Tom Rankin
Well-known member
"Batteries are bulky, expensive, and risk polluting the environment with harmful chemicals when improperly disposed of. This DIY water-powered flashlight, however, uses an energy source that’s safe and free."
http://www.mentalfloss.com/article/73805/how-make-flashlight-runs-water
http://www.mentalfloss.com/article/73805/how-make-flashlight-runs-water