This column is all about design that makes people’s lives better, so when I saw this film (on Russell Howard’s Good News of all places!) I knew I had to share it with you.
In Sitio Maligaya, a slum in the Philippines, homes are built so close together that they hardly see any natural daylight. Electricity is expensive and many homes are not connected to the mains. An incredibly simple and cheap solution based on an idea pioneered by Alfredo Moser in Brazil in 2002, epitomises what good design is all about and the power design has to change people’s lives.
Locals and volunteers take a discarded 1.5l plastic bottle and fill it with purified water. They add bleach to prevent algae from growing – this keeps the water clear for up to five years. They fix the bottle into a hole in the corrugated iron roof of each home. The light is refracted through the water and fills the space below with light – the same amount of light as a 55 Watt lightbulb – at virtually no cost at all.
This simple idea is now spreading. Philippines-based organisation My Shelter Foundation has launched an open-source movement called Isang Litrong Liwanag (A litre of light) through which over 200,000 bottle bulbs have been installed in communities around the world from Argentina to Zambia. They aim to install one million bulbs by 2015.

Further reading for the especially geeky:
