When the power goes out on a dark evening, it's pretty annoying to have to scramble about to find candles, especially so if you don't have a flashlight. So how would it sound if you could run LED lights without and electrical power or batteries, and using household objects such as paper and salt water?
Interactive and electronic art teacher Emily Daniels has created these reusable water-controlled paper LED lights. After making two different designs (flower and lamp) with the soda box cardboard, Emily made six pairs of dots in the petals and base of the lamp. In the holes, she threaded thin copper and aluminium (you could use zinc instead) wires. Once a base is added and each of the wires hand-twisted to their neighbor, the copper and aluminium/zinc wire left can be attached the an LED light. Finally, wet your finger in salted water (or lemon juice), touch each segment of the paper and enjoy the light the LED will let off!
The light switches on once you have dabbed your finger because skin acts as a conductor, so touching the wires will create a a power surge to turn on the LED. The paper will absorb the salt water, allowing the light to remain switched on for around two additional hours. Emily also adds that she was able to use the lights six more times before the metal oxidizes and will need to be replaced.
The children she demonstrated the experiment to certainly looked like they had fun trying it out, but the lights could be really useful in serious situations -- like a power cut or a longer term problem meaning no electricity -- and it's recycling unwanted products.
You can learn to make one of your own very quickly on Emily's Instructables post.
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