The guys over at Popular Science show us how to heat a hot tub using quicklime, rather than electricity — might come in handy when the power goes out. Video after the break.

Rather like a reverse-Bain Marie, the guys floated three metal tubs, each containing fifty pounds of quicklime, in the “jacuzzi.” When water was added to each container, the quicklime fizzed away, heating the 700 or so gallons of water to the perfect temperature, 100F

[via GizmodoPopSci]