated water will also be warm and suitable for bathing or household chores.