This curious lemon light exploits an old trick of creating electricity from a lemon (along with some zinc and copper metal). The device was created by artist Yuri Suzuki to highlight the wastefulness of society.
Suzuki has done a neat job of creating a lemon-half that contains the light and metals to utilise this eco friendly technology. I’d be interested to know how it was made, as it’s not obvious from the picture on how it was done!
Source: Make: Blog