In some of the most impoverished slums in our world, access to light within a dwelling is restricted by electricity and lack of windows to capture sunlight. As seen above, the only light available in these dwelling comes from the sun; and even then, this light is confined to a small patch, with darkness filling every other corner of the abode. 

We plan to give light to these dark corners, using DIY lights which require only a few ingredients:

  • Salt Water (fresh water is acceptable, but not as effective)
  • Bleach (not necessary but prevents algae growth)
  • Recycled Plastic bottles
  • Access to sunlight
  • Rubber sealant  
  • Recycled Lightbulb
  • Aligator clips
  • Recycled Aluminum or Zinc
  • Recycled Copper 

When touched by sunlight, the bottles will illuminate and their glow will radiate throughout a dark dwelling, making it easier for inhabitants to see within in their own home. Our lights are easy to produce and can be quickly made according to how much light is required. 

We intend to make two types of light: a Day Light that uses water to refract light from the outside into a dwelling and a Night Light which uses a series of salt water and copper and aliuminum cells linked in series in orrder to power a light bulb. 

Day Light

The Day Light is a form of skylight that transfers sunlight into a dwelling by refracting sunlight through water and displacing it. We tried a number of different solutions however, we found that saltwater (seawater) with bleach produced the brightest light in a dark environment (a box painted black). The salt particles allow more light to refract through the water and the bleach prevents algae growth whilst introducing a higher concentration of salt to the mixture. Seawater is also easily attainable for many and it doesn't require filtration or boiling.

The Day Light is an extremely simple design utilizing the following materials:

  • Recycled PET Water Bottle
  • Fresh or Salt Water
  • Bleach
  • Rubber Sealant


  1. We filled a bottle with seawater 
  2. We placed a tablet of bleach in the water to prevent algae growth
  3. For demonstration purposes we painted a recycled cardboard box and cut a hole in it to demonstrate a dark room
  4. We placed the bottle in the box and held it to direct sunlight to test the effect of the light dispersion
  5. We then refilled the bottle with just salt water and tested the effect
  6. The light wasn't as bright so the bleach was added again

The effect of the light is great and it allows for a room to be lit very effectively. By incorporating skylights rather than windows there will be fewer insects in the dwelling making it a much more pleasant environment to live or work in. 

 Night Light

The light we made for the day was a good start for us yet it begged the question, “What about when the sun goes down?” And so we decided to power a light bulb to act as the sun had, as aforementioned. The idea behind the Night Light was to light a single light bulb using a battery (a combination of cells) containing salt water, an aluminium anode and a copper anode. To turn on the bulb one would fill each plastic bottle with salt water and the water would act as a medium for the electrons to flow through.

The design utilized the following materials:

  • Recycled PET Bottles
  • Water
  • Salt
  • Anode (recycled aluminium foil)
  • Cathode (recycled copper pipe)
  • Electical Wire
  • Light Bulb and fitting


  1. Fill the bottles with salt water
  2. Cut slits in the bottles for the anodes and cathodes
  3. Attach aligator clips and wires to the anodes and cathodes
  4. Connect each cell in series to one another
  5. Test voltage and ampage with a multimeter 
  6. Connect to light globe and pray for success

Our battery consisted of 12 cells that combined outputted 13 volts in alternating current. This was great until we discovered that our current value was 0.01 Amps. To lower the voltage and increase the ampage we made a transformer out of a coil of aluminium wire. This increased the ampage to 0.03 Amps and decreased our voltage to 11.9 volts AC. This gave us a resistance value of 397 Ohms. This value is far too high to allow any real current to transfer through a circuit. We believe that the resistance is as a result of the water. By using Hydrochloric acid, we could hypothetically lower resistance and increase the current.

With our battery we were able to power a small LED bulb however, it wasnt large enough to be used as a household globe. With more time and more materials we would be able to create a battery with less resistance, but it is still an amazing feat to create 12 volts of electricity with ordinary materials that can be found anywhere.