These flashlights were called Faraday flashlights when they first came out, because they used principle of converting magnetism into electricity: shake a piece of metal between a pair of magnets and you get an electrical current. It is stored in a type of battery, and then all you have to do is add a bulb, and you have light.
When they first came out, the flashlights didn't work all that well. The bulb sucked the electricity out of the battery so fast that shaking it for a minute would only give you 30 seconds of usable light. However, the LED bulb changed this from a good idea on paper to a great idea in practice.
Requiring no batteries, and with a bulb life that is virtually infinite, the Gaiam Shakelight LED Flashlight is the best idea in flashlights since their invention. Shaking it for 10 seconds will give you about two minutes of light. Shake about 30 seconds, and you might get upwards of 15 minutes of light. Plus, the clear body lets you see the electricity being made. These are the best emergency and camping lights ever made, and they allow the Faraday principal to become practical in a handheld flashlight. Mine sits on my nightstand always at the ready!
How's that for shinning a light on living green?
Source: BecauseAction.com
