A plastic bottle filled with water might not look like much, but when placed through a roof, it can act as a simple daytime light source. The idea, known as the “Moser lamp”, uses sunlight to brighten dark indoor spaces without relying on electricity.
The low-cost technique was developed in Brazil and later became popular in communities across several countries. Its appeal is pretty straightforward: it uses readily available materials and can bring natural light into rooms with few windows or little direct sunlight.
