The Moser Bottle Lamp: ‘Divine Light’

A close-up photograph of Alfredo Moser in the light of the bottle lamp - his makeshift invention.Sun Light in a Bottle

“God gave the Sun to everyone”, Alfredo Moser states modestly.  And Moser gave his light to everyone.  Over the last couple of years, Moser’s ingenious innovation has spread throughout the World, bringing the bottle lamps to locations from Brazil to the Philippines and Bangladesh.  By early next year, it is estimated that one million homes will have benefited from his simple idea… 

The inspiration came to Moser in 2002 during one of Brazil’s frequent electricity blackouts.

A plastic bottle filled with water and a drop of bleach, is inserted into a specially managed hole on the roof.



The refraction of sunlight powers it.  Depending on how strong the Sun is at any one time, the Moser lamp delivers about 40-60 watts.

For free.

Alfredo Moser went on to install the bottle lamps in neighbour’s houses and the local supermarket, in Uberaba (Southern Brazil), the city where he lives.


Divine Light Refraction

While many people in developed nations are affluent enough to enjoy revolutionising innovations and modern high-tech wonders in their homes, there are many places on Earth where shelter concerns are far more basic than those that people take for granted in the Western World.

For millions of those less fortunate people, the best new building product in the World might well be a discarded two-litre plastic soft drink bottle!

With little or no access to electricity, many around the World live in dark housing.

Piercing a hole in the roof admits only a concentrated beam of light that spreads little usable illumination throughout the interior.  However, a water-filled plastic bottle inserted through the roof gathers sunlight and diffuses it throughout the interior below.

A demonstration photograph showing the refraction of light in water. When plunging a plastic straw in a half-filled beaker, the straw appears crooked at the boundary between the air and the water.
The Refracted Image of a Plastic Straw in Water

A diagram explaining the refraction of light through water.

It works due to refraction.


Refraction is the bending of light, which is caused by a change in its speed, when it travels across different mediums (or substances).

The speed of light is determined by the density of the substance through which it passes.

So refraction occurs when light accelerates (or decelerates) from one substance to another with a different density – eg. when it passes from air to water.

Speed of Light in Different Materials

MediumSpeed of Light
vacuum186, 000 miles per second
air186, 000 miles per second
water140, 000 miles per second
glass124, 000 miles per second


In the case of the “Moser lamp”, the Sun‘s light is bent by the water in the bottle, and spreads around the room.


Zero Carbon Footprint to Change the World

While Alfredo Moser is credited with pioneering the use of plastic bottle skylights in Brazil, charities and non-government organisations like A Liter of Light are spreading the light throughout the World.  Following his method, My Shelter Foundation started making the lamps in June 2011.  They now train people to create and install the bottles, in order to earn a small income.

In the Philippines, where 1/4 of the population lives below the poverty line, and electricity is unusually expensive, the idea has really taken off, with Moser lamps now fitted in 140,000 homes.  Just one project under the My Shelter Foundation‘s good deeds, A Liter of Light uses the simple technology originally conceived by Moser in Brazil and optimised by MIT students to create social change in underprivileged  areas of the Philippines.  Along with funding from Pepsi, Bosch and other contributors,  the organisation hopes to transform the lives of 1/3 of Filipinos who are currently living in the dark.

According to online literature, three million households in the Philippines lack connectivity to the national grid and therefore lack decent lighting.  Additionally, many preventable  fires are caused by faulty connections, and made worse by the government’s inability to monitor informal settlements properly.  Both problems can be addressed with solar bottle bulbs, which are extremely easy to put together.

A photograph collage demonstrating how Alfredo Moser's bright idea is changing the World.
The Moser Solar Lamp: Changing the World with a Simple Idea

The ingenious idea has caught on in about 15 other countries, such as India and Bangladesh, Tanzania, Argentina and Fiji.

40-60 watts.  For free!!


Alfredo Moser remains humble.  His solar bottle lamp invention has not made him wealthy, but it has earned him a rightly deserved sense of pride.


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