The next time you go camping, instead of bringing batteries to keep your lantern running, you might only need to bring a salt shaker or a really sad book. Because Green House Co. Ltd., a Japanese company, has developed an LED light that runs on just salt water.
Using a dedicated water bag, campers would only have to mix up a saline solution of salt and H2O to keep the lamp glowing for up to eight hours at a time. The salty mixture serves as an electrolyte between a set of magnesium and carbon rods that function as negative and positive electrodes inside the lantern, producing electricity. It's not all virtually free energy, though. The magnesium rod is only good for about 120 hours of electricity production, but replacements will be sold separately when the lantern goes on sale sometime this month. [Green House via Tech-On!]