Litre of Light

Today’s post is actually a little science project to make over the long school holidays with kids.  It’s particularly relevant if you live somewhere like Johannesburg where sunshine is plentiful, but the power supply is not.

Sweetpea announced that she wants to be an inventor.  I’m not the best person to help.  I pretty much completely missed out science during my own expat education.  Moving between British, Dutch and American school systems it was accidentally circumnavigated.  Who knows, maybe I could have been a rocket scientist.

Or quite probably not. The Litre of Light is the brainchild of Brazilian, Alfredo Moser. In a nutshell a litre of light is a solar “lightbulb” made with a few basic materials; a large clean empty plastic bottle, a couple of capfuls of bleach, filtered water, sealant to keep the bottle airtight and a square of corrugated iron. Once installed on a roof top, sunlight reflects through the bottle to provide light equivalent to approximately 50 watts during the day.

Moses’s lightbulb moment has provided rays of light to plenty of people living in windowless slums and townships across the globe.  It something could be really useful here in South Africa, so I figured it would be a fun AND practical project to test with the kids. I also figured it was so simple that even a science dummy could make one. We scaled back on the materials to make a child friendly version. I decided we could forgo the bleach, its purpose is to stop the water clouding when the ‘bulb’ is a permanent fixture. As we weren’t installing it on a rooftop, it seemed both unnecessary and a safer option with the kids. We used:

IMG_5987 1

  • An empty cereal box (any box will do, shoe box, packing box)
  • Bottled water 75l bought at the supermarket (and still sealed).
  • Sticky Tape
  • Scissors and a Pen

First we turned the box upside down and drew around the bottom of the bottle on the sealed end of the box. IMG_5988 1 IMG_5989 1Using the scissors, we skewered a hole in the middle of the circle and cut strips from the centre to edge of the circle. 

IMG_5990 1 We pushed the bottle from the inside of the box and secured it (badly) with sticky tape.  On the side of the box we skewered a peep hole.

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Let there be light: We took the box outside in the sun and peeped. If you look carefully you can see the wording on the inside of the box.               IMG_6017 1

The kids were massively impressed (and so was I). We made a second version with a clear plastic bottle (the first one was blue), a much thicker cardboard box and put tin foil on the top to mimic the corrugated iron used on the real deal version (not sure if it’s supposed to reflect more light or just sit well on a corrugated rooftop on a shack). Either way, the light seemed to shine more brightly. IMG_4216 1 IMG_4217 2

To see how to make the bells and whistles real deal version for your shed, shack or extra credit school project, click here for detailed instructions.  Litre of Light won’t fix your load shedding blackout woes, but it is certainly an inexpensive and genius idea that could be of real use in South Africa during daylight hours. Maybe I’m not so terrible at this science lark.  Tomorrow we move on to rocket science.  Just kidding.

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